Can Massage During One Year Improve Health in Health-care Providers Working in Hospital
Phase: NA
Conditions: Massage Therapy, Health-care Workers, Quality of Life, Psychological Distress
Sponsor: University Hospital, Linkoeping

Study Protocol and Statistical analysis plan 
 
Can Massage During One Year Improve Health in Health-care 
Providers Working in Hospital 
 
 
NCT: 05555082  
 
Date: 2025-10-17 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 
Study design.  
This study used an embedded mixed methods pre-post design, where qualitative data were 
collected at the final follow-up to complement and help interpret quantitative finding 1. A 
mixed-methods approach combines quantitative and qualitative data to explore a 
phenomenon more comprehensively, allowing statistical trends (quantitative) to be explained 
through qualitative insights and qualitative findings to complement or expand quantitative 
results 1. The embedded design is flexible and adaptable, making it valuable for complex 
research questions where both numerical and narrative insights are needed. Quantitative 
data were prioritized to appraise limited efficacy, defined under Bowen’s feasibility framework 
as a preliminary within group assessment of the direction and magnitude of change, and to 
assess acceptability indicators including recruitment , adherence, and participant satisfaction 
2 . Qualitative data were collected at 12 months to deepen understanding of participants’ 
experiences 1 . Integration occurred during analysis by comparing qualitative themes with 
quantitative outcomes to examine convergence and divergence, with details provided in the 
Results and the Discussion. 
 
Participants 
While the literature reviewed in the introduction refers to (HCW) broadly, our sample was 
limited to registered and assistant nurses. This focus reflects the reality of the inpatient ward 
setting, where these professionals are most exposed to physically and emotionally 
demanding conditions, including shift work and close patient contact. Thus, registered and 
assistant nurses working in a medical ward at a Swedish hospital were eligible to participate 
in the study. To be included, participants needed to work in patient care at the ward for at 
least 50% of full-time hours. Approximately 130 nurses were estimated to meet the eligibility 
criteria, and we planned to recruit 50 nurses. The sample size was pragmatically based on 
operational capacity and resource availability, for example available funding only allowing us 
to offer a limited number of massage sessions. In addition, the number was considered 
reasonable to assess feasibility parameters such as recruitment yield, adherence, and 
acceptability, in line with Bowen et al. (2009) 2. While not statistically powered, the target was 
selected to support interpretation of feasibility outcomes. Recruitment was scheduled for a 
one-month period (November–December 2022) before the planned start of the intervention in 
January 2023. To raise awareness ahead of this short recruitment window, information about 
the upcoming study was shared with staff during routine staff meetings prior to the formal 
registration period. Recruitment was then carried out through an advertisement on the clinic's 

website and an email sent to all healthcare staff at the clinic. The recruitment email was 
directed specifically to the clinic’s nursing staff, in accordance with internal mailing list 
structures. Other professional groups, such as physicians, physiotherapists, or social 
workers, were not contacted and were not eligible to participate. Both the advertisement and 
the email provided detailed information about the study, including the maximum number of 
participants (50), and included a link to a registration form for those interested. The form 
collected participants' names, phone numbers, and email addresses. 
Individuals who registered and meet the inclusion criteria were emailed and invited to meet 
with the research nurse. During the appointment, participants had the opportunity to ask the 
nurse additional questions about the study and were asked to provide written consent for 
participation. At the visit baseline measures were obtained, including blood pressure, height, 
and weight, together with the baseline questionnaires. 
The intervention 
The participants received classic massage in 30-minute sessions approximately once a 
month over the course of one year (i.e., 2023). This duration was based on the standard 
hands-on treatment time offered by the certified massage therapists contracted for the study. 
Massage sessions were scheduled outside of working hours in agreement between each 
participant and the therapist and took place in a quiet and private room at a massage clinic to 
support relaxation. 
Two certified massage therapists were engaged for the study, and participants were evenly 
divided between them. Each participant received all their sessions from the same therapist to 
promote continuity and individual adaptation of the treatment. Both therapists were certified 
in classic Swedish massage and had 15 and 21 years of experience operating private 
massage practices. The treatment followed the principles of classic massage, including 
kneading, gliding, and tapping techniques, and primarily targeted areas commonly affected 
by work-related strain, such as the back, shoulders, and neck. The depth and focus of the 
massage were tailored to individual needs through ongoing dialogue with each participant. 
Because ward operations and summer vacations were expected to potentially reduce 
availability in June and July, the protocol allowed rescheduling across adjacent months; no 
blanket pause was planned. The target total exposure per participant was 10 to 12 sessions 
within twelve months, depending on individual scheduling. No exclusion criteria were set 
based on exact month-to-month spacing. 
 
Data collection 

Data was collected at three time points: baseline, 6 months, and at the end of the massage 
intervention after 12 months. Baseline data were collected at the initial appointment with the 
research nurse. Prior to this appointment, participants received a package of questionnaires 
to complete at home, which they returned during the visit. This procedure allowed 
participants time to reflect on the questions while ensuring that the completed forms could be 
checked for completeness or clarified during the appointment. These questionnaires covered 
background variables and outcome variables of interest (i.e., stress, mental health, sleeping 
problems, physical activity, HR-QoL and work ability). Participants were provided with a 
stamped envelope to return the completed questionnaires, either by handing them to the 
research nurse or by mailing them to the project leaders at the clinic, PJ or LE. At the 6-
month follow-up, participants completed the same set of questionnaires as at baseline which 
included questions about the number of massage sessions they attended, as well as 
questions about stress, mental health, sleep problems, HR-QoL, and work ability. At the end 
of the intervention at 12 months (December 2023–January 2024), participants again 
completed the same set of questionnaires, along with additional items on physical activity, 
satisfaction, and open-ended questions. On this occasion, they also rated their physical 
activity and scored their satisfaction with the massage on a scale, as well as responded to 
open-ended questions, allowing for the collection of both quantitative and qualitative data at 
12 months-follow-up. 
 
Feasibility outcomes 
Limited efficacy  
The quantitative outcome measures were collected to explore such early signals of effect, 
assess the relevance and sensitivity of the instruments used, and inform the design of a 
future fully powered trial. This does not imply low effectiveness, but rather a structured 
exploration of whether further testing is warranted 2. 
Quantitative data collection 
Stress 
Stress levels were evaluated using the Perceived Stress Scale-10 (PSS-10)3. The 
questionnaire consists of 10 items that assess how unpredictable, uncontrollable, and 
overloaded respondents find their lives. Participants rate each item on a 5-point Likert scale, 
ranging from 0 (never) to 4 (very often), reflecting their feelings and thoughts during the past 
month. The scores for the PSS-10 range from 0 to 40, with higher scores indicating higher 

perceived stress. The PSS-10 has been validated in Swedish  and is considered a reliable 
indicator of perceived stress 4. 
 
Mental Health 
We employed three different questionnaires to assess various aspects of mental health: the 
Patient Health Questionnaire-9 (PHQ-9)5 for depressive symptoms, the General Anxiety 
Disorder Scale-9 (GAD-7)6 for anxiety, and the Karolinska Exhaustion Disorder Scale (KEDS) 
7 for exhaustion.  
PHQ-9 consists of nine questions aligned with the diagnostic criteria for major depressive 
disorder in the DSM-IV5.  Each question is scored on a scale from 0 (not at all) to 3 (nearly 
every day), considering the frequency of symptoms over the past two weeks. The total score, 
ranging from 0 to 27, helps gauge the severity of depression, with higher scores indicating 
more severe depressive symptoms. The cut-off scores for PHQ-9 are as follows: Minimal 
depression ranges from 0 to 4, mild depression from 5 to 9, moderate depression from 10 to 
14, moderately severe depression from 15 to 19, and severe depression from 20 to 27. A 
≥20% reduction from baseline is typically used to indicate a clinically meaningful 
improvement in depressive symptoms 5.   
 GAD-7 6 comprises seven questions, each rated on a scale from 0 (not at all) to 3 (nearly 
every day), reflecting the frequency of anxiety symptoms over the past two weeks. The total 
score ranges from 0 to 21, with higher scores indicating greater anxiety severity. The cut-off 
scores for GAD-7 are as follows: minimal anxiety ranges from 0 to 4, mild anxiety from 5 to 9, 
moderate anxiety from 10 to 14, and severe anxiety from 15 to 21. A 4-point reduction has 
been suggested as the threshold for minimum clinically important difference (MCID)8. 
Sleep problems 
The Insomnia Severity Index (ISI) 9 assessed the severity of both nighttime and daytime 
components of insomnia. It consists of seven items that evaluate the nature, severity, and 
impact of insomnia over the past two weeks. Each item is rated on a 5-point Likert scale 
ranging from 0 (no problem) to 4 (very severe problem), with the total score ranging from 0 to 
28. Higher scores on the ISI indicate greater severity of insomnia symptoms. The cut-off 
scores for interpreting the ISI are as follows: scores from 0 to 7 indicate no clinically 
significant insomnia; scores from 8 to 14 suggest subthreshold insomnia; scores from 15 to 
21 reflect clinical insomnia of moderate severity; and scores from 22 to 28 indicate severe 
clinical insomnia. For ISI, two MCID thresholds have been proposed based on different 
outcome anchors. A 6-point reduction is commonly used to indicate clinically meaningful 

improvement in individuals with primary insomnia 10. However, smaller changes around 2.5 
points have also been associated with meaningful improvements in functioning and mood in 
non-clinical populations 10. In this study, we report the proportion of participants meeting both 
thresholds to provide a range of interpretive perspectives, recognizing the non-clinical nature 
of our sample. 
Health-related quality of life 
The RAND-36 was used to measure HR-QoL and includes 36 items that measure eight 
health domains: physical functioning, role limitations due to physical health problems, role 
limitations due to emotional problems, energy/fatigue, emotional well-being, social 
functioning, pain, and general health perceptions. An additional item assesses the change in 
health the last 12 month and is labelled health transition.  Each domain is scored on a scale 
from 0 to 100, with higher scores indicating better health outcomes 11.  
 
Data analysis 
In the quantitative analysis, descriptive statistics were used to summarize participant 
characteristics, background variables, recruitment, adherence, and satisfaction rates. 
Categorical data were reported as counts and percentages, while continuous variables were 
presented as means with standard deviations (SD) or medians with interquartile ranges, 
depending on the data distribution. To evaluate the limited efficacy of the intervention, Linear 
Mixed Models (LMM) were applied to data collected at baseline, 6 months, and 12 months. 
LMM was chosen for its ability to handle repeated measures and missing data, with time 
treated as both a fixed and repeated effect, an unstructured covariance type, and maximum 
likelihood estimation 12.  A paired sample t-test was conducted to analyze changes in physical 
activity between baseline and 12 months. In line with recommendations for feasibility studies 
by Bowen et al. (2009) 2, effect sizes were prioritized to assess limited efficacy and  P-values 
were reported for transparency but were not used to infer significance, as feasibility studies 
are not powered for hypothesis testing. For each outcome, we reported means, SDs, change 
scores with 95% confidence intervals (CI), p-values and effect sizes (Cohen’s d), interpreted 
using conventional thresholds where 0.20–0.49 indicates a small effect, 0.50–0.79 a 
moderate effect, and ≥0.80 a large effect. 
 
Limited efficacy was treated as an exploratory within group appraisal under Bowen’s 
framework. We summarised the pattern across domains rather than any single measure and 
flagged a limited efficacy signal when at least three target domains showed a Cohen’s d of 

0.20 or greater at 6 or 12 months. We considered durability to be supported when these 
changes were maintained or further improved at 12 months. These parameters describe 
feasibility stage signals and are not hypothesis tests or pass or fail rules.  All statistical 
analyses were performed using IBM SPSS version 25.0. 
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