Do patient-reported outcome measures cover personal factors important to people with rheumatoid arthritis? A mixed methods design using the International Classification of Functioning, Disability and Health as frame of reference

Firstly, a secondary analysis of qualitative data of a previous study [29,30] was conducted. In the respective study, patients from the rheumatologic outpatient clinic of the Medical University of Vienna, Austria, diagnosed with RA [31] were asked for participation. A small sample size of 15 participants with a diverse range was aimed to gather rich and meaningful data [32]. Recruitment used a maximum variation sampling strategy [33] in terms of sex, age, former professional status and disease duration. Inclusion criteria were “being early retired” at the time of the interviews, having past employment experience (≥20 hours per week), no history of psychiatric and/or other neuro-motor disease and German as first language. Since we were interested in the identification of PFs which could be complex, such as coping or resilience, we decided to use people’s life stories and to follow the biographical narrative interpretative method (BNIM) [33,34]. In accordance to the study aim the interviews’ verbatim transcripts of the life stories were used to determine PFs which were important over the life and disease course of people with RA. Therefore, each transcript was analyzed by two researchers independently (MD, MS, and TAS). In case of disagreement, each case was discussed in a research panel of three people who together made a final informed decision, whether or not a certain PF was encompassed in the respective life story. PFs which were found among different life stories were identified based on the exploration of people’s interpretation of their life’s experience and their biography [34] and used for the exploration of their coverage by PROMs. A flow chart of the different steps of the BNIM is depicted in Figure 1. For detailed information we refer to further literature [33,34].

Finally, we determined which PFs were covered by which PROMs using the ICF [6] as reference. Items of the PROMs were linked to ICF categories by two researchers (MD and MC). In case of disagreement an informed decision was made by one further researcher skilled and experienced in the ICF linking process (TAS). The linking process followed a standard procedure by the use of the current ICF-linking rules [35]. Concerning the complexity of certain items, we applied the ICF-linking rule referring to items encompassing different constructs, an example is shown in Figure 2. Articles providing ICF categories linked to the selected PROMs were used.

The linked ICF categories of each PROM were compared to the PFs from the qualitative data by mapping them to each other. Finally, PROMs were explored in order to report how many PROMs were available to assess each PF and those PFs for which no PROM existed. An example is given in Figure 2.

Participants received information about study procedures and ethical considerations and gave written and oral informed consents. Confidentiality was guaranteed and names were changed in the given examples. The study was approved by the ethics committee of the Medical University of Vienna, Austria.

For the current study, we used the data of 15 people with RA, 11 women and 4 men with a median age of 54 years and disease duration of 11 years [29,30]. Demographic data is depicted in Table 1.

In the secondary analysis of the life stories of people with RA the following 12 PFs were identified as being important: Adaptation to changed living conditions; coping; eating habits and weight concerns; involvement into disease management; job satisfaction; meaningful activities for the individual and/or the societal context; own attitudes; reflecting about one’s life in an optimistic way; resilience; self-efficacy; sense of coherence and social appreciation.

In the following section, we give two examples of important PFs: In the life story of Hans, a 58 years old varnisher, we identified adaptation to changed living conditions. Hans did not get a job after he had left the previous one. Thus, his life story contained several descriptions on changes which were adaptations to living with RA:

“Depressing when you suddenly become useless at the age of 40, not knowing how life will go on and how to get oneself and one’s family. So, my wife worked half time and I took care of the children, as far as that was possible”. (First interview, lines 51–53)

Another example is Maria, a 42 years old woman. She did not let the disease “rule” her life and supported others to care about their health and wellbeing. Finally, Maria became an “advocate” for people with RA. We identified self-efficacy and involvement into disease management when she told about her engagement in acquiring knowledge and skills.

“What I wanted to know was how to handle it [the disease]? So, I asked my physician [rheumatologist] to prepare me for the case that the worst happens and we talked it through. I have written down everything. In the case I found myself in troubles, I looked through my notes and could help myself”. (First interview, lines 537–546)

“My ambition spurred me on, not to accept everything related to the disease and to let it rule my life. I have bought medical books, attended specialist conferences [on rheumatic diseases], I went to libraries and studied [RA specific] drugs and their side effects. I started to understand the physician a little when he talked about the medication. I felt that I could have a determining influence on the decision which drug should be tried next”. (First interview, lines 687–701) “I realized that meanwhile I was engaged in the management of my disease to the same extent as I was engaged in my job formerly”. (First interview, lines 719–721)

Three PFs were found to be important in the life stories of women only. These were reflecting about one’s life in an optimistic way, involvement into disease management and job satisfaction. While coping and meaningful activities for the individual and/or the social context was important in the life story of all men, the same was true for own attitudes in women. The frequency and percentage of identified PFs per sex are depicted in Table 2.

The systematic literature search resulted in 1280 hits, of which 831 were excluded due to 107 duplicates and 724 irrelevant articles. Finally, 449 articles were used to identify the PROMs used in RA, as described in Figure 3.

In total forty-two PROMs met our inclusion criteria. They are listed and described in Table 3.

The ICF categories linked to the items of eight PROMs [36,45,51,59,64,68,70,76] were used from existing literature [28,77,78]. The mapping of PFs to the PROMs is depicted in Table 4.

The PFs coping and reflecting about life in an optimistic way were covered most frequently (each by 14 PROMs), followed by resilience and self-efficacy (each by 12 PROMs). Compared to that, job satisfaction was not covered by any of the PROMs. The PF own attitudes was covered by six, involvement into disease management by five, sense of coherence by four and meaningful activities by two PROMs. Adaptation to changed living conditions, social appreciation and eating habits and weight concerns were covered once, each by the London Coping with Rheumatoid Arthritis Questionnaire (LCRAQ) [79].

The LCRAQ covered most (nine) PFs, followed by the General Self-Efficacy Scale (GSES) [48,49] which covered six PFs. The Arthritis Self-Efficacy Scale (ASES) [38], the Rheumatoid Arthritis Self-Efficacy Questionnaire (RASE) [67] and the Revised Ways of Coping Inventory (WOC-R) [74] captured five PFs each. Nineteen of the 42 explored PROMs covered no PF, including the different versions of the Health Assessment Questionnaire (HAQ) except the 14 Activities of Daily Living Multidimensional HAQ (14 ADLMDHAQ) [51-53,61,75], as shown in Table 4.