NCHS Data Brief ■ No. 77 ■ November 2011

U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES

Centers for Disease Control and Prevention

National Center for Health Statistics

Physician Assistant and Advance Practice Nurse Care in 

Hospital Outpatient Departments: United States, 2008–2009

Esther Hing, M.P.H. and Sayeedha Uddin, M.D., M.P.H.

Key findings

•	 Hospital outpatient

department visits attended only

by physician assistants (PAs)

or advance practice nurses

(APNs) increased by 50% from

2000–2001 (10%) through

2008–2009 (15%).

•	 The more urban the

hospital location, the lower the

percentage of visits seen only

by PAs or APNs; decreasing

from 36% in nonmetropolitan

areas to 6% in large central

metropolitan areas.

•	 A higher percentage of

PA- or APN-only visits were

to general medicine (21%) and

obstetric or gynecology (19%)

clinics compared with pediatric

(8%) and surgical (5%) clinics.

•	 PAs and APNs saw a higher

percentage of visits where a

new problem was the major

reason for the visit (22%)

compared with visits for a

chronic condition [routine

(11%) or flare-up (14%)], or

pre- or postsurgery care (6%).

Physician assistants (PAs) are state-licensed health professionals practicing

medicine under a physician’s supervision (1,2). Advance practice nurses

(APNs) are registered nurses (RNs) with advanced training. PAs and APNs

have been expanding in supply and playing increasingly diversified roles in

the U.S. health care system (1–3). Nationwide, there were 80,000 PAs and

250,000 APNs in 2008. The majority of APNs are nurse practitioners (NPs)

(3). In 2008, 38% of NPs, 58% of nurse midwives (NMs), another type of

APN, and 23% of PAs worked in hospital settings (1,3).

Keywords: nonphysician clinicians • hospital outpatient department visits

Are PAs and APNs providing more care at visits to hospital 

OPDs? 

•	 Between 2000–2001 and 2008–2009, the percentage of hospital OPD

visits seen only by a PA or APN increased from 10% to 15% of OPD

visits, while the percentage of joint physician/nonphysician clinician

visits remained about 3% (Figure 1).

Figure 1. Hospital outpatient department visits where a PA or APN was seen with or without a 

physician present: United States, 2000–2009

1

Time trend is statistically significant (p < 0.05).

NOTES: PA is physician assistant. APN is advance practice nurse and includes nurse practitioners and nurse midwives. Combined 

data presented reflect average annual estimates for each 2-year period. 

SOURCE: CDC/NCHS, National Hospital Ambulatory Medical Care Survey.

0

5

10

15

20 Physician and PA or APN

PA or APN only1

2000–2001 2002–2003 2004–2005 2006–2007 2008–2009

Percent of visits

Year

3 2

3

4

3

15 13

10 11 10
NCHS Data Brief ■ No. 77 ■ November 2011

■  2  ■

•	 Three-fourths of 103,010,000 hospital OPD visits in 2008–2009 were seen by a physician

and 18% were seen by a PA or APN (4,5). Among visits to PAs or APNs, 65% were seen by

an APN and 35% were seen by a PA (data not shown).

•	 During the same time period, the percentage of OPD visits attended only by physicians

declined from 77% in 2000–2001 to 72% in 2008–2009 (data not shown).

•	 The percentage of visits not seen by a physician, PA, or APN remained the same (10%) and

was excluded from the analyses that follow.

Does PA/APN utilization differ by selected hospital characteristics?

•	 The percentage of visits attended only by a PA or APN decreased as hospital size (number

of beds) increased, from 24% among OPDs in hospitals with under 200 beds to 10% among

hospitals with 400 or more beds.

•	 The percentage of visits seen only by a PA or APN was higher in nonteaching hospital OPD

clinics (22%) than in teaching hospital OPD clinics (8%) (Figure 2).

Figure 2. Type of provider seen, by hospital characteristics: United States, 2008–2009

1

Type of provider is significantly associated with hospital size ( 2 = 3.8, df = 3, p < 0.01). 2

Type of provider is significantly associated with teaching hospital status ( 2 = 10.4, df = 2, p < 0.01).

NOTES: PA is physician assistant. APN is advance practice nurse and includes nurse practitioners and nurse midwives. Visits that did not involve a physician, PA,

or APN are excluded. Physician visits where a PA or APN was also present (4%) are included with physician visits. See “Data source and methods” for more details.

SOURCE: CDC/NCHS, National Hospital Ambulatory Medical Care Survey.

Hospital size1

Teaching hospital status2

0 20 40 60 80 100

PA or APN only

Physician

Nonteaching hospital

Teaching hospital

400 beds

or more

200–399

beds

Fewer than

200 beds

Percent of visits

76

24

87

13

90

10

92

8

78

22
NCHS Data Brief ■ No. 77 ■ November 2011

■  3  ■

Does PA/APN utilization differ by hospital location?

•	 The percentage of visits seen solely by a PA or APN decreased as the hospital’s location

became increasingly more urban: from 36% in nonmetropolitan areas to 6% in large central

metropolitan areas (Figure 3).

Figure 3. Type of provider seen, by hospital location: United States, 2008–2009

NOTES: Type of provider is significantly associated with metropolitan status ( 2 = 10.4, df = 3, p < 0.01). PA is physician assistant. APN is advance practice nurse

and includes nurse practitioners and nurse midwives. Visits that did not involve a physician, PA, or APN are excluded. Physician visits where a PA or APN was

also present (4%) are included with physician visits. See “Data source and methods” for more details.

SOURCE: CDC/NCHS, National Hospital Ambulatory Medical Care Survey.

Percent of visits

94

6

86

14

81

19

64

36

Nonmetropolitan

Small or medium

metropolitan

Large fringe

metropolitan

Large central

metropolitan

0 20 40 60 80 100

PA or APN only

Physician

In which types of clinics are PAs and APNs practicing? 

•	 The percentage of visits seen only by a PA or APN was higher in general medicine (21%)

and obstetrics and gynecology (19%) clinics than in pediatric (8%) and surgical (5%) clinics

(Figure 4).

What types of visits were seen by PAs or APNs? 

•	 PAs and APNs saw a higher percentage of visits where a new problem was the major reason

for the visit (22%) compared with visits for a chronic condition [routine (11%) or flare-up

(14%)], or pre- or postsurgery care (6%) (Figure 5).

•	 PAs and APNs saw a higher percentage of preventive care visits (17%) compared with visits

for a routine chronic condition or pre- or postsurgery care.

•	 The percentage of visits seen only by a PA or APN was higher in OPD clinics reported to be

the patients’ primary care provider (22%) than in those clinics not identified as the patients’

primary care provider (13%).
NCHS Data Brief ■ No. 77 ■ November 2011

■  4  ■

Figure 4. Type of provider seen, by type of clinic: United States, 2008–2009 

* Figure does not meet standards of reliability or precision.

1

Difference with general medicine clinic is statistically significant (p < 0.05). 2

Difference with obstetrics or gynecology clinic is statistically significant (p < 0.05).

NOTES: PA is physician assistant. APN is advance practice nurse and includes nurse practitioners and nurse midwives. Visits that did not involve a physician, PA,

or APN are excluded. Physician visits where a PA or APN was also present (4%) are included with physician visits. See “Data source and methods” for more details.

SOURCE: CDC/NCHS, National Hospital Ambulatory Medical Care Survey.

0 20 40 60 80 100

Substance abuse

and other

Surgical

Pediatrics

Obstetrics or

gynecology

General medicine

PA or APN only

Physician

79

21

81

19

92

1,28

95

1,25

91

9*

Percent of visits

Figure 5. Type of provider seen, by type of visit: United States, 2008–2009

1

Difference with new problem visits is statistically significant (p < 0.05). 2

Difference with preventive care visits is statistically significant (p < 0.05). 3

Difference with nonprimary care provider visits is statistically significant (p < 0.05). 

NOTES: PA is physician assistant. APN is advance practice nurse and includes nurse practitioners and nurse midwives. Visits that did not involve a physician, PA,

or APN are excluded. Physician visits where a PA or APN was also present (4%) are included with physician visits. See “Data source and methods” for more details.

SOURCE: CDC/NCHS, National Hospital Ambulatory Medical Care Survey.

PA or APN only

Physician

No

Yes

Pre- or

postsurgery

Chronic condition,

routine

Chronic condition,

flare-up

Preventive

care

New

problem

0 20 40 60 80 100

Percent of visits

78

83

86

89

94

78 3

22

87

13

22

17

1

14

1,211

1,26

Major reason for visit

Visit is to primary 

care provider
NCHS Data Brief ■ No. 77 ■ November 2011

■  5  ■

Does the type of provider seen vary by patient characteristics? 

•	 A higher percentage of visits made by younger patients were seen only by PAs or APNs (19%)

than were older patients 3%).	This	pattern 

Table).

•	 A lower percentage of visits by non-Hispanic black patients (12%) than non-Hispanic white

patients (18%) were seen solely by a PA or APN.

•	 PAs and NPs saw significantly higher percentages of visits by patients with Medicaid or the

Children’s Health Insurance Plan (18%) or no insurance (22%) compared with visits made by

Medicare patients (12%).

Table. Type of provider seen, by patient characteristics: United States, 2008–2009

Selected characteristic Physician PA or APN only

Total 100 100

Sex, age in years

All, under 45 81 119

All, 45 and over 87 13

Female, under 45 80 120

Female, 45 and over 86 14

Male, under 45 83 117

Male, 45 and over 88 12

Race/ethnicity

Non-Hispanic white 82 18

Non-Hispanic black 88 2

12

Hispanic 85 15

Other 85 15

Primary expected payment source

Private insurance 84 16

Medicare, including dually eligible 88 12

Medicaid or Children’s Health Insurance Program 92 3

18

Uninsured 78 3

22

Other 86 14

1

Difference by age is statistically significant. 2

Difference with non-Hispanic white persons is statistically significant. 3

Difference with Medicare visits is statistically significant.

NOTES: Data are shown as percentages. PA is physician assistant. APN is advance practice nurse and includes nurse practitioners (NPs) and nurse midwives. 

Physician visits where a PA or APN was also present (4%) were considered physician visits. Visits that do not involve a physician, PA, or NP are excluded. See

“Data source and methods” for more details. 

SOURCE: CDC/NCHS, National Hospital Ambulatory Medical Care Survey. 

Summary 

This analysis shows that visits to PAs or APNs have become more common in hospital OPDs

over the past decade. Several of the 2008–2009 findings are consistent with previous studies. For

example, visits seen only by a PA or APN continue to be higher in rural areas (6,7). In addition, a

higher proportion of visits to PAs or APNs occur with younger patients (7).

This analysis uncovered some new findings about PAs or APNs in hospital OPDs. Visits to PAs or

APNs are more common in nonteaching hospitals and in smaller hospitals. General medical and
NCHS Data Brief ■ No. 77 ■ November 2011

■  6  ■

obstetrics or gynecology clinics have higher percentages of PA or APN visits than either pediatric

or surgery clinics. PAs or APNs in hospital OPDs provide services to patients for whom the clinic

serves as a primary care provider and for assessing new problems or provision of preventive care.

PAs or APNs are providing an increasing share of care delivered in OPDs compared with the

previous decade. The findings in this report suggest that PAs or APNs continue to provide a

critical health care function by providing care in settings with fewer physicians, such as rural

locations, small hospitals, and nonteaching hospitals.

Definitions

APN: Refers to an RN with advanced training in areas not usual for RNs, such as diagnosing

and managing common diseases, ordering tests, and prescribing medications. Although there are

several types of APNs, most APNs who work in OPDs are nurse practitioners or nurse midwives.

Therefore, in this report, the term APN refers specifically to NPs or NMs. Among the two types of

APNs not included in this report [nurse anesthetists (NAs) and clinical nurse specialists (CNSs)],

82% of NAs and 49% of CNSs worked in hospital settings in 2008 (3). Nationwide, NAs

comprised 13% and CNSs comprised 23% of all APNs in 2008 (3).

Hospital outpatient department: Refers to a hospital facility where nonemergent ambulatory

medical care is provided under the supervision of a physician.

Hospital size: Refers to the number of inpatient beds as recorded in SDI Market Profile Database.

Teaching hospital: Refers to a hospital that provides clinical education and training to current and

future doctors, nurses, and other health professionals, in addition to delivering medical care to

patients. Information on teaching hospital status is from SDI Market Profile Database.

Urban or rural classification of the hospital’s ZIP code: Developed by the Centers for Disease

Control and Prevention’s (CDC) National Center for Health Statistics (NCHS) to study the

association between urbanicity and health and to monitor the health of urban and rural residents.

The six-level classification scheme is based on county or county equivalents. Large central 

metropolitan includes counties in a metropolitan statistical area (MSA) of 1 million or more

population that contain the entire population of the largest principal city of the MSA, or whose

entire population resides in the largest principal city of the MSA, or that contain at least 250,000

of the population of any principal city in the MSA. Large fringe metropolitan includes counties in

an MSA of 1 million or more population that do not qualify as large central metropolitan. Medium 

metropolitan includes counties in an MSA of 250,000–999,999 population. Small metropolitan

includes counties in an MSA of 50,000–249,999 population. A rural or nonmetropolitan area

includes all counties that are outside of MSAs (8).

Data source and methods

All estimates are from the 2008 and 2009 National Hospital Ambulatory Medical Care Survey

(NHAMCS), an annual nationally representative survey of visits to nonfederal, general, and

short-stay hospital emergency and OPDs. The sampling frame for both the 2008 and 2009

NHAMCS were constructed from SDI’s “Healthcare Market Index, Updated July 15, 2006” and

“Hospital Market Profiling Solution, Second Quarter, 2006.” The OPD visit response rate was
NCHS Data Brief ■ No. 77 ■ November 2011

■  7  ■

75% in 2008 and 73% in 2009. More details about NHAMCS methodology are available (9,10).

OPD data in this study were limited to visits seen by a physician, PA, or APN (n = 59,165), of

which 52,718 were seen by a physician (including 3,016 seen by both physician and PA or APN)

and 6,447 were seen only by PAs or APNs. An estimated 10% of visits in 2008–2009 did not

involve a physician, PA, or APN (n = 8,294) and were attended by an RN or licensed practical

nurse, mental health provider, or some other provider. These visits were excluded from this report

because they differed in character from physician, PA, and APN visits. In this report, missing

information (weighted) for the following characteristics were not shown: hospital size (0.1%),

teaching hospital status (0.2%), major reason for visit (1.3%), whether clinic was a patient’s

primary care provider (8.9%), and type of provider seen (1.1%).

Data analyses were performed using the statistical packages SAS version 9.2 (SAS Institute, Cary,

N.C.) and SUDAAN version 9.0 (Research Triangle Institute, Research Triangle Park, N.C.).

Differences by type of provider and selected patient and visit characteristics were examined using

t tests for differences in percentages and chi-square tests for differences in percent distributions

at the p = 0.05 level. A weighted least-squares regression analysis was used to determine the

significance of trends by year, hospital size, and location.

About the authors

Esther Hing and Sayeedha Uddin are with CDC’s NCHS, Division of Health Care Statistics.

References

1.	 Cunningham R. Tapping the potential of the health care workforce: Scope-of-practice and

payment policies for advanced practice nurses and physician assistants. National Health Policy

Forum, Background Paper No. 76. The George Washington University: Washington, DC. 2010.

2.	 Paradise J, Dark C, Bitler N. Improving access to adult primary care in Medicaid: Exploring

the potential role of nurse practitioners and physician assistants. Kaiser Commission on Medicaid

and the Uninsured, Issue Paper. The Henry J. Kaiser Family Foundation: Washington, DC. 2011.

3.	 U.S. Department of Health and Human Services, Health Resources and Services

Administration. The registered nurse population: Findings from the 2008 National Sample Survey

of Registered Nurses. 2010.

4.	 NCHS. National Hospital Ambulatory Medical Care Survey: 2008 outpatient department

summary tables. Available from: http://www.cdc.gov/nchs/ahcd/web_tables.htm#2008.

5.	 NCHS. National Hospital Ambulatory Medical Care Survey: 2009 outpatient department

summary tables. In preparation.

6.	 Larson EH, Palazzo L, Berkowitz B, Pirani M, Hart G. The contribution of nurse practitioners

and physician assistants to generalist care in Washington state. Health Serv Res 38(4):1033–50.

2003.

7.	 McCaig LF, Hooker RS, Sekscenski ES, Woodwell DA. Physician assistants and nurse

practitioners in hospital outpatient departments, 1993–1994. Public Health Rep 113(1):75–82.

1998.
NCHS Data Brief ■ No. 77 ■ November 2011

U.S. DEPARTMENT OF

HEALTH & HUMAN SERVICES

Centers for Disease Control and Prevention

National Center for Health Statistics

3311 Toledo Road

Hyattsville, MD 20782

OFFICIAL BUSINESS 

PENALTY FOR PRIVATE USE, $300

FIRST CLASS MAIL 

POSTAGE & FEES PAID 

CDC/NCHS

PERMIT NO. G-284

8.	 National Center for Health Statistics. 2006 NCHS urban-rural

classification scheme for counties. Available from: http://www.cdc.gov/nchs/

data_access/urban_rural.htm.

9.	 National Center for Health Statistics. National Hospital Ambulatory

Medical Care Survey. Public-use data file documentation. 2008. Available

from: http://www.cdc.gov/nchs/ahcd/ahcd_questionnaires.htm.

10.	National Center for Health Statistics. National Hospital Ambulatory

Medical Care Survey. Public-use data file documentation. 2009. Available

from: http://www.cdc.gov/nchs/ahcd/ahcd_questionnaires.htm.	

Suggested citation

Hing E, Uddin S. Physician assistant and

advance practice nurse care in hospital

outpatient departments: United States,

2008–2009. NCHS data brief, no 77.

Hyattsville, MD: National Center for Health

Statistics. 2011.

Copyright information

All material appearing in this report is in

the public domain and may be reproduced

or copied without permission; citation as to

source, however, is appreciated.

National Center for Health 

Statistics

Edward J. Sondik, Ph.D., Director

Jennifer H. Madans, Ph.D., Associate 

Director for Science

Division of Health Care Statistics

Clarice Brown, M.S., Acting Director

For e-mail updates on NCHS publication 

releases, subscribe online at: 

http://www.cdc.gov/nchs/govdelivery.htm.

For questions or general information about 

NCHS: Tel: 1–800–232–4636

E-mail: cdcinfo@cdc.gov

Internet: http://www.cdc.gov/nchs

ISSN 1941–4927 (Print ed.)

ISSN 1941–4935 (Online ed.)

DHHS Publication No. (PHS) 2012–1209

CS227790