The study was conducted in the outpatient clinic of the Department of Physical Medicine and Rehabilitation in Satasairaala, Finland. The rehabilitation evaluation process at the unit specializes in comprehensive evaluation, with an emphasis on determining the abilities, skills, and motivational factors for employment of individuals with deteriorated work ability due to substantial chronic medical conditions. In this study, we included all consecutive patients referred for evaluation who entered the clinic between May 2018 and May 2019. We used a sample size of 177 participants (women n = 99 and men n = 78). Their mean age was 47.1 years [range 19–61 years, standard deviation (SD) 10.4]. All questionnaires were administered to the same sample, but not all participants completed all measures, resulting in different sample sizes for different instruments. The study was approved by the Ethics Committee of the Satakunta district (SATSHP/1192/13.01/2018).
The individuals who entered the clinic had a history of chronic illness, mainly musculoskeletal disorders, as confirmed by a physician. Their work ability had started to deteriorate, and work disability was probable. The rehabilitation evaluation was conducted by a multi-professional team consisting of a physician, a rehabilitation counselor or social worker, a physiotherapist, an occupational therapist, and a psychologist. The main purpose of the rehabilitation evaluation was to form a comprehensive rehabilitation plan that included medical and occupational rehabilitation interventions with an emphasis on the occupational content. The final statement of the evaluation contained a work ability assessment. The practical implementation of the rehabilitation plan was the responsibility of the individuals themselves, their employee pension insurance company, and the local employment agencies.
At entry, 15 people (10%) were working full time, 11 were working part-time (7%), 45 (30%) were unemployed, 60 (40%) were on sick leave, and 18 (12%) were receiving temporary disability pension (rehabilitation support) because of their symptoms. The average sick leave in the year preceding rehabilitation evaluation for the group was 147 days (SD 147).
This study was part of the quality register study of the Department of Physical Medicine and Rehabilitation in Satasairaala (The West Coast Quality Register). The West Coast Quality Registry uses the same questionnaires as the Swedish National Quality Registry for Pain Rehabilitation and evaluates and develops the quality of specialized pain rehabilitation clinics who treat patients with complex functional limitations requiring coordinated multimodal rehabilitation. Standardized patient surveys contain demographic data, level of education, work status and future outlook, pain intensity, psychological factors, measurements of activity/participation, and health-related quality of life [Multidimensional Pain Inventory (MPI), HAD Short Form (SF)-36, EQ-5D] (National Quality Registry for Pain Rehabilitation). All participants were requested to fill out the questionnaires at home before their first appointment at the clinic.
At the clinic, the patients were asked to estimate their functioning using the standardized International Classification of Functioning, Disability and Health (ICF) questionnaire supervised by the rehabilitation counselor, and to complete the Abilitator questionnaire by computer. The ensuing standardized rehabilitation evaluation usually took several days, after which the rehabilitation team met with the patient. During the occupational rehabilitation evaluation of the patients with chronic musculoskeletal disorders, their functional status was assessed systematically, and the rehabilitation team used an ICF-based assessment to present their final recommendations. The team recommendations for this group were full time work for 52 people (29%), occupational rehabilitation for 61 people (34%), sick leave for 33 people (19%), partial disability pension for 22 people (12%), and full time disability pension for 14 people (8%).
In this study, we assessed the relationships between four similar measures of interest. To ascertain the concurrent validity of the Abilitator, a cross-sectional study was conducted that compared the measures of functioning of the Abilitator (Wikström et al. 2020) with those obtained by the HAD scale, RAND-36, EQ-5D, and WHODAS 2.0 (short version). We also wanted to determine whether the correlations differed according to gender and age group. The age groups were based on data distribution [median (Md)]: 50 years or under and over 50 years.
The Abilitator was developed in 2015–2018 as part of a European Social Fund coordination project called Social Inclusion and Changes in Work Ability and Functioning (Solmu). The Abilitator is a self-assessment method that comprises questions grouped into well-being categories, including perceived work ability and different aspects of functioning (psychological, cognitive and social functioning, physical condition, and ability to cope with everyday activities) (Wikström et al. 2020). Because it is not a diagnostic method, it has no golden standard or specific cut-off values. The questionnaire has been translated into eight languages (plain Finnish, Swedish, English, Sorani, Arabic, Somali, Russian, and Dutch) (https://sivusto.kykyviisari.fi/en/about-the-abilitator/what-is-the-abilitator/).
The HAD is a self-assessment mood scale developed to identify the possible or probable caseness of anxiety disorders and depression among patients in non-psychiatric hospital clinics. Each subscale of HAD contains seven items. The anxiety and depressive subscales are valid measures of the severity of the emotional disorder (Zigmond & Snaith 1983). HAD has been found to perform well in assessing the symptom severity and caseness of anxiety disorders and depression in somatic (Wiglusz et al. 2016), psychiatric, and primary care patients and in general populations (Bjelland et al. 2002).
The RAND-36 is perhaps the most widely used health-related quality of life survey instrument. It comprises 36 items that assess the eight health concepts of physical functioning, role limitations caused by physical health problems (role-physical), role limitations caused by emotional problems (role-emotional), social functioning, emotional well-being (mental health), vitality/fatigue, pain, and general health perceptions (Hays & Morales 2001; Wilson et al. 2005). The International Quality of Life Assessment (QOLA) project has translated and validated the 36-item Short Form Survey Instrument (SF-36) for use in 45 countries (Ware and Gandek, 1998). It is available at no cost in the public domain (Wilson et al. 2005).
The EQ-5D comprises five questions on mobility, self-care, pain (VAS), usual activities, and psychological status and has three possible answers for each item, namely 1 = no problem, 2 = moderate problem, 3 = severe problem (Brooks with the EuroQol Group 1996; EuroQoL Group 1990). A summary index with a maximum score of 1 can be derived from these five dimensions by conversion with a table of scores. The maximum score of 1 indicates the best health state. In contrast, high scores in the individual questions indicate more severe or frequent problems. It also has a visual analog scale (VAS) to indicate general health status, with 100 indicating the best health status (Schrag et al. 2000).
The WHODAS 2.0 is based on the conceptual framework of the ICF and captures an individual’s level of functioning in six major life domains, namely cognition (understanding and communication), mobility (ability to move and get around, self-care (ability to attend to personal hygiene, dressing and eating, and to live alone), getting along (ability to interact with other people), life activities (ability to carry out responsibilities at home, work, and school), and participation in society (ability to engage in community, civil, and recreational activities). For all six domains, the WHODAS 2.0 provides a profile and a summary measure of functioning and disability that is reliable and applicable across cultures in adult populations. In addition to the total scores, WHODAS 2.0 also makes it possible to compute domain-specific scores for cognition, mobility, self-care, getting along, life activities (at home and at work), and social participation. The short version of the WHODAS 2.0 explains 81% of the variance of the 36-item version. For each domain, the 12-item version includes two sentinel items with good screening properties that identify over 90% of all individuals with even mild disabilities when tested on all 36 items. (Üstün et al. 2010). We did not include self-care aspects of the WHODAS 2.0 in this study, because there was no corresponding aspect in the Abilitator.
The HAD, RAND-36, EQ-5D, and WHODAS 2.0 are well developed and pretested measures. The evaluation of the strength of the correlations between the comparable variables of these measures determines the relative ability of the Abilitator to measure the same properties. To assess concurrent validity, the scales measuring similar concepts were expected to show moderate to strong correlations, while those gauging different concepts were expected to show weaker correlations (Hara et al. 2016).
The characteristics of the subjects and the outcomes of the questionnaires are described as mean and standard deviations (SD). The differences between genders and age groups were tested using analysis of variance (ANOVA). Concurrent validity analyses were conducted using the correlations between the Abilitator and HAD, RAND 36, EQ-5D, and WHODAS 2.0. Summary variables of the different aspects of functioning were computed from the Abilitator, HAD, RAND-36, EQ-5D, and WHODAS 2.0 to assess their association using Spearman’s rho coefficients (rs), with particular care being taken to ensure that the computed variables were indeed comparable. The agreement coefficients were interpreted as: 0 to 0.20 = poor, 0.21 to 0.40 = fair, 0.41 to 0.60 = moderate/acceptable, 0.61 to 0.80 = substantial, and 0.81 to 1.0 = near perfect (Bull et al. 2009). Data analyses used the Statistical Package for Social Sciences (SPSS version 25) program. The level of significance was set at p < 0.05.