Effectiveness of ergonomic interventions on work activity limitations in adults with rheumatoid arthritis: A systematic review

Abstract

BACKGROUND:

Rheumatoid arthritis (RA) is one of the leading causes of work disability in the United States. Ergonomic interventions offer an individualized treatment approach, and when used in conjunction with pharmacological treatment interventions, may improve work outcomes and improve the overall quality of life for individuals with RA.

OBJECTIVE:

To identify the current body of evidence regarding the effectiveness of ergonomic interventions in reducing work activity limitations in adults with RA.

METHODS:

A systematic review was conducted to identify articles of ergonomic interventions targeting working adults with RA. The CONsolidated Standards of Reporting Trials (CONSORT) checklist and Non-Pharmacological Treatment (NPT) Extension evaluated the reporting quality of each randomized controlled trial (RCT), and the Grading of Recommendation Assessment, Development, and Evaluation (GRADE) evaluated the quality of the evidence.

RESULTS:

Six studies were identified and reviewed for the quality of their reporting on evidence related to work activity limitations. Sixty-six percent of the items on the CONSORT checklist were fully reported by all studies and analysis through the GRADE framework demonstrated moderate confidence that the reported effects of ergonomic interventions on work activity limitations in the studies are accurate. This review revealed varied results for the effectiveness of ergonomic interventions on work activity limitations and at-work productivity.

CONCLUSION:

The results of this review indicate a need for further investigation. Future studies should focus on reviewing specific ergonomic interventions to determine the dosage needed to see results in reducing work activity limitations for working adults with RA.

Keywords

Rheumatology disability workplace

1 Background

Rheumatoid arthritis (RA) is one of the leading causes of work disability, a general term used to describe limitations in work activity or work participation, in the United States (US), affecting approximately 1.3 million adults [1 –3]. Individuals with RA are 53% less likely to be employed, and up to 50% of this population will stop working within ten years of diagnosis [2, 3]. However, prior to reaching work cessation, 44% of individuals with RA experience a period of reduced productivity in the workplace due to their health condition, making this an optimal time for intervention to avoid work loss [1]. Work activity limitations, potentially modifiable, reflect the inability to perform tasks needed for the job, where work participation restrictions reflect a reduction in the hours worked [2]. Work limitations, on an individual level, are characterized by decreased quality of life, empowerment, and participation. Additionally, RA symptom management is extremely costly, decreasing the earning potential on the individual level to ultimately result in economic instability, impacting society as a whole. The overall annual costs of RA, including direct costs, such as medical expenses, and indirect costs, including non-medical expenses, was estimated to be $52 billion as of 2019 [4]. Income loss due to work activity limitations has been estimated to be significantly higher than direct medical costs [5, 6]. This cost will increase as an individual’s at-work productivity decreases. Without the identification of interventions to address work activity limitations, individuals with RA will continue to face decreased quality of life and economic instability.

While pharmacological management is effective in symptom management of RA, pain, low adherence, adverse side effects, and high costs still influence reduced productivity levels, especially at work [6 –8]. Supplementary non-pharmacological interventions, such as ergonomic interventions, in conjunction with pharmacological treatments, could potentially improve work outcomes for people with RA.

Ergonomic interventions, an area of study focused on understanding and enhancing interactions that humans have with their environment [9] offer a tailored experience for patients, which may lead to improved work outcomes. Long-term outcomes are improved for musculoskeletal disorders when a tailored, supplementary non-pharmacological intervention is added to the treatment regimen. This was exhibited in one study, in which patient usage of pain medication decreased, and total working hours increased [8]. Additionally, a number of studies found that the addition of non-pharmacological interventions in the treatment of rheumatic and musculoskeletal conditions increased the overall quality of life and overall functioning of patients [10 –12]. Exploring the potential of adding non-pharmacological interventions, such as ergonomics, could be a promising, inexpensive intervention to improve the lives and work productivity of people with RA.

Certified ergonomists, such as occupational and physical therapists, can implement modifications to the work environment to decrease work activity limitations in adults with RA, including workstation setup and adjustment, schedule alteration, and the implementation of technology to assist with task completion [8, 10]. Previous research has focused on the use of ergonomic interventions in workers with low back pain, neck pain, and physical disabilities [13 –15]. In addition to a reduction in work activity limitations, study findings report improvements in overall quality of life related to their improved work environments [14]. The effectiveness of ergonomic interventions may vary depending on the mode of intervention, such as the addition of exercise plans in conjunction with workplace ergonomic interventions [15]. The collective results of the scientific evidence on the effectiveness of ergonomic interventions on improving productivity among workers with RA requires further investigation [10 –12]. A compilation of the current body of evidence on ergonomic interventions in the workplace for working adults with RA could potentially direct clinicians to prescribe an affordable treatment option which could address disability and socioeconomic consequences. Therefore, the objective of this study is to conduct a systematic review to synthesize and evaluate studies examining the effectiveness of ergonomic interventions on work activity for adults with RA.

2 Methods

2.1 Literature search

PubMed, CINAHL, and PsycINFO databases were searched to identify published literature examining ergonomic interventions aimed at reducing work activity limitations for people with RA from inception through June 1, 2020. MeSH headings were used to search PubMed, and subject headings were used to search CINAHL and PsycINFO. Search terms were grouped based on the construct of interest (work activity limitations OR “work disability” OR “activity limitations” OR “presenteeism”), target population (rheumatoid arthritis OR “RA” OR “rheumatology”), target setting (“workplace” OR “job” OR work^* OR “office”), and intervention type (ergonomics OR adaptations OR accommodations OR “human engineering”). See the Appendix for the complete search strategy. Hand searching, reviewing the reference lists of related studies, was utilized to supplement the number of studies that were indexed in the included databases [16].

Articles identified were evaluated using the following inclusion and exclusion criteria: 1) study design: randomized clinical trials (RCTs), 2) study participants: adults 18 years or older, employed part-time or full-time, working at least five hours per week, as this is the average number of hours that an employee needs to work for a mandated break by the U.S. Department of Labor [17], 3) diagnosis: RA, 4) intervention: ergonomic intervention, defined by the International Ergonomics Association as the procedures, content, and equipment and tools used to perform tasks, as well as the types of jobs, technology, and work roles used [9], and 5) language: articles published in English. Studies were excluded if: 1) study participants were out of work for more than six months, and 2) study participants were receiving treatments for additional diagnoses during the time of the trial.

2.2 Data extraction

Study titles from the search were organized using a citation manager, Zotero, and duplicates from database searches were removed. One reviewer screened the titles for relevance. Abstracts and the full text of articles were screened independently by two reviewers for inclusion in the review. Disagreements were resolved by a third author when needed. The reviewers extracted the following from included articles: year of the trial, number of participants, mean age of participants, participant diagnosis, intervention/control, and outcome: value of work activity limitations.

2.3 Quality assessment of reporting

Following data extraction, the studies were evaluated using the CONsolidated Standards of Reporting Trials (CONSORT) and Non-Pharmacological Treatments (NPT) Extension. The CONSORT statement provides authors with a minimum set of standards required to ensure transparency in reporting RCTs to reduce the impact of bias on the reporting of trial findings [18]. The NPT Extension was developed specifically to address reporting difficulties for trials utilizing non-pharmacological interventions, such as surgery, rehabilitation, and psychotherapy [19]. Items on the CONSORT checklist were scored as “fully reported”, “partially reported”, “not reported”, “not reported but unable to determine if relevant/done”, or “not relevant”. For an article to receive a designation as “fully reported”, all requirements of the CONSORT item must be reported, whereas a “partially reported” item contains some but not all of the requirements. If the CONSORT item was relevant and should be reported, but was not, the item was designated as “not reported”. However, if the CONSORT requirements were not reported but it was unclear if it was relevant, it may be “not reported but unable to determine if relevant or done”. If the CONSORT item did not apply to the RCT, it was deemed “not relevant” for reporting [20]. Two reviewers independently evaluated all of the studies for their reporting quality, with potential disagreements resolved by a third author.

2.4 Quality assessment of content

Two reviewers evaluated the quality of evidence for the outcome of interest using the GRADE framework. The GRADE framework allows reviewers to comprehensively and transparently assess the collective quality of study outcomes, as well as the strength of study recommendations for use in healthcare practice [21]. The results of GRADE are based upon the evidence presented across studies for one outcome of interest, and a rating is assigned to the cumulative evidence supporting a singular outcome of interest. GRADE categorizes and summarizes the evidence related to a single outcome across studies into four levels: high, moderate, low, and very low, to reflect confidence that the effect estimates are correct [22]. RCTs, such as the studies included in this review, begin as high-level evidence and can be upgraded or downgraded based on eight areas. Both reviewers independently assessed five areas within GRADE, including risk of bias, indirectness, imprecision, inconsistency, or publication bias to determine if there was a serious risk. Each area was scored 0 if there was no risk, –1 if there was a serious risk, or –2 if there was a very serious risk. Additionally, three areas were evaluated to see if there was an increase in the quality of the content, including large effect, dose response, and plausible residual confounding. Large effect could be score 0, +1 if there was a large effect, or +2 if there was a very large effect, dose response could be scored 0 or +1 if there was evidence of a gradient, and plausible residual confounding could be scored 0 or +1 if it would reduce a demonstrated effect.

3 Results

Three hundred and eleven studies were identified: 129 from PubMed, 130 from CINAHL, and 52 from PsycInfo. Following the removal of duplicates, 245 studies remained. Following the title screen, 59 studies remained of the 245 screened. The abstracts of those 59 were screened, and seven articles remained. The full text of seven articles were reviewed, and two were excluded. Hand searching was used to supplement the results, and one article was identified. In total, six studies were included in the final review. See Fig. 1 for complete details. The included studies were conducted in the United States, England, and the Netherlands. The sample sizes ranged from 55 to 287 participants and included participants with RA, as well as other diagnoses, such as osteoarthritis, back pain, and other forms of inflammatory arthritis. The studies assessed the effectiveness of various ergonomic interventions on participants’ work activity. Further details of the included studies can be found in Table 1.

Fig. 1

PRISMA flow diagram.

Table 1

Characteristics of studies

Author, year	Participants n = Age †	Diagnosis	Treatments	Outcome (measure)	Results
Allaire, 2003‡	n = 242, I: 122 C: 120 Age: 49.5 years (24–66)	RA, knee OA, systemic lupus erythematosus, ankylosing spondylitis, or PA	Intervention: Job accommodation, vocational counseling and guidance, and education and self-advocacy Control: Pamphlets and flyers regarding how to manage health-related employment problems and available resources	Time to permanent job loss or temporary job loss (participant report)	Job loss delay and reduction
Baldwin, 2012‡	n = 89 I: 48 C: 41 Age: 50.4 years (18–61)	RA or OA	Intervention: Individual workplace assessments, with a resulting work plan to improve arthritis-related vocational difficulties Control: Written educational materials	Impact of arthritis on work performance (AIMS2)	Decreased arthritis- related workplace difficulties
Hammond, 2017‡	n = 55 I: 29 C: 26 Age: 49 years	RA, PA, or undifferentiated IA	Intervention: Written self-help work information, structured work interview and job discussion, and work barriers, action planning, and individualized VR program, including self-management, job accommodations, employment rights information, and other strategies Control: Written self-help work information	Presenteeism (RA-WIS, WALS, WLQ)	Improved job loss and improved productivity
Keysor, 2018‡	n = 287 I: 143 C: 144 Age: 50.4 years (21–65)	OA, RA, back pain, fibromyalgia, PA, systemic lupus, ankylosing spondylitis, systemic sclerosis	Intervention: WES-RC assessment and solution suggestion, written resource material for employment retention organizations, local vocational rehab programs, local disability advocacy centers, voluntary health agencies, voluntary health agencies, and chronic disease management Control: Written resource material for employment retention organizations, local vocational rehab programs, local disability advocacy centers, voluntary health agencies, voluntary health agencies, and chronic disease management	Work limitation (WLQ)	No impact on work limitations, but did find reduction in work loss
van Vilsteren, 2017‡	n = 150 I: 75 C: 75 Age: 49.7 years (18–64)	RA	Intervention: Usual rheumatologist-led care, integrated care, participatory workplace intervention Control: Usual rheumatologist-led care	Work productivity (WLQ)	No intervention effects
Vilsteren, 2017‡	150 I: 75 C: 75 Age: 49.7 years (18–64)	RA	Intervention: Usual rheumatologist-led care, integrated care, participatory workplace intervention Control: Usual rheumatologist-led care	At-work productivity loss (WLQ)	No intervention effects

†age value is mean age (age range); the study by Hammond did not include an age range for participants. ‡study design is a randomized controlled trial (RCT). ^*RA = rheumatoid arthritis; OA = osteoarthritis; PA = psoriatic arthritis; IA = inflammatory arthritis; WLQ = Work Limitations Questionnaire; RA-WIS = Work Instability Scale for Rheumatoid Arthritis; WALS = Workplace Activity Limitations Scale AIMS2 = Arthritis Impact Measure Scale.

3.1 Quality assessment of reporting

The average number of items on the CONSORT checklist designated as “fully reported” for all of the studies was 29 out of 44 items. For example, item 2b “specific objectives of hypotheses” in the introduction section was fully reported by all six studies, as each study explicitly stated their objective. The full reporting quality of reporting results are summarized in Table 2.

Table 2
CONSORT checklist with NPT items

CONSORT item NPT item Fully reported Partially reported Not reported Not reported, but unable to determine if relevant or done Not relevant

Title and abstract

1a: Identification as a randomized trial in the title 5 0 1 0 0

1b: Structured summary of trial design, methods, results, and conclusions (for specific guidance see CONSORT for abstracts) 0 6 0 0 0

Introduction

2a: Scientific background and explanation of rationale 6 0 0 0 0

2b: Specific objectives or hypotheses 6 0 0 0 0

Methods

3a: Description of trial design (such as parallel, factorial) including allocation ratio When applicable, how care providers were allocated to each trial group 2 2 2 0 0

3b: Important changes to methods after trial commencement (such as eligibility criteria), with reasons 3 0 0 2 1

4a: Eligibility criteria for participants When applicable, eligibility criteria for centers and for care providers 6 0 0 0 0

4b: Settings and locations where the data were collected 3 3 0 0 0

5: The interventions for each group with sufficient details to allow replication, including how and when they were actually administered Precise details of both the experimental treatment and comparator 5 1 0 0 0

5a Description of the different components of the interventions and, when applicable, description of the procedure for tailoring the interventions to individual participants. 6 0 0 0 0

5b Details of whether and how the interventions were standardized. 1 1 2 2 0

5c Details of whether and how adherence of care providers to the protocol was assessed or enhanced 2 0 2 2 0

5d Details of whether and how adherence of participants to interventions was assessed or enhanced 1 1 4 0 0

6a: Completely defined pre-specified primary and secondary outcome measures, including how and when they were assessed 5 1 0 0 0

6b: Any changes to trial outcomes after the trial commenced, with reasons 0 0 0 4 2

7a: How sample size was determined When applicable, details of whether and how the clustering by care providers or centers was addressed 3 2 0 1 0

7b: When applicable, explanation of any interim analyses and stopping guidelines 1 0 0 1 4

8a: Method used to generate the random allocation sequence 6 0 0 0 0

8b: Type of randomization; details of any restriction (such as blocking and block size) 6 0 0 0 0

9: Mechanism used to implement the random allocation sequence (such as sequentially numbered containers), describing any steps taken to conceal the sequence until interventions were assigned 6 0 0 0 0

10: Who generated the random allocation sequence, who enrolled participants, and who assigned participants to interventions 5 0 1 0 0

11a: If done, who was blinded after assignment to interventions (for example, participants, care providers, those assessing outcomes) and how If done, who was blinded after assignment to interventions (e.g., participants, care providers, those administering co-interventions, those assessing outcomes) and how 2 0 3 0 1

11b: If relevant, description of the similarity of interventions 5 0 0 1 0

11c If blinding was not possible, description of any attempts to limit bias 3 0 3 0 0

12a: Statistical methods used to compare groups for primary and secondary outcomes When applicable, details of whether and how the clustering by care providers or centers was addressed 6 0 0 0 0

12b: Methods for additional analyses, such as subgroup analyses and adjusted analyses 3 1 1 1 0

Results

13a: For each group, the numbers of participants who were randomly assigned, received intended treatment, and were analyzed for the primary outcome The number of care providers or centers performing the intervention in each group and the number of patients treated by each care provider or in each center 6 0 0 0 0

13b: For each group, losses and exclusions after randomization, together with reasons 6 0 0 0 0

13c For each group, the delay between randomization and the initiation of the intervention 2 0 4 0 0

new Details of the experimental treatment and comparator as they were implemented 6 0 0 0 0

14a: Dates defining the periods of recruitment and follow-up 3 1 2 0 0

14b: Why the trial ended or was stopped 1 0 0 0 5

15: A table showing baseline demographic and clinical characteristics for each group When applicable, a description of care providers (case volume, qualification, expertise, etc.) and centers (volume) in each group. 6 0 0 0 0

16: For each group, number of participants (denominator included in each analysis and whether the analysis was by original assigned groups 4 2 0 0 0

17a: For each primary and secondary outcome, results for each group, and the estimated effect size and its precision (such as 95% confidence interval) 6 0 0 0 0

17b: For binary outcomes, presentation of both absolute and relative effect sizes is recommended 1 1 1 2 1

18: Results of any other analyses performed, including subgroup analyses and adjusted analyses, distinguishing pre-specified from exploratory 3 1 0 1 1

19: All important harms or unintended effects in each group (for specific guidance see CONSORT for harms) 1 0 0 4 1

Discussion

20: Trial limitations, addressing sources of potential bias, imprecision, and, if relevant, multiplicity of analyses In addition, take into account the choice of the comparator, lack of or partial blinding, and unequal expertise of care providers or centers in each group 5 0 0 1 0

21: Generalizability (external validity, applicability) of the trial findings Generalizability (external validity) of the trial findings according to the intervention, comparators, patients, and care providers and centers involved in the trial 4 2 0 0 0

22: Interpretation consistent with results, balancing benefits and harms, and considering other relevant evidence 6 0 0 0 0

Other information

23: Registration number and name of trial registry 4 0 1 1 0

24: Where the full trial protocol can be accessed, if available 4 0 0 2 0

25: Sources of funding and other support (such as supply of drugs), role of funders 6 0 0 0 0

CONSORT item	NPT item	Fully reported	Partially reported	Not reported	Not reported, but unable to determine if relevant or done	Not relevant
Title and abstract
1a: Identification as a randomized trial in the title		5	0	1	0	0
1b: Structured summary of trial design, methods, results, and conclusions (for specific guidance see CONSORT for abstracts)		0	6	0	0	0
Introduction
2a: Scientific background and explanation of rationale		6	0	0	0	0
2b: Specific objectives or hypotheses		6	0	0	0	0
Methods
3a: Description of trial design (such as parallel, factorial) including allocation ratio	When applicable, how care providers were allocated to each trial group	2	2	2	0	0
3b: Important changes to methods after trial commencement (such as eligibility criteria), with reasons		3	0	0	2	1
4a: Eligibility criteria for participants	When applicable, eligibility criteria for centers and for care providers	6	0	0	0	0
4b: Settings and locations where the data were collected		3	3	0	0	0
5: The interventions for each group with sufficient details to allow replication, including how and when they were actually administered	Precise details of both the experimental treatment and comparator	5	1	0	0	0
5a	Description of the different components of the interventions and, when applicable, description of the procedure for tailoring the interventions to individual participants.	6	0	0	0	0
5b	Details of whether and how the interventions were standardized.	1	1	2	2	0
5c	Details of whether and how adherence of care providers to the protocol was assessed or enhanced	2	0	2	2	0
5d	Details of whether and how adherence of participants to interventions was assessed or enhanced	1	1	4	0	0
6a: Completely defined pre-specified primary and secondary outcome measures, including how and when they were assessed		5	1	0	0	0
6b: Any changes to trial outcomes after the trial commenced, with reasons		0	0	0	4	2
7a: How sample size was determined	When applicable, details of whether and how the clustering by care providers or centers was addressed	3	2	0	1	0
7b: When applicable, explanation of any interim analyses and stopping guidelines		1	0	0	1	4
8a: Method used to generate the random allocation sequence		6	0	0	0	0
8b: Type of randomization; details of any restriction (such as blocking and block size)		6	0	0	0	0
9: Mechanism used to implement the random allocation sequence (such as sequentially numbered containers), describing any steps taken to conceal the sequence until interventions were assigned		6	0	0	0	0
10: Who generated the random allocation sequence, who enrolled participants, and who assigned participants to interventions		5	0	1	0	0
11a: If done, who was blinded after assignment to interventions (for example, participants, care providers, those assessing outcomes) and how	If done, who was blinded after assignment to interventions (e.g., participants, care providers, those administering co-interventions, those assessing outcomes) and how	2	0	3	0	1
11b: If relevant, description of the similarity of interventions		5	0	0	1	0
11c	If blinding was not possible, description of any attempts to limit bias	3	0	3	0	0
12a: Statistical methods used to compare groups for primary and secondary outcomes	When applicable, details of whether and how the clustering by care providers or centers was addressed	6	0	0	0	0
12b: Methods for additional analyses, such as subgroup analyses and adjusted analyses		3	1	1	1	0
Results
13a: For each group, the numbers of participants who were randomly assigned, received intended treatment, and were analyzed for the primary outcome	The number of care providers or centers performing the intervention in each group and the number of patients treated by each care provider or in each center	6	0	0	0	0
13b: For each group, losses and exclusions after randomization, together with reasons		6	0	0	0	0
13c	For each group, the delay between randomization and the initiation of the intervention	2	0	4	0	0
new	Details of the experimental treatment and comparator as they were implemented	6	0	0	0	0
14a: Dates defining the periods of recruitment and follow-up		3	1	2	0	0
14b: Why the trial ended or was stopped		1	0	0	0	5
15: A table showing baseline demographic and clinical characteristics for each group	When applicable, a description of care providers (case volume, qualification, expertise, etc.) and centers (volume) in each group.	6	0	0	0	0
16: For each group, number of participants (denominator included in each analysis and whether the analysis was by original assigned groups		4	2	0	0	0
17a: For each primary and secondary outcome, results for each group, and the estimated effect size and its precision (such as 95% confidence interval)		6	0	0	0	0
17b: For binary outcomes, presentation of both absolute and relative effect sizes is recommended		1	1	1	2	1
18: Results of any other analyses performed, including subgroup analyses and adjusted analyses, distinguishing pre-specified from exploratory		3	1	0	1	1
19: All important harms or unintended effects in each group (for specific guidance see CONSORT for harms)		1	0	0	4	1
Discussion
20: Trial limitations, addressing sources of potential bias, imprecision, and, if relevant, multiplicity of analyses	In addition, take into account the choice of the comparator, lack of or partial blinding, and unequal expertise of care providers or centers in each group	5	0	0	1	0
21: Generalizability (external validity, applicability) of the trial findings	Generalizability (external validity) of the trial findings according to the intervention, comparators, patients, and care providers and centers involved in the trial	4	2	0	0	0
22: Interpretation consistent with results, balancing benefits and harms, and considering other relevant evidence		6	0	0	0	0
Other information
23: Registration number and name of trial registry		4	0	1	1	0
24: Where the full trial protocol can be accessed, if available		4	0	0	2	0
25: Sources of funding and other support (such as supply of drugs), role of funders		6	0	0	0	0

^*CONSORT = CONsolidated Standards of Reporting Trials; NPT = Non-Pharmacological Extension.

Five of the six studies provided details on the interventions for both groups and the components to allow for replication of the trial. However, only one of the trials documented the adherence and standardization procedures. A key component of RCTs is the standardization of the procedures used during the trial in order to determine intervention effects. A lack of reporting of these procedures by authors may imply that these steps were not conducted and may lead to decreased confidence in the quality of the trial and the results.

Only two of the six studies fully reported blinding procedures during the interventions. It is common in rehabilitation-based trials to be limited in the ability to blind all parties to the interventions. However, only three of the six studies reported attempts to limit bias when blinding was not possible. Despite difficulty in blinding during non-pharmacological interventions, authors should document who was able to be blinded, as well as their attempt to limit bias within the study when blinding did not occur.

Additionally, only one of the six included studies reported harms or unintended effects within their study. Providing this information gives readers the ability to weigh the benefits and risks of the trial. Even if no unintended effects or harms occurred within the trial, in order to provide readers with the most accurate information, it should be explicitly stated if there were or were not harms or unintended effects.

Surprisingly, one of the six studies did not identify itself as an RCT in the title. While all of the studies provided a structured abstract, all six abstracts were labeled as “partially reported” due to missing information according to CONSORT for abstracts [23]. Complete and accurate reporting of bias increases the internal and external validity of study results [24]. A lack of reporting within the RCT does not mean that the trial was incomplete, however it may decrease the confidence of the study findings.

3.2 Quality assessment of content

The body of evidence, including the six studies related to the effectiveness of ergonomic interventions in reducing work activity limitations for working adults with RA, was collectively examined and assigned a rating of moderate based on an analysis using the GRADE framework. A detailed summary of the definitions for each level and possible score for each section is provided in Table 3. All of the studies were RCTs and began as high-quality evidence. Risk of bias assessed the limitations related to the study design, and specifically examined the impact of the following factors on the estimate of the treatment effect: lack of allocation concealment, lack of blinding, incomplete accounting of patient and outcome events, selective outcome reporting, or other limitations such as stopping the trial early. The studies included in this review did not suffer from major limitations due to biased assessment of intervention effects, and was subsequently scored 0, indicating no serious risk. Inconsistency examined the unexplained differences in the estimated effects between studies. The studies reported varying results and effect estimates of the ergonomic interventions on work activity limitations and was subsequently scored –1 for a serious risk. Indirectness referred to a lack of direct research studies with the interventions of interest, in populations of interest. All of the included studies incorporated ergonomic interventions in working adults with RA, and this section was scored 0, indicating no serious risk. Imprecision referred to studies including a low number of participants and events, resulting in a wide confidence interval. This was judged not to be a serious risk and was scored 0. Publication bias occurs when there was an under- or over-estimation of the effect due to discerning publication of studies. This was also judged not to be a serious risk and was scored 0.

Table 3
GRADE framework and scoring guide

Study design Lower if Higher if Quality of a body of evidence: Level + Definition

Randomized trials: High Risk of bias –1 serious –2 very serious Large effect +1 large +2 very large High (++++) “We are confident that the true effect lies close the that of the estimate of the effect” [21 p. 404].

Inconsistency –1 serious –2 very serious Dose response +1 evidence of a gradient Moderate (+++) “We are moderately confident in the effect estimate. The true effect is likely to be close to the estimation of the effect, but there is a possibility that is substantially different” [21 p. 404].

Observation studies: Low Indirectness –1 serious –2 very serious All plausible residual confounding +1 would reduce a demonstrated effect Low (++) “Our confidence in the effect estimate is limited: The true effect may be substantially different from the estimate of the effect” [21 p. 404].

Imprecision –1 serious –2 very serious Very Low (+) “We have very little confidence in the effect estimate: The true effect is likely to be substantially different from the estimate of effect” [21 p. 404].

Publication bias –1 likely –2 very likely

Study design	Lower if	Higher if	Quality of a body of evidence: Level + Definition
Randomized trials: High	Risk of bias –1 serious –2 very serious	Large effect +1 large +2 very large	High (++++) “We are confident that the true effect lies close the that of the estimate of the effect” [21 p. 404].
	Inconsistency –1 serious –2 very serious	Dose response +1 evidence of a gradient	Moderate (+++) “We are moderately confident in the effect estimate. The true effect is likely to be close to the estimation of the effect, but there is a possibility that is substantially different” [21 p. 404].
Observation studies: Low	Indirectness –1 serious –2 very serious	All plausible residual confounding +1 would reduce a demonstrated effect	Low (++) “Our confidence in the effect estimate is limited: The true effect may be substantially different from the estimate of the effect” [21 p. 404].
	Imprecision –1 serious –2 very serious		Very Low (+) “We have very little confidence in the effect estimate: The true effect is likely to be substantially different from the estimate of effect” [21 p. 404].
	Publication bias –1 likely –2 very likely

^*GRADE = Grading of Recommendations Assessment, Development, and Evaluation.

According to GRADE, the evidence may be upgraded due to a large or very large effect; however, this was scored 0 as it was not applicable. Additionally, the evidence may be upgraded due to the presence of a dose response gradient. This was not present in the included studies and was scored 0. Plausible residual confounding was also not present, as it was only appropriate for upgrading the evidence from observational studies and was scored 0. Based upon the results above, the evidence was scored moderate, as it was only downgraded one for inconsistency, resulting in a score of three overall. This means that there was moderate confidence in the estimated effect, with the potential for that effect to be different. The results of the assessment of evidence are reported in Table 4.

Table 4

GRADE evaluation of evidence

	At-work productivity loss/work limitations	Rating
Studies, n=	6
Design	0 (starting at 4)	++++
Limitations (risk of bias)	0	++++
Indirectness	0	++++
Inconsistency	–1	+++
Imprecision	0	+++
Publication bias	0	+++
Large effect +1 or +2 or 0	0	+++
Dose response +1 or 0	0	+++
Plausible residual Confounding +1 or 0	0	+++
Quality		+++Moderate

^*GRADE = Grading of Recommendations Assessment, Development, and Evaluation.

The current body of evidence supporting the implementation of ergonomic interventions for working adults with RA demonstrated inconsistency in the estimated effects of ergonomic interventions. Due to varying results and effect estimates of the ergonomic interventions on work activity limitations the evidence was scored –1 for a serious risk. Four of the six studies found that ergonomic interventions demonstrated success in preventing or delaying job loss, improving at-work productivity, and decreasing arthritis related work difficulties [25 –28]. Specifically, one of the six studies reported improvements in both job loss and productivity [27], with another study identifying improvements in work activity limitations related to arthritis [26]. Two of the six studies found no impact on at-work productivity from the ergonomic interventions used in the trials, but did identify improvements in job loss only [25, 28]. Two studies found no effect on any form of work disability [29, 30].

4 Discussion

This is the first systematic review to examine ergonomic interventions and their impact on work activity limitations in adults with RA. This study revealed varied results for the effectiveness of ergonomic interventions on work activity limitations, which may be due to the heterogeneity of the ergonomic interventions implemented across the six studies. The results across studies suggest that ergonomic interventions may decrease work disability, including work activity limitations, as well as work participation. However, with only two of the six studies specifically reporting improvements in work activity limitations, more research is needed to provide support for the use of ergonomic interventions in reducing work activity limitations for adults with RA.

An increase in studies examining ergonomic interventions may increase the consistency, as studies may be grouped based on the specific intervention variables used (i.e., workstation set-up versus schedule modifications). For example, the studies included in this review primarily focused on the following ergonomic interventions: education on workplace rights and resources, identification and evaluation of workplace barriers currently impacting work performance and potential solutions to those barriers, and physical changes to the work environment. However, studies evaluating the effectiveness of ergonomic interventions in other populations also utilized ergonomic interventions related to education and evaluation of and adaptations to the workplace. Additionally, the studies looking at other populations also included exercise and postural adaptations in addition to the above interventions.

One intervention included in all six studies was the identification of workplace barriers and their solutions [25 –30]. However, only three studies focused on making physical changes to the work environment [25 –27] and only four studies incorporated educational material for participants [25 –28]. The two studies that noted no impact on at-work productivity primarily focused on the identification of workplace barriers and solutions, with a decreased emphasis on education and the implementation of physical changes when compared with the other trials [29, 30]. Interestingly, the study by Allaire et al. included aspects of all of the above-mentioned ergonomic interventions, yet only found improvements in job loss but not at-work productivity [25], whereas the study by Keysor et al. mainly focused on education and identification of barriers, but had the a similar conclusion [28]. The discrepancies in results made it difficult to draw meaningful conclusions on the effects of ergonomic interventions in reducing work activity limitations in adults with RA. One way to address this in future studies would be to focus on the identification of specific ergonomic interventions that reduce work activity limitations to draw more meaningful conclusions.

The evaluation of the reporting quality of the studies via the CONSORT guidelines revealed suboptimal reporting within the areas related to harms and effects, adherence and standardization, and blinding to the interventions. It is vital that authors are transparent in the reporting of their trials in order to have accurate interpretation of the results and effectiveness. First, transparency regarding any potential harms or negative effects of an intervention during a trial is essential. Even if there were no harms noted during the trial, it is important to report this in order to provide all relevant information to readers. Next, the reporting of the standardization and adherence of participants and providers to the interventions should increase confidence that the trial was carried out as intended and reduces the chance of a result occurring due to another factor. Without standardizations and procedures put in place, the possibility that the results of the intervention being due to something besides the intervention increases. Finally, blinding within an RCT is key to reducing the bias within the study. There is significant difficulty in blinding participants and care providers for non-pharmacological treatment interventions, however even when blinding is not possible, any attempts to blind and/or limit bias should be reported, such as blinding of data collectors. Overall, the reporting of all aspects of a study, according to the CONSORT guidelines, is vital to ensure that the results are reliable and valid to determine the effectiveness of the reported results of ergonomic interventions on working adults with RA.

The evaluation using the GRADE framework revealed moderate confidence in the evidence, due to inconsistency. Consistent effects across studies increases the confidence that the true effect of the intervention is close to what is reported. When studies report inconsistent results, such as the RCTs included in this review, the confidence in that effect decreases. Ergonomics is a broad term that may be used to describe a wide variety of interventions, and the inconsistency among effect sizes for the included studies may be due to a variability in the specific ergonomic area examined.

To supplement the existing body of evidence, future research should focus on the effects of ergonomic interventions when used in conjunction with medication as a multifaceted treatment approach. Specifically, healthcare professionals, such as physical and occupational therapists, would benefit from research focused on the dosages needed of non-pharmacological treatments, such as ergonomic interventions, to work effectively in conjunction with pharmacological treatments to decrease work activity limitations in adults with RA. Additionally, health professionals would benefit from further research into the effects of specific ergonomic interventions on work activity limitations for adults with RA, in order to provide the most appropriate evidence-based treatment.

5 Limitations

This study is not without limitations. Through the exclusion of studies published in a language other than English, the chance of bias is introduced. Also, while the aim was to use inclusive search terms, there is a possibility of missing studies due to the search terms used. The included studies focused on participants with multiple diagnoses including low back pain, and other rheumatic conditions, which could impact the results of the RCTs, and subsequently this review. Due to COVID-19 and resulting campus closures, the number of databases searched was reduced from four to three, which may have resulted in studies remaining unidentified.

6 Conclusions

More evidence is needed to confirm the full impact of ergonomic interventions on reducing work activity limitations for working adults with RA. Based on the results of the six studies included in this review, ergonomic interventions appear to be effective in reducing some aspects of work disability, but the results are varied when it comes to work activity limitations specifically. Individuals experiencing work activity limitations face decreased participation in their preferred occupations. Future studies should focus on reviewing specific ergonomic interventions in order to determine the dosage needed to see results in reducing work activity limitations for working adults with RA.

Footnotes

Acknowledgments

The authors thank Jessica Bell, Director of Library and Instructional Design, for her assistance in developing the search strategy for this systematic review.

Conflict of interest

The authors have no conflicts of interest to report.

Supplementary materials

The appendices are available from .

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