Open access

Original research

Yuji Nishizaki ‍ ‍,1 Kazuya Nagasaki,2 Kiyoshi Shikino ‍ ‍,3 Masaru Kurihara ‍ ‍,4
Tomohiro Shinozaki ‍ ‍,5 Koshi Kataoka,1 Taro Shimizu,6 Yu Yamamoto,7
Sho Fukui ‍ ‍,8 Sho Nishiguchi ‍ ‍,9 Kohta Katayama,10 Hiroyuki Kobayashi,2
Yasuharu Tokuda ‍ ‍11,12

To cite: Nishizaki Y, Nagasaki K,
Shikino K, et al. Relationshipbetween COVID-­19 care andburnout among postgraduate
clinical residents in Japan:
a nationwide cross-­
sectional study. BMJ Open
2023;13:e066348. doi:10.1136/
bmjopen-2022-066348► Prepublication history andadditional supplemental material
for this paper are available
online. To view these files,
please visit the journal online(http://dx.doi.org/10.1136/​
bmjopen-2022-066348).

Received 05 July 2022
Accepted 30 December 2022

© Author(s) (or theiremployer(s)) 2023. Re-­use
permitted under CC BY-­NC. No
commercial re-­use. See rights
and permissions. Published by
BMJ.
For numbered affiliations see
end of article.
Correspondence to
Dr Yuji Nishizaki;y​ nishiza@​juntendo.​ac.​jp

ABSTRACT
Objective The relationship between the care of patientswith COVID-­19 and mental health among resident
physicians in Japan is imperative for ensuring appropriate
care of patients with COVID-­19 and should be clarified.
We herein assessed the relationship between the careof patients with COVID-­19 and mental health among
postgraduate year 1 (PGY-­1) and PGY-­2 resident physicians
and factors associated with mental health.
Design This nationwide cross-­sectional study analysed
data obtained using the clinical training environment self-­reported questionnaire.
Setting An observational study across Japan amongresident physicians (PGY-­1 and PGY-­2) from 583 teaching
hospitals.
Participants Examinees who took the general medicine
in-­training examination of academic year 2020.
Primary and secondary outcome measures The
Patient Health Questionnaire and Mini-­Z 2.0 were used
to assess mental health, and experience of caring forpatients with COVID-­19 was divided into three groups(none, 1–10 and ≥11). The prevalence of mental conditionsin the three groups was compared using the ‘modified’Poisson generalised estimating equations by adjustingfor prefecture-­level, hospital-­level and resident-­levelvariables.
Results Of the 5976 participants analysed, 50.9% were
PGY-­1. The prevalence of burnout was 21.4%. Moreover,
47.0% of all resident physicians had no experience in thecare of patients with COVID-­19. The well-­experienced
group accounted for only 7.9% of the total participants.
A positive association was found between the number ofcaring patients with COVID-­19 and burnout (prevalence
ratio 1.25; 95% CI 1.02 to 1.53). Moreover, the shortage of
personal protective equipment was identified as a major
contributor to burnout (prevalence ratio 1.60; 95% CI 1.36
to 1.88).
Conclusions Resident physicians who experienced
more care of patients with COVID-­19 had slightly greaterburnout prevalence than those who did not. Approximately
half of resident physicians did not participate in the care ofpatients with COVID-­19, which posed a challenge from an
educational perspective.

STRENGTHS AND LIMITATIONS OF THIS STUDY⇒ This study investigated the relationship between thecare of patients with COVID-­19 and mental healthstate among postgraduate clinical resident physicians during the COVID-­19 pandemic in Japan using
nationwide data.
⇒ The resident physicians voluntary participated inthis study; however, there was a bias towards theinclusion of highly motivated resident physicians.
⇒ We did not collect information regarding the residents’ baseline psychiatric illnesses and personalities, which could have an impact on our study
results.
⇒ The number of patients with COVID-­19 who experienced care was based on self-­reports by resident
physicians, which could be inaccurate.

INTRODUCTION
The outbreak of a COVID-­19 across China
in December 2019 had eventually led to its
explosive spread worldwide, prompting the
WHO to declare COVID-­19 a pandemic by
March 2020.1 This pandemic has substantially increased the demand for medicalcare, causing detrimental effects, including
burnout and depression, on the mental
health of healthcare workers, with effects
that continue to this day.2 3 Several reports
have indicated that young physicians, suchas resident physicians, are more susceptible
to mental health problems than older physicians and are considered a high-­risk group.4–6
Hence, residency training organisations aretaking steps to protect the mental health ofresident physicians from the negative effectsof the pandemic.
The COVID-­
19 pandemic causes psychological stress in resident physicians due toincreased workload, trauma, unsafe environment, limited training and limited private

Nishizaki Y, et al. BMJ Open 2023;13:e066348. doi:10.1136/bmjopen-2022-066348

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Relationship between COVID-­19 careand burnout among postgraduate
clinical residents in Japan: a nationwide
cross-­sectional study

Open accessand ethics in addition to basic clinical knowledge andskills for resident physicians. A computerised national
matching system has been introduced to allow medical
students to apply to any clinical training hospitals acrossJapan. In 2021, 1021 clinical training hospitals have been
established. After the 2-­year postgraduate super-­rotation
residency programme, most resident physicians enter
specialty-­based senior residency training in Japan.
Participants in this study were resident physicians(PGY-­1 and PGY-­2) who underwent the general medicine
in-­training examination (GM-­ITE) at the end of the 2020
academic year (from 18 to 31 January 2021) in Japan.
Immediately after the GM-­ITE, participants were asked
about their clinical training environment through a self-­reported questionnaire, including resident physicians’
mental health condition and the number of experiencing
care for patients with COVID-­19. All participants readthe research document explaining data anonymisation,
voluntary and the publication of study results prior toparticipation. Only participants who provided consent toparticipate were included herein. Participants were also
provided the opportunity to opt-­out.
Patient and public involvement
This study was not appropriate to involve patients or the
public in the design because all participants of this study
were resident physicians.

METHODS
Study design and population
This nationwide cross-­sectional study involved postgraduate year 1 (PGY-­
1) and PGY-­
2 resident physicians inJapan. We used the clinical training environment froma self-­reported questionnaire to evaluate the relationship between resident physicians’ mental health condition and the number of experiencing care for patientswith COVID-­19. This study followed Strengthening theReporting of Observational Studies in Epidemiology
guidelines.
Under the Japanese medical education system, after
graduating from a 6-­year medical course and passing the
National Examination for Doctors, postgraduates participate in a super-­rotation residency programme for 2 years.
Resident physicians in Japan are mandated to rotate
among seven clinical departments (internal medicine,surgery, emergency medicine, paediatrics, obstetrics andgynaecology, psychiatry, and community-­based medicine)and experience general outpatient management at least
for 2 years. The Ministry of Health, Laborand Welfare is
responsible for establishing clinical training guidelines,
regulating clinical training programmes, and setting
goals for acquiring communication skill, professionalism

Measurements
We collected data on resident physicians’ characteristics(PGY and sex), working environment (number of monthly
emergency department (ED) duty, weekly duty hour,number of experiencing care for patients with COVID-­19
during their clinical training and personal protective
equipment (PPE) supply status) and mental health conditions (burnout, depression, high stress condition andhigh job satisfaction) through a self-­reported questionnaire. Hospital information (type of hospital, categoryof infectious disease designated medical institution andlocation) and prefecture information (population andhigh incidence area of COVID-­19) were also determinedfrom the published web page. The endemic areas were 23of the 47 prefectures, including Saitama, Chiba, Tokyo,
Kanagawa, Osaka, Hyogo, Fukuoka and Okinawa.
Mental health conditions (burnout, depression, highstress condition and high job satisfaction) were set as
the dependent variable during multivariate analyses. To
decrease the burden of the questionnaire immediately
after the GM-­ITE, we selected a brief scale for assessingthese mental health conditions. The Patient Health
Questionnaire 2 (PHQ-­2) was used to assess depression,
whereas the Mini-­Z 2.0 was used to assess burnout, highstress condition and high job satisfaction.14 The PHQ-­2 isa screening test for depression and contains two questions
that ask respondents whether they had experienced a lossof interest or pleasure and a depressed mood during thepast 2 weeks. Responses were collected in a dichotomous‘yes’ or ‘no’ format, with a ‘yes’ answer to either question2

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activities.7–9 In many countries, resident physicians andmedical students are involved in the care of patients with
COVID-­19.10 Burnout, depression and stress conditions
among resident physicians negatively affect not only theresident physicians themselves but also their institutions
by increasing work absences and patient safety risk.6
However, not all physicians are directly involved withthe care of patients with COVID-­19, with some reportssuggesting reduced working hours due to fewer patientswith other concerns.11 Moreover, a significant number oftraining hospitals may prevent resident physicians frombeing involved with the care of patients with COVID-­19 tohinder the spread of infection among healthcare workers.
Identifying the extent of resident physicians’ depression
and burnout during the current pandemic and examining associated factors will help protect their mental
health and promote the development of a sustainable
healthcare system. However, despite the growing body ofresearch on the mental health of resident physicians, very
little has been conducted in Japan.12 13 Moreover, available studies have not primarily focused on resident physicians and have been relatively small in size, suggesting theneed for high-­quality research targeting a larger numberof resident physicians.
Therefore, we conducted a survey on the mental health(depression, burnout, stress and job satisfaction) andexperiences with the care of patients with COVID-­
19
among resident physicians in Japan during the COVID-­19
pandemic and evaluated the association between resident
mental health and COVID-­
19 practice. We also assess
factors associated with mental health among resident
physicians in Japan.

Open accessterms of prevalence ratios (PRs) estimated using clusteredlog-­linear ‘modified’ Poisson models in which hospitalvariation was accounted for as clusters in generalised
estimating equations, assuming the compound symmetry
structure as working correlation matrix. None of experience with the care of patients with COVID-­19 was used as
the reference for analysis. The models were adjusted forthe type of hospital, category of infectious disease designated medical institution, population, high incidence
area of COVID-­19, sex, grade, ED duty, PPE supply status,
duty hour. All analyses were conducted using SAS V.9.4.

Statistical analyses
The association between the care of patients with
COVID-­19 and mental health conditions was examined in

RESULTSA total of 7669 residents from 593 teaching hospitals
joined in the 2020 GM-­ITE. Among them, 6816 responded
to the self-­reported questionnaire survey, resulting ina response rate of 88.9%. We excluded resident physicians with any missing data, ultimately including datafor 5976 resident physicians from 583 teaching hospitals
for analyses. Table 1 summarises the participants’ background information. Accordingly, 47.0% of all resident
physicians had no experience in the care of patientswith COVID-­19. Even among the resident physicians inhigh incidence area of COVID-­19, 38.1% of the resident
physicians had no experience with the care of patientswith COVID-­
19. The well-­experienced group, definedas those who encountering≥11 patients with COVID-­19,
accounted for only 7.9% of the total participants. Among
the resident physicians, 32.0% were female, 49.1% were
PGY-­2, 83.6% were from community-­based hospitals and
33.0% were located in urban areas. A positive association
was noted between the number of experiencing care forpatients with COVID-­19 and urban area, population, highincidence area of COVID-­19, male sex, PGY-­2, number ofmonthly ED duty, weekly duty hour and GM-­ITE Score.
Among resident physicians, 21.4% (1277/5976) experienced burnout, 29.4% (1758/5976) experienced
depression, 39.2% (2342/5976) experienced high stresscondition and 62.4% (3731/5976) experienced high job
satisfaction. Tables 2–5 detail the relationship between thenumber of experiencing care for patients with COVID-­19
and mental health conditions (burnout, depression, highstress condition and high job satisfaction) using multivariate analysis. As shown in table 2, only a positive association
was observed between the number of experiencing carefor patients with COVID-­19 and burnout (PR 1.25; 95%
CI 1.02 to 1.53). A major factor associated with burnout
was the shortage of PPE (PR 1.60; 95% CI 1.36 to 1.88) asshown in table 2. Factors associated with burnout, except
for the number of patients receiving COVID-­19 care andthe shortage of PPE, were follows: quartile 2 of population(PR 1.27; 95% CI 1.01 to 1.59), female sex (PR 0.85; 95%
CI 0.77 to 0.94), PGY-­2 (PR 0.87; 95% CI 0.79 to 0.95) andmoderate ED exposure (3–5 per month) (PR 0.70; 95% CI
0.51 to 0.96) (table 2). As shown in table 3, we indicatedno relationship between the number of experiencing carefor patients with COVID-­19 and depression. As shown inNishizaki Y, et al. BMJ Open 2023;13:e066348. doi:10.1136/bmjopen-2022-066348

3

General medicine in-training examination
In the USA, an in-­training examination to assess clinical knowledge called the Residency Internal Medicine
In-­Training Examination (IM-­ITE) is administered during
training.21–23 The GM-­ITE is an examination administeredin Japan using a methodology similar to that for IM-­ITE.
The purpose of the GM-­ITE is to provide resident physicians and training programme directors with an objective,
reliable and valid assessment of clinical knowledge. The
current GM-­ITE consists of 60 questions across four main
subjects: medical interview and professionalism, symptomatology and clinical reasoning, physical examinationand clinical procedures, and disease knowledge, withsome questions presented in video and audio format. The
GM-­ITE was developed by the JAMEP (Japan Institute forAdvancement of Medical Education Program), a non-­profit organisation, in 2011 and has been administeredcontinuously every year since then. The questions aredeveloped annually by a committee of experienced physicians and peer reviewed by an independent committee.
The GM-­ITE can only be taken by resident physicians who
belong to training hospitals authorised to administer theGM-­ITE.24–26

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indicating a positive depression screening. A Japaneseversion of the PHQ-­2 is available, the validity of which has
been previously evaluated.15 A meta-­analysis reported thatthe questionnaire has a sensitivity of 76% and a specificityof 87% for diagnosing major depression.16 The Mini-­Z
2.0, which also has a Japanese version, is a 10-­item questionnaire that assesses physicians’ well-­being.17 The single
questions for burnout, stress and satisfaction included in
the Mini-­Z 2.0 were used in this study. A previous study
had shown that a ‘single-­item measure of burnout’ wasassociated with higher levels of emotional exhaustion(EE).18 The diagnostic properties of the single-­
item
measure of burnout have been investigated in both theoriginal and Japanese versions.19 20 The Japanese version
has a sensitivity of 54% and a specificity of 88% for the
diagnosis of burnout, which were comparable to thoseof the original version.20 Each question was rated on a5-­point Likert scale, the scoring for which is described in
the online supplemental appendix 1.
In this study, the main independent variable of interest
was the number of experiencing care for patientswith COVID-­19 during clinical training in the current
pandemic. The number of experiencing care for patientswith COVID-­19 was self-­reported based on the following
five categories: category 1 (0 patient), category 2 (1–10
patients), category 3 (11–20 patients), category 4 (21–30
patients) and category 5 (31 patients or more). During
the analysis of the afore-­mentioned data, the numberof categories was reclassified from 5 to 3 given that the
number of responses for categories 4 and 5 was extremely
small for any question.

Open access

Experience with care of patients with COVID-­19
Total(n=5976)None(n=2807)

Moderated experienced
1–10 (n=2698)

Well experienced≥11 (n=471) Quartile 1 (573 441–1 786 170)

1513 (25.3)

1049 (37.4)

394 (14.6)

70 (14.9) Quartile 2 (1 815 865–3 700 305)

1401 (23.4)

840 (29.9)

517 (19.2)

44 (9.3)

P value

Prefecture information
Population, n (%)<0.001 Quartile 3 (5 101 556–7 483 128)

1507 (25.2)

544 (19.4)

831 (30.8)

132 (28.0) Quartile 4 (8 839 469–13 515 271)

1555 (26.0)

374 (13.3)

956 (35.4)

225 (47.8)

High incidence area of COVID-­19*, n (%)<0.001 No1332 (22.3)

1037 (36.9)

265 (9.8)

30 (6.4) Yes4644 (77.7)

1770 (63.1)

2433 (90.2)

441 (93.6) Community-­based hospital

4996 (83.6)2323 (82.8)2284 (84.7)

389 (82.6) University branch hospital

306 (5.1)

88 (3.1)

178 (6.6)

40 (8.5) University hospital

674 (11.3)

396 (14.1)

236 (8.7)

42 (8.9)

Hospital information
Type of hospital, n (%)<0.001Category of infectious disease designated medical institution, n (%)<0.001 Designated medical institution for infectious disease2487 (41.6)

1339 (47.7)

958 (35.5)

190 (40.3) Non-­designated medical institution for infectious disease3489 (58.4)

1468 (52.3)

1740 (64.5)

281 (59.7) Urban area

1971 (33.0)

590 (21.0)1129 (41.8)

252 (53.5) Rural area

4005 (67.0)2217 (79.0)

1569 (58.2)

219 (46.5)

Location, n (%)<0.001

Resident information
Sex, n (%)<0.001 Male4064 (68.0)

1797 (64.0)

1915 (71.0)

352 (74.7) Female1912 (32.0)1010 (36.0)

783 (29.0)

119 (25.3)

Grade, n (%)<0.001 PGY-­13041 (50.9)1483 (52.8)

1375 (51.0)

183 (38.9) PGY-­22935 (49.1)

1324 (47.2)

1323 (49.0)

288 (61.1)

Emergency department duty, n (%)<0.001 0 per month

220 (3.7)

149 (5.3)

65 (2.4)

6 (1.3) 1–2 per month909 (15.2)

502 (17.9)

360 (13.3)

47 (10.0) 3–5 per month4205 (70.4)

1991 (70.9)

1895 (70.2)

319 (67.7) >6 per month

611 (10.2)

147 (5.2)

367 (13.6)

97 (20.6) Unknown

31 (0.5)

18 (0.6)

11 (0.4)

2 (0.4)PPE supply status, n (%)

0.02 Sufficient supply

5017 (84.0)2315 (82.5)2310 (85.6)

392 (83.2) Intermediate supply

611 (10.2)

319 (11.4)

245 (9.1)

47 (10.0) Insufficient supply

348 (5.8)

173 (6.2)

143 (5.3)

32 (6.8) 0–59 hours per week

2517 (42.1)

1351 (48.1)

1027 (38.1)

139 (29.5) 60–79 hours per week

2264 (37.9)

1002 (35.7)

1069 (39.6)

193 (41.0) >80 hours per week

1195 (20.0)454 (16.2)

602 (22.3)

139 (29.5)

Duty hour, n (%)<0.001*High incidence area of COVID-­19 was defined as prefectures designated as endemic or non-­endemic areas by setting the median of the cumulative number ofpatients with COVID-­19 between 1 April 2020 and 31 January 2021 as the cut-­off value.
PGY, postgraduate year; PPE, personal protective equipment.

table 4, we also indicated no relationship between thenumber of experiencing care for patients with COVID-­19
and high stress condition. In addition, we did not findstatistically significant association between the number ofexperiencing care for patients with COVID-­19 and highjob satisfaction (table 5).

4Nishizaki Y, et al. BMJ Open 2023;13:e066348. doi:10.1136/bmjopen-2022-066348

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Table 1 Background information categorised according to experience with care of patients with COVID-­19

Open access

95% CIn

Burnout (%) aPR*

Lower limit Upper limit P value

Prefecture information
Population Quartile 1 (573 441–1 786 170)

1513 303 (20.0)

1 (reference) Quartile 2 (1 815 865–3 700 305)

1401 324 (23.1)

1.27

1.01

1.59

0.03

 Quartile 3 (5 101 556–7 483 128)

1507 308 (20.4)

1.06

0.82

1.37

0.66

 Quartile 4 (8 839 469–13 515 271)

1555 342 (22.0)

1.16

0.90

1.50

0.24

 No

1332 280 (21.0)

1 (reference) Yes4644 997 (21.5)

0.92

0.73

1.16

0.47

 Community-­based hospital

4996 1048 (21.0)

1 (reference) University branch hospital306

70 (22.9)

1.04

0.77

1.41

0.78

 University hospital674

159 (23.6)

1.04

0.86

1.26

0.67

0.83

1.07

0.38

0.77

0.94

0.001

0.79

0.95

0.002

High incidence area of COVID-­19†

Hospital information
Type of hospitalCategory of infectious disease designated medical institution Designated medical institution for infectious disease2487 545 (21.9)

1 (reference) Non-­designated medical institution for infectious disease3489 732 (21.0)

0.95 Male4064 908 (22.3)

1 (reference) Female1912 369 (19.3)

0.85 PGY-­13041 691 (22.7)

1 (reference) PGY-­22935 586 (20.0)

0.87

Resident information
Sex

Grade

Emergency department duty
 0 per month220

58 (26.4)

1 (reference) 1–2 per month909

218 (24.0)

0.85

0.60

1.19

0.33

 3–5 per month4205 843 (20.1)

0.70

0.51

0.96

0.02

 >6 per month611

149 (24.4)

0.86

0.61

1.22

0.39

 Unknown

31

9 (29.0)

0.97

0.52

1.80

0.91

 No experience with care of patients with COVID-­19759

162 (21.3)

1 (reference) Moderate experience with care of patients with COVID-­19 (1–10)

4273 894 (20.9)

0.99

0.89

1.11

0.89

 Well experience with care of patients with COVID-­19 (≥11 patients)

944

1.25

1.02

1.53

0.03

Care of patients with COVID-­19

221 (23.4)

PPE supply status Sufficient supply

5017 1011 (20.2)

1 (reference) Intermediate supply

611

157 (25.7)

1.31

1.15

1.51

<0.001 Insufficient supply

348

109 (31.3)

1.60

1.36

1.88

<0.001

Duty hour 0–59 hours per week

2517 520 (20.7)

1 (reference) 60–79 hours per week

2264 471 (20.8)

1.01

0.90

1.12

0.92

 >80 hours per week

1195 286 (23.9)

1.11

0.97

1.28

0.14

*Adjusted for all variables listed in the table using the multivariable modified Poisson regression model with cluster-­robust variance.
†High incidence area of COVID-­19 was defined as prefectures designated as endemic or non-­endemic areas by setting the median of the cumulative
number of patients with COVID-­19 between 1 April 2020 and 31 January 2021 as the cut-­off value.
aPR, adjusted prevalence ratio; PGY, postgraduate year; PPE, personal protective equipment.

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Table 2 Relationship between care of patients with COVID-­19 and burnout in resident physicians

Open access

95% CIn

Depression (%) aPR*

Lower limit Upper limit P value Quartile 1 (5 73 441–1 786 170)1513

459 (30.3)

1 (reference) Quartile 2 (1 815 865–3 700 305)1401

449 (32.1)

1.15

0.99

1.32

0.06

 Quartile 3 (5 101 556–7 483 128)1507

423 (28.1)

0.98

0.83

1.17

0.84

 Quartile 4 (8 839 469–13 515 271)1555

427 (27.5)

0.92

0.77

1.10

0.38

 No

1332

417 (31.3)

1 (reference)

 Yes

4644

1341 (28.9)

0.92

0.80

1.07

0.27

 Community-­based hospital

4996

1443 (28.9)

1 (reference) University branch hospital306

98 (32.0)

1.17

0.96

1.43

0.11

 University hospital674

217 (32.2)

1.11

0.96

1.25

0.16

 Designated medical institution for infectious disease

2487

740 (29.8)

1 (reference) Non-­designated medical institution for infectious disease3489

1018 (29.2)

1.00

0.92

1.10

0.92

 Male4064

1167 (28.7)

1 (reference) Female1912

591 (30.9)

1.07

0.99

1.16

0.08

 PGY-­13041

951 (31.3)

1 (reference) PGY-­22935

807 (27.5)

0.87

0.80

0.94

<0.001 0 per month220

77 (35.0)

1 (reference) 1–2 per month909

270 (29.7)

0.87

0.69

1.09

0.21

 3–5 per month4205

1209 (28.8)

0.86

0.70

1.04

0.11

 >6 per month611

192 (31.4)

0.96

0.76

1.21

0.72

 Unknown

31

10 (32.3)

0.90

0.52

1.55

0.69

 No experience with care of patients with COVID-­19759

234 (30.8)

1 (reference) Moderate experience with care of patients with COVID-­19(1–10)

4273

1235 (28.9)

1.00

0.92

1.09

0.96

 Well experience with care of patients with COVID-­19 (≥11
patients)

944

289 (30.6)

1.11

0.95

1.30

0.20

 Sufficient supply

5017

1418 (28.3)

1 (reference) Intermediate supply

611

206 (33.7)

1.18

1.06

1.31

0.002

 Insufficient supply

348

134 (38.5)

1.35

1.18

1.55

<0.001 0–59 hours per week

2517

734 (29.2)

1 (reference) 60–79 hours per week

2264

621 (27.4)

0.94

0.85

1.04

0.21

 >80 hours per week

1195

403 (33.7)

1.15

1.03

1.29

0.01

Prefecture information
Population

High incidence area of COVID-­19†

Hospital information
Type of hospitalCategory of infectious disease designated medical institution

Resident information
Sex

Grade

Emergency department duty

Care of patients with COVID-­19

PPE supply status

Duty hour*Adjusted for all variables listed in the table using the multivariable modified Poisson regression model with cluster-­robust variance.
†High incidence area of COVID-­19 was defined as prefectures designated as endemic or non-­endemic areas by setting the median of the cumulative
number of patients with COVID-­19 between 1 April 2020 and 31 January 2021 as the cut-­off value.
aPR, adjusted prevalence ratio; PGY, postgraduate year; PPE, personal protective equipment.

6

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Table 3 Relationship between care of patients with COVID-­19 and depression in resident physicians

Open access

95% CInHigh stress
(%)
aPR*

 Quartile 1 (573 441–1 786 170)1513

609 (40.3)

1 (reference) Quartile 2 (1 815 865–3 700 305)1401

557 (39.8)

1.00

0.88

1.14

0.97

 Quartile 3 (5 101 556–7 483 128)1507

596 (39.6)

0.97

0.85

1.11

0.67

 Quartile 4 (8 839 469–13 515 271)1555

580 (37.3)

0.89

0.77

1.02

0.08

 No

1332

522 (39.2)

1 (reference)

 Yes

4644

1820 (39.2)

1.03

0.91

1.18

0.62

 Community-­based hospital

4996

1909 (38.2)

1 (reference) University branch hospital306

130 (42.5)

1.18

0.99

1.42

0.06

 University hospital674

303 (45.0)

1.21

1.09

1.33

<0.001 Designated medical institution for infectious disease2487

988 (39.7)

1 (reference) Non-­designated medical institution for infectious disease3489

1354 (38.8)

0.99

0.92

1.07

0.81

 Male4064

1548 (38.1)

1 (reference) Female1912

794 (41.5)

1.09

1.02

1.17

0.011

 PGY-­1

3041

1246 (41.0)

1 (reference) PGY-­2

2935

1096 (37.3)

0.90

0.84

0.96

0.001

 0 per month220

95 (43.2)

1 (reference) 1–2 per month909

364 (40.0)

0.94

0.78

1.13

0.50

 3–5 per month

4205

1597 (38.0)

0.91

0.77

1.09

0.31

 >6 per month611

270 (44.2)

1.04

0.85

1.28

0.69

 Unknown

31

16 (51.6)

1.12

0.79

1.57

0.52

Lower limit Upper limit P value

Prefecture information
Population

High incidence area of COVID-­19†

Hospital information
Type of hospitalCategory of infectious disease designated medical institution

Resident information
Sex

Grade

Emergency department duty

Care of patients with COVID-­19 No experience with care of patients with COVID-­19759

308 (40.6)

1 (reference) Moderate experience with care of patients with COVID-­19 (1–10)

4273

1641 (38.4)

0.98

0.92

1.05

0.64

 Well experience with care of patients with COVID-­19 (≥11
patients)

944

393 (41.6)

1.00

0.87

1.14

0.94

 Sufficient supply

5017

1900 (37.9)

1 (reference) Intermediate supply

611

270 (44.2)

1.15

1.06

1.25

<0.001 Insufficient supply

348

172 (49.4)

1.27

1.13

1.43

<0.001 0–59 hours per week

2517

881 (35.0)

1 (reference) 60–79 hours per week

2264

913 (40.3)

1.15

1.07

1.24

<0.001 >80 hours per week

1195

548 (45.9)

1.29

1.18

1.42

<0.001

PPE supply status

Duty hour*Adjusted for all variables listed in the table using the multivariable modified Poisson regression model with cluster-­robust variance.
†High incidence area of COVID-­19 was defined as prefectures designated as endemic or non-­endemic areas by setting the median of the cumulative
number of patients with COVID-­19 between 1 April 2020 and 31 January 2021 as the cut-­off value.
aPR, adjusted prevalence ratio; PGY, postgraduate year; PPE, personal protective equipment.

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Table 4 Relationship between care of patients with COVID-­19 and high stress condition in resident physicians

Open accessnHigh jobsatisfaction (%) aPR*

95% CI
Lower limit Upper limit P value

Prefecture information
Population Quartile 1 (573 441–1 786 170)

1513 935 (61.8)

1 (reference) Quartile 2 (1 815 865–3 700 305)

1401 865 (61.7)

1.07

0.99

1.15

0.08

 Quartile 3 (5 101 556–7 483 128)

1507 951 (63.1)

1.10

1.01

1.20

0.01

 Quartile 4 (8 839 469–13 515 271)

1555 980 (63.0)

1.11

1.01

1.21

0.01

 No

1332 859 (64.5)

1 (reference) Yes4644 2872 (61.8)

0.88

0.81

0.95

<0.001 Community-­based hospital

4996 3181 (63.7)

1 (reference) University branch hospital306

173 (56.5)

0.91

0.79

1.05

0.19

 University hospital674

377 (55.9)

0.91

0.83

1.01

0.05

0.96

1.06

0.74

0.97

1.06

0.62

1.07

1.15

<0.001High incidence area of COVID-­19†

Hospital information
Type of hospitalCategory of infectious disease designated medical institution Designated medical institution for infectious disease2487 1559 (62.7)

1 (reference) Non-­designated medical institution for infectious disease3489 2172 (62.3)

1.01 Male4064 2538 (62.5)

1 (reference) Female1912 1193 (62.4)

1.01 PGY-­13041 1806 (59.4)

1 (reference) PGY-­22935 1925 (65.6)

1.11 0 per month220

132 (60.0)

1 (reference) 1–2 per month909

524 (57.7)

0.93

0.80

1.08

0.33

 3–5 per month4205 2679 (63.7)

0.99

0.86

1.14

0.89

 >6 per month611

384 (62.9)

0.95

0.81

1.11

0.52

 Unknown

31

12 (38.7)

0.65

0.41

1.01

0.05

759

472 (62.2)

Resident information
Sex

Grade

Emergency department duty

Care of patients with COVID-­19 No experience with care of patients with COVID-­19

1 (reference) Moderate experience with care of patients with COVID-­19 (1–10) 4273 2677 (62.7)

1.01

0.97

1.07

0.56

 Well experience with care of patients with COVID-­19 (≥11
patients)

1.08

0.99

1.16

0.05

944

582 (61.7)

PPE supply status Sufficient supply

5017 3209 (64.0)

1 (reference) Intermediate supply

611

341 (55.8)

0.87

0.81

0.94

<0.001 Insufficient supply348

181 (52.0)

0.80

0.72

0.90

<0.001

Duty hour 0–59 hours per week

2517 1539 (61.1)

1 (reference) 60–79 hours per week

2264 1437 (63.5)

1.03

0.98

1.08

0.22

 >80 hours per week

1195 755 (63.2)

1.02

0.96

1.08

0.48

*Adjusted for all variables listed in the table using the multivariable modified Poisson regression model with cluster-­robust variance.
†High incidence area of COVID-­19 was defined as prefectures designated as endemic or non-­endemic areas by setting the median of the cumulative
number of patients with COVID-­19 between 1 April 2020 and 31 January 2021 as the cut-­off value.
aPR, adjusted prevalence ratio; PGY, postgraduate year; PPE, personal protective equipment.

8

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Table 5 Relationship between COVID-­19 management and high job satisfaction in resident physicians

Open access

DISCUSSION
The current study has been the first to investigate therelationship between the care of patients with COVID-­19
and mental health conditions among postgraduate clinical resident physicians during the COVID-­19 pandemic
in Japan using nationwide data. Accordingly, our results
showed that approximately half of resident physicians
never experience the care of patients with COVID-­
19
in Japan and that burnout among resident physiciansslightly worsened as the number of experiencing care forpatients with COVID-­19 increased. Moreover, a significant
increase in depression, burnout and high stress condition
among resident physicians was observed when the supply
of PPE was inadequate.
A number of systematic reviews have shown that themental health of physicians and resident physicians worsened during the COVID-­19 pandemic.27 28 An umbrella
review showed that 40.3% of physicians experienced
depression during the pandemic, whereas 17%–19.8%
experienced anxiety.3 Several studies on resident mental
health in Japan, most of which were conducted before
the COVID-­
19 pandemic, have reported a 17%–33%
prevalence of resident physicians’ burnout29 30 and a
23%–29% prevalence of depression.31 32 However, only
one study on satisfaction with residency training reported
high satisfaction (58%),33 while no study has examinedwork-­
related stress during the COVID-­
19 pandemic.
Therefore, the pre-­COVID-­
19 pandemic mental statusindicated by the results of these studies is not clearly
different from the mental status of the residents in thisstudy who were trained during the COVID-­19 pandemic
in Japan. Moreover, our findings showed that burnout
only slightly increased in resident physicians who cared ahigh number of patients with COVID-­19. This study was
conducted in January 2021, during the ‘third wave’ of thepandemic in Japan and not when the pandemic was at its
nadir.34 It is possible that even during the peak period,
several resident physicians did not experience increased
workloads and were in a safe work environment, resulting
in limited impact on their mental health.
In this study, care of patients with COVID-­19 had a positive association with burnout but not with depression,stress or low job satisfaction in residents who cared formany patients with COVID-­19. In particular, the discrepancy between burnout and depression results may be due
to differences in their concepts. Burnout is a disorderthat results from the effects of long-­term occupational
stress with a corresponding lack of resources.6 Therefore,
it is quite possible that the risk of burnout increases if
the patients with COVID-­19 care results in heavy workloads. On the other hand, depression is a mental disorderthat is composed of multiple factors, including mental,
emotional, social and genetic.35 Furthermore, burnout
depends on the inability to cope with stress and it playsa central role in its aetiology, but depression is not necessarily caused by a single stress alone, such as overwork.36
Thus, in the present study, mental health of Japanese
resident physicians showed an association with burnout
caused bywork environment burden from COVID-­
19
patient care, but not depression, which is a psychiatricdisease.
Stepwise strategies to ensure that residents receive
effective training depending on epidemic situation
are needed. In response to the COVID-­
19 pandemic,
numerous resident physicians worldwide restricted
their rotations, resulting in the loss of essential learning
opportunities. For instance, surgical residents focusedon treating patients with COVID-­19 instead of surgicaltraining.37 38 In addition, many studies had reported
that several resident physicians and medical students
participated in COVID-­
19 examinations by changing
their original curriculum and graduating early.39 40 In
fact, a number of countries had adopted the strategy ofincluding even medical students into the clinical teamto support and maintain the health workforce capacity.10
However, approximately half of the resident physicians
included herein reported having never experienced
the care of patients with COVID-­19, although this study
was conducted during ‘third wave’ of the pandemic in
Japan. These results implied that resident physicians werein hospitals across Japan were subjected to human flow
control. In fact, keeping health workers on standby was
one approach to limit their exposure and prevent nosocomial infections.41 Moreover, adequate human resource
within hospitals is important for managing hospital careduring the pandemic. In Japan, the number of doctors
per population was lower than that in other developed
countries,42 with resident physicians potentially being animportant human resource. Therefore, to manage thepandemic with an ‘all hands on deck’ approach, introduction of strategies, such as guidelines for redeploymentof postgraduate trainees beyond their primary specialties
in the USA, need to be considered.43
Anxiety regarding inadequate PPE has been reported
to contribute significantly to resident physicians’ stress.44
The shortage of adequate PPE for front-­line healthcare
workers, including respirators, gloves, face shields, gowns
and hand sanitiser, had a negative effect on health.45 The
high infection and mortality rates experienced by healthcare workers had been partly due to the inadequate PPE,
which acts as a source of stress for resident physicians.
In situations where PPE is in short supply, resident physicians may be forced to prepare PPE at their own expense,
leading to increased stress and adverse mental healthoutcomes.46 47 Furthermore, inadequate education on
how to properly wear PPE can be a stressor for residents.48
The stressors associated with the COVID-­19 crisis can also
negatively influence residents’ ability to learn.44 Residency programmes should therefore consider the stress

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In online supplemental table 1, we showed the relationship between the number of experiencing care forpatients with COVID-­19 and the GM-­ITE Score. A higher
total GM-­ITE Score was associated with well-­experienced
with the care of patients with COVID-­19.

Open access
month) had the lowest prevalence of burnout. This result
suggested an optimal workload for protecting the mental
health among resident physicians. We previously haveanalysed the relationship between basic clinical competency and the number of ED duties in 11 244 Japanese
resident physicians. A moderate number of ED duties(3–5 per month) was most strongly associated with basic
clinical knowledge.24 We believe that there is an optimal
workload for both mental health and improvement ofclinical competency.
The current study has several limitations. First, thisstudy used simple instruments to determine mental
health. Given that this questionnaire was provided to theresident physicians immediately after the GM-­
ITE, wereduced the number of questions to account for theirburden. While the PHQ-­2 used to measure depression ishighly sensitive and specific for diagnosing depression,
this tool has only been used to screen for depression.16
Only one question was used to determine burnout inthe Mini-­Z 2.0 survey. Although this one question instrument has a high specificity for diagnosing burnout, it
has a rather low sensitivity, which may underestimate
the number of those residents experiencing burnout inthis study.19 20 Second, we did not collect information
regarding the resident physicians’ baseline psychiatricillnesses and personalities. It is possible that resident
physicians with depression or anxiety may avoid training
hospitals located in COVID-­19 endemic areas. Third, thenumber of experiencing care for patients with COVID-­19
was based on self-­reports by the residents, which may beinaccurate. In addition, given that only the number ofcases cared was asked, we could not determine whether
the period of responsibility was partial or total or whether
only observation was performed. Fourth, the current
study only selected participants from GM-­ITE, a voluntary programme, which may have introduced selection
bias. The participants of this study accounted for approximately one-­third of all resident physicians in Japan, andthe training hospitals participating in this study are thosemore committed to education. Fifth, this study was anobservational study involving resident physicians (PGY-­1
and PGY-­2) from 583 teaching hospitals across Japan.
Based on the experiences of patients receiving COVID-­19
care, research studies including senior doctors (classified
as PGY-­3 or above) could have higher clinical and social
implications. Sixth, one limitation could not be evaluatedusing our questionnaire survey for resident physicians. It
was impossible to distinguish whether the resident physicians actively examined the patients with COVID-­19 or
was forced to examine them. If only resident physicians
who were forced to examine patients with COVID-­19 were
included in the analysis, the results of the analysis might
have been different. The PR of burnout could have been
higher than 1.25. Seventh, the results of our multivariate
analyses showed that relatively sparsely populated areas(quartile 2) were significantly associated with burnout
and depression as shown in tables 2 and 3. We believethat the factor of social support could be hidden behind

10

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experienced by resident physicians, the negative impact
this has on their education, and steps to mitigate it.
The current study revealed the current status andchallenges of resident physicians’ education during the
COVID-­19 pandemic in Japan. First, our findings showedthat burnout among residents slightly worsened as thenumber of experiencing care for patients with COVID-­19
increased. A related factor that was particularly striking
was the shortage of PPE, which may help resident
physicians safely participate in the care of patients with
COVID-­19 by reducing their fear of contracting the virus.
Second, we found that only half of resident physicians inJapan were involved in the care of patients with COVID-­
19. This could have been attributed to the exclusion ofresident physicians from front-­line care in many hospitals perhaps due to the low level of clinical readiness ofJapanese resident physicians.49 Despite the shortage of
medical personnel during the pandemic, medical institutions may have weighed infection control concerns
against the usefulness of their workforce and opted forsafety. Third, the lack of resident physicians’ participationin the care of patients with COVID-­19 may have negatively
impacted education of resident physicians. Indeed, thecurrent study showed that those with less experience inthe care of patients with COVID-­19 had lower scores on
the in-­training examination (online supplemental table1). Given the expected long-­term impact of the pandemic,
it is important that resident physicians participate in thecare of patients with COVID-­19 and receive training. It
would be desirable for all resident physicians in Japan to
be more actively trained in COVID-­19 while consideringboth mental health and infection control.
Burnout consists of a condition of physical, mental
and EE. In general, female physicians tend to experiencehigher levels of burnout than male physicians.50–52 It isdifficult for female physicians to balance personal life,
such as childbirth and childcare, and professional career.
Female physicians experience difficulties to be successful
in both personal and professional lives. As a result, female
physicians may have higher levels of EE than male physicians.53 On the other hand, our study results showed ahigher prevalence of burnout among male physicians
than among female physicians. We speculated that theextraordinary circumstance of the COVID-­19 pandemic
modified study’s results.
Our results showed that PGY-­1 resident physicians had ahigher prevalence of burnout and depression than PGY-­2
resident physicians. PGY-­1 resident physicians may have ahigher stress level than PGY-­2 resident physicians generally. The PGY-­
1 resident physicians have less medical
knowledge and skills and clinical experience than PGY-­2
resident physicians.54 In addition, PGY-­1 resident physicians are more likely to feel stressed in terms of their
responsibility for patients’ management. Previous studies
have shown ta higher risk of burnout related to both roleambiguity and low levels of decision latitude.55 56
As shown in table 2, we have found that resident physicians with a moderate number of ED duties (3–5 per

Open access

CONCLUSIONSThe current study found that prevalence of burnout
slightly increased in resident physicians who cared a highnumber of patients with COVID-­19. Approximately half ofthe resident physicians in Japan did not participate in thecare of patients with COVID-­19, which posed a challenge
from an educational perspective. Facilitating training in
the care of patients with COVID-­19 is important for theestablishment of a sustainable medical system during the
pandemic.
Author affiliations
1
Division of Medical Education, Juntendo University School of Medicine, Tokyo,
Japan
2
Department of Internal Medicine, Mito Kyodo General Hospital, University ofTsukuba, Ibaraki, Japan3
Department of General Medicine, Chiba University Hospital, Chiba, Japan
4
Department of Patient Safety, Nagoya University Hospital, Aichi, Japan
5
Department of Information and Computer Technology, Faculty of Engineering, Tokyo
University of Science, Tokyo, Japan
6
Department of Diagnostic and Generalist Medicine, Dokkyo Medical University
Hospital, Tochigi, Japan
7
Division of General Medicine, Center for Community Medicine, Jichi Medical
University, Tochigi, Japan
8
Department of Emergency and General Medicine, Kyorin University, Tokyo, Japan
9
Department of General Internal Medicine, Shonan Kamakura General Hospital,
Kanagawa, Japan
10
Division of General Internal Medicine, Department of Internal Medicine, St.
Marianna University School of Medicine, Kanagawa, Japan
11
Muribushi Okinawa Center for Teaching Hospitals, Okinawa, Japan
12
Tokyo Foundation for Policy Research, Tokyo, Japanthe JAMEP lecture. TShimizu, YY, KS and SF received an honorarium from JAMEP as
exam preparers of GM-­ITE.
Patient and public involvement Patients and/or the public were not involved in
the design, or conduct, or reporting, or dissemination plans of this research.
Patient consent for publication Not applicable.
Ethics approval This study was approved by the Ethics Review Board of JAMEP(approval number 21-­9).
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data are available upon reasonable request. Resident
physicians who joined in this study did not obtain consent for their data to beshared publicly, so supporting data is not available. The corresponding author will
respond to inquiries on the data analyses in this study.
Supplemental material This content has been supplied by the author(s). It has
not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been
peer-­reviewed. Any opinions or recommendations discussed are solely thoseof the author(s) and are not endorsed by BMJ. BMJ disclaims all liability andresponsibility arising from any reliance placed on the content. Where the content
includes any translated material, BMJ does not warrant the accuracy and reliabilityof the translations (including but not limited to local regulations, clinical guidelines,
terminology, drug names and drug dosages), and is not responsible for any error
and/or omissions arising from translation and adaptation or otherwise.
Open access This is an open access article distributed in accordance with theCreative Commons Attribution Non Commercial (CC BY-­NC 4.0) license, which
permits others to distribute, remix, adapt, build upon this work non-­commercially,and license their derivative works on different terms, provided the original work is
properly cited, appropriate credit is given, any changes made indicated, and the use
is non-­commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.
ORCID iDs
Yuji Nishizaki http://orcid.org/0000-0002-6964-6702
Kiyoshi Shikino http://orcid.org/0000-0002-3721-3443
Masaru Kurihara http://orcid.org/0000-0001-9195-4202
Tomohiro Shinozaki http://orcid.org/0000-0003-3395-9691
Sho Fukui http://orcid.org/0000-0002-3082-1374
Sho Nishiguchi http://orcid.org/0000-0002-0060-0714
Yasuharu Tokuda http://orcid.org/0000-0002-9325-7934

REFERENCES

Competing interests YN received an honorarium from JAMEP as a GM-­ITE project
manager. YT is the JAMEP director, and he received an honorarium from JAMEP asa speaker of the JAMEP lecture. TShinozaki received an honorarium from JAMEP asa statistical adviser. HK and KS received an honorarium from JAMEP as speakers of

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Twitter Yasuharu Tokuda @yasuharutokuda
Acknowledgements We thank members of JAMEP for their assistance and
Dr Narimasa Katsuta (department of psychiatry, Juntendo University Faculty of
Medicine) for psychiatric expertise. The authors would like to thank Enago (www.​enago.jp) for the English language review.
Contributors Study concept and design: YN and YT. Acquisition, analysis orinterpretation of data: TShinozaki, KKataoka, TShimizu, YY, SF, SN and KKatayama.
Manuscript drafting: YN, KN, KS and MK. Critical revision of the manuscript forimportant intellectual content: YN, HK and YT. Statistical analysis: TS and KK.
Administrative, technical or material support: YN and YT. Supervision: YN, HK and YT.
TShinozaki had full access to all of the data in the study and takes responsibility forthe integrity of the data and the accuracy of the data analysis. YN is guarantor.
Funding This work was supported by the Health, Labor and Welfare Policy Grantsof Research on Region Medical (21IA2004) from the Ministry of Health, Labor andWelfare.

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these results. Although we did not evaluate the relationship between the support system and mental health statein the present study, we believe that social support was
related to burnout and depression in resident physicians.
An abundant support system helps resident physicians toprotect their mental health, and a lower level of social
support is significantly associated with burnout.57 Moreover, a previous study had reported that physicians from
relatively sparsely populated areas, such as small cities,
had less social support from supervisors, family andfriends than those from a large city, town and village.58

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