Study design

A cross-sectional, nationwide survey study was conducted in people with RA or axSpA. Ethical approval to conduct the study was obtained from the Medical Ethics Committee Leiden The Hague Delft (W.23.007). This study was conducted in agreement with the declaration of Helsinki [15] and in compliance with the General Data Protection Regulations and the Dutch Medical Research Involving Human Subjects Act. All participants provided informed consent for their participation. As recommended by the Enhancing the QUAlity and Transparency Of health Research (EQUATOR) network, this study is reported in line with the Checklist for Reporting Results of Internet E-Surveys (CHERRIES) [16] and the STrengthening the Reporting of OBservational studies in Epidemiology (STROBE) checklist [17] (see Appendix 2 for the filled checklists).

Participants

People were eligible for participation in the study if they were aged ≥ 16 years and reported a physician-confirmed diagnosis of RA or axSpA. Our rationale for this age limit is that education in the Netherlands is compulsory until the age of 16 [18]. After this age, people can enter the labour market. Furthermore, axSpA typically affects people from a young age [19]. People with a paid job (currently or in the past) could participate in the study. Participants were recruited via a link to the survey on the websites and social media channels of the Dutch Arthritis Society (ReumaNederland), the Dutch axial SpA foundation (Stichting axiale SpA Nederland), the Dutch foundation for adolescents with rheumatic diseases (Youth-R-Well), an online journal for people with rheumatic diseases (ReumaMagazine) and on nine Facebook groups for people with RA or axSpA. The survey was disseminated between May 19th and September 4th, 2023. Because of the descriptive character of this study, a sample size calculation was considered not applicable. We used a convenience sampling method and roughly aimed for a minimum of 800 respondents, as we considered this as necessary to reach sufficient numbers of participants within each category of work status and disease.

Study context

In the Netherlands, rheumatologists and other HCPs, such as general practitioners and physiotherapists, share the responsibility of identifying work-related problems in people with RA or axSpA to facilitate timely work-related support [11, 20, 21]. In the Netherlands, occupational HCPs, including occupational physicians and labour experts, can provide work-related support for employees. According to the Dutch Eligibility for Permanent Incapacity Benefit (restrictions) Act, employers are obliged to offer their employees on prolonged sick leave (i.e., ≥ 6 weeks) a consultation with an occupational physician [22,23,24]. Moreover, employees can approach an occupational HCP themselves in case they want work-related support as a preventive measure in the event of work-related problems or short- term sick leave [22]. Self-employed people have no occupational physician and are only advised to have a sick leave and/or disability insurance [25].

Self-employed people with a sick leave and/or disability insurance are entitled to comparable work-related support as employed people. As a consequence of being uninsured, self-employed people may have no income during their sick leave or in case of job loss.

Survey

The survey (see Appendix 1) consisted of 43 items, of which 10 items (i.e., items on education level, comorbidities, employment type, job sector, size of company and working hours) were based on existing, validated items from the Dutch Central Bureau of Statistics (CBS) [26, 27] and two items (i.e., items on work ability and health-related quality of life) were validated outcome measures [28, 29]. The other 31 items were generated by the authors based on previous qualitative studies regarding work-related support for people with RA or axSpA [12,13,14, 24, 30]. In the pre-testing phase, the survey was presented to the research team (four researchers with experience in qualitative and quantitative research) in order to provide input and recommendations on the wording, clarity, and comprehension of the items. Twenty laypersons from the general population then completed the survey to assess how items were interpreted by the target population (e.g. face validity [31]). Items that laypersons found unclear were reformulated or removed from the survey after consultation with the research group.

The survey focused on experiences of (self-)employed participants with work-related problems concerning work-related support from HCPs and employers. Furthermore, items on the participants’ sociodemographic and health characteristics, work characteristics and work-related problems were included. The sociodemographic and health characteristics were collected from all participants, while the work characteristics and work-related problems were only gathered from current (self-)employed participants. All (self-)employed participants with work-related problems filled in the items about experiences with the rheumatologist and other HCPs. Employed participants also completed items about their experiences with their employer. The survey was administered via an online link using the OnlinePROMs® software (2020; Interactive Studios, conform ISO27001 and NEN7510). The completion of the survey took approximately 15 min to finish, and the results could not be linked to an IP address.

Sociodemographic and health characteristics

Sociodemographic characteristics included age, sex, educational level, including low, medium and high [26], and whether participants (partly) stopped working due to the disease (yes/no). The health characteristics included self-reported diagnosis of RA or axSpA, self-reported disease duration and the number of comorbidities in the past 12 months, including diabetes, cardiovascular diseases, pulmonary diseases, cancer, migraine or severe headache, gastrointestinal complaints, musculoskeletal pain not related to RA/axSpA, allergy, urinary incontinence, liver diseases, kidney diseases, depression, obesity, Parkinson’s disease, and multiple sclerosis [26]. To assess the overall health-related quality of life (HRQoL) of participants, the validated Dutch translated EuroQol- 5 Dimensions 5-Level (EQ-5D-5L) was administered [28, 32]. The EQ-5D-5L comprises five items covering the dimensions mobility, self-care, activities of daily living, pain/discomfort and anxiety/depression. The Dutch health utility score ranges from − 0.446 to 1.000, with a score of 1 defining full health and a score below zero representing a health state worse than death [28, 32, 33]. In addition, participants completed the EQ-visual analogue scale (VAS) on their current health status, ranging from 0 (worst) to 100 (best).

Work characteristics and work-related problems

Items on work characteristics included employment type (employed/self-employed), job sector, including agricultural, craftmanship, transport, administrative, commercial, service and other size of company (categories of number of employees) and working hours (categories in hours/week), and were based on similar items used in national surveys [27]. Occupational class was determined according to the International Standard Classification of Occupations 2008 (ISCO-08) [34].The classification considers nine major occupational classes, which were further categorized, based on a previous study [35], into two categories: white-collar workers (i.e. managers, teachers, service and sales workers) and blue-collar workers (i.e. agricultural, forestry and fishery workers, cleaners).

Items on work-related problems included existence of work-related problems due to RA or axSpA in the past 12 months (yes/no) and if present, their type, including fatigue, pain in joints/muscles, stiffness of joints/muscles, morning or starting stiffness, difficulty moving and swollen joints, presence of current sick leave due to RA or axSpA (yes/no) and duration of current sick leave (categories in months). The self-reported work ability ofparticipants was assessed with the Work Ability Index-Single Item Scale (WAS) [29, 36]. The WAS is a responsive outcome measure to assess the status and progress of work ability and is highly predictive for future sick leave. It consists of a numeric rating scale (NRS) indicating the level of work ability an individual experiences at the moment of measuring ranging from 0 = completely unable to work at all, to 10 = work ability at its best, and distinguishing the following well-accepted categories: 0–5 = poor, 6–7 = moderate, 8–9 = good, and 10 = excellent work ability [29].

Experiences with work-related support from rheumatologists, other HCPs and employers

The items on experiences of participants in the past 12 months were distinguished by three groups: experiences with discussing work-related problems with (1) a rheumatologist or specialized rheumatology nurse, (2) other HCP(s),such as physiotherapists, general practitioners, occupational physicians, and (3) the employer (not applicable for self-employed participants). The items comprised for each group: discussed work-related problems in the past 12 months (yes/no), if not: reasons for not discussing work-related problems and if yes: advices or actions arisen from discussing problems. Additionally, in group 1 (rheumatologist or specialized rheumatology nurse), a question about whether the participant had a rheumatology consultation in the past 12 months was included. Furthermore, in group 2 (other HCPs), participants were asked if the advices or actions they received from the HCP were sufficient (yes/no).

Analysis

Descriptive statistics were used to analyze the data of the total sample, and separately for the employed, self-employed and not employed participants and RA and axSpA populations. Normally distributed continuous variables were presented as means with standard deviations (SD) and variables with a skewed distribution as medians with interquartile ranges (IQR). Categorical variables were shown as frequencies with percentages. All statistical analyses were performed with IBM SPSS Statistics for Windows, version 29.0 (IBM Corp, Armonk, NY, USA).