Background
Rheumatoid arthritis (RA) is a chronic autoimmune disorder affecting joints and surrounding tissues [
1]. Most commonly, RA results in swollen, hot and painful joints and generalised stiffness, which worsens with rest. The hands and wrists are the most commonly affected joints. Typically, metacarpophalangeal (MCP) and proximal interphalangeal (PIP) joints become swollen and painful. As a result, people struggle with daily activities requiring gripping, pinching and carrying. If unresolved, these difficulties may lead to activity limitation, participation restriction and loss of independence in later life [
2]. Therefore, early recognition and rehabilitation of hand pain and problems may help to improve people with RA’s future health and quality of life.
The National Institute for Clinical Excellence (NICE) Guidelines for the Management of Adults with RA [
3] recommend that patients should have access to specialist occupational therapy if they have difficulties with hand function. To maintain or improve these abilities, occupational therapists need to effectively identify individual’s difficulties and evaluate therapy outcomes. To this end, valid, reliable patient-informed Patient Reported Outcome Measures (PROMs) that are relevant to the interventions rheumatology occupational therapists provide are necessary, but there is only one appropriate measure is currently validated for use in the UK [
4]. Several self-reported measures of hand function are available for use in RA [
5‐
8] however these did not involve patients in their development [
9]. It is increasingly recognised that patients should inform the development of such measurement tools [
10] to ensure that issues most relevant and important to them are included.
The Measure of Activity Performance of the Hand (MAP-Hand) questionnaire is an 18-item PROM of hand activity performance, which was developed and rigorously tested in Norway. It has good evidence of reliability and validity in Norwegian people with RA (
n = 134) [
9]. To ensure items were representative of normal hand function, items were matched to the eight main handgrips using the Sollerman handgrip classification [
11]. Rasch analysis was used to finalise the 18-itemstructure representing a range of item difficulty. The scale is unidimensional and has a high person separation index of 0.93. Test-retest reliability is good (ICC = 0.94) although only conducted with 34 people. The MAP-Hand significantly correlated with the AIMS
2 hand and finger function (
r = 0.78) and arm scales (
r = 0.66) [
9]. Following testing the MAP-Hand was translated into North American English in accordance with the recommended translation procedures for scale development [
9]. The MAP-Hand developers recommended further testing in different countries to establish its psychometric properties and cultural validity.
Linguistic translation of self-administered questionnaires for use in different cultural contexts is insufficient [
12,
13]. Researchers must also ensure cross-cultural adaptation to establish items are relevant and understandable to the population of interest, and whether additional items need including to avoid systematic bias [
12]. Once adapted, further psychometric testing is required to ensure content validity and reliability is retained across different cultures [
12,
13]. Beaton et al. [
12] published guidelines for cross-cultural adaptation of self-report measures to standardise this process. A decade following this, Consensus-based Standards for the selection of health Measurement Instruments (COSMIN) checklist was developed to evaluate the methodological quality of the studies reporting measurement qualities [
14,
15]. More recently COSMIN methodology for evaluating the content validity of patient-reported outcome measures were proposed as a rating system to summarise the evidence of a PROM’s content validity [
16]. This is deemed to be more detailed, standardised, and transparent than earlier published guidelines, including the previous COSMIN standards [
16].
The overall aim of this study was to develop a British English version of the MAP-Hand following the recommended linguistic and cultural adaptation guidelines and test its psychometric properties (internal consistency, construct and concurrent validity, test-retest reliability and minimal detectable difference) using both the classical testing theory and item response theory in a UK population of people with RA.
Discussion
The British English MAP-Hand is a brief, valid and reliable measure of hand activity performance, which can be completed in an average of 2 minutes by people with RA. Due to its ease of use and precision it is an ideal questionnaire to utilise in busy clinical environments, such as the NHS outpatient rheumatology and hand therapy clinics. As a psychometrically robust measure, it can be used to evaluate clinical outcomes, for research purposes, and to describe the patterns and extent of hand activity performance in people with RA in the UK.
Implications for clinical and research practice
The British English MAP-Hand correlated highly with the HAQ20 and ULHAQ [
4]. Although these outcomes are measuring similar constructs, the MAP-Hand was developed using patient generated items and this is reflected in the way in which the functional limitation is defined and scores are calculated. For instance, the hand activity performance is measured in the MAP-Hand at a person-level functioning (activity) [
52] with or without the use of aids and adaptations (i.e. gadgets). This means that the MAP-Hand functional limitation score does not increase when the responder appraise their ability to do an activity such as “Writing by hand” (item 15) as “No difficulty” due to their use of pen grip to reduce pain and ease function. People with RA are increasingly encouraged to self-manage their condition, which includes adherence to joint protection advice, that may require behavioural modifications and the use of aids and environmental adaptations [
53]. In the hands PIP, thumb interphalangeal (IP) and Distal Interphalangeal (DIP) joints are most involved in executing tasks, hence the use of gadgets such as adapted cutlery, can and bottle opener, zip puller and button hooks are recommended by occupational therapists to encourage joint protection and decrease dependency on others to help with such activities (i.e. the need for help and assistance), decrease pain and prevent joint damage. Therefore use of aids and environmental adaptations are viewed as enablers of function and independence, rather than a marker of disability. Nevertheless, the scoring system used within the HAQ [
21,
22] increases with the use of special device by 1 point, if the patient ‘needs’ help from others to do an activity by 2 points and if the patient usually needs both a special device and help from another person by 3 points [
54]. Moreover, permanent adaptations of the person’s environment (e.g. changing faucets in the bedroom or kitchen, using Velcro closures on clothing) are also counted as aids and devices [
54]. This means, even if the responder has chosen to appraise their ability to do an activity as “without any difficulty” [scored 0] due to their use of aids and adaptations to enable function, their disability score will increase when they disclose the use of aids to help their functioning, unlike how the MAP-Hand is scored.
Another comparative scale that is commonly used in clinical and research practice and recently culturally validated for use in the UK is DASH [
4]. DASH scores were also highly correlated with the MAP-Hand scores in this study (Table
6). DASH is a considerably larger, comprehensive scale of upper limb function, which also includes optional modules for assessing upper limb performance at work (WORKDASH) and measuring abilities and symptoms of athletes and performing artists (SPAMDASH). The optional modules are scored separately [
4]. As the MAP-Hand, the DASH scores are calculated based on the responder’s ability, regardless of how they do the task. However, unlike the MAP-Hand the DASH includes items measuring both activity limitation (person-level) and participation restriction (societal-level) and as well as the activities performed using hands, the arm and shoulder function is also measured. Although DASH is a comprehensive assessment including 30 items, QUICKDASH is available as a shorter version and consists of 11 items (6 daily activity ability; two symptoms (pain and tingling); and three participation) [
4,
55]. Therefore, although the MAP-Hand and the DASH questionnaires appear to measure the same construct at a first glance, their remits differ at conceptual and measurement level and clinicians and researchers should take these differences into consideration if they are having to choose the use of one measure over the other.
Table 6
Internal consistency and test-retest reliability of the British English MAP-Hand [Classical Testing]
MAP-Hand | 0.96 | 273 | 17.61 [11.65] | 17.08 [11.53] | 0.96 (0.94,0.97) |
Statistical analysis
In this study the unidimensionality of the MAP-Hand was challenged by the CFA, but supported by the Rasch analysis. In both cases, substantial adjustments had to be made to accommodate the local dependency of the item set. The clusters of locally dependent items made clinical sense, grouping items with similar functional requirements, such as opening jars or cans.
Differential item function may also have contributed to the disturbance of dimensionality. The presence of DIF is not uncommon in health status measures of functioning [
56]. The fact that, at any level of hand function males had more difficulty tying shoelaces may simply reflect that women are less likely to wear shoes with laces. Also that at any level of hand function, women have more problem opening jars may simply be a function of men having stronger grip. However at the scale level, the item DIF was cancelled out and, so as long as all 18 items are administered, the total score should remain unaffected.
In the analysis of the local independence, assumption took prominence, which was not reported in the original validation. This can inflate reliability, although in this case only marginally, and the level of reliability remained high, consistent with individual use. By using a testlet solution to absorb the local dependency, a satisfactory fit was achieved. The metric conversion that follows good fit will allow for an appropriate calculation of change scores, as well as aspects such as the minimal important difference, the calculations of which are invalid on ordinal scales [
57].
Limitations
We only tested the British MAP-Hand in people with RA. Further testing of the British MAP-Hand in other conditions is needed to ensure the scale has validity and reliability for use in these conditions. In addition, further studies should consider longitudinal design with multiple follow-up points to test the British English MAP-Hand’s ability to detect change in hand function over time (i.e. Responsiveness).
Acknowledgements
The authors wish to thank all the study participants; Robert Peet and Kate Woodward-Nut, Centre for Health Sciences, University of Salford, for assistance with data collection and data entry; and all the Principal Investigators, rheumatology consultants, rheumatology and research nurses and occupational therapists assisting with participant recruitment and study support at the participating sites: Prof Terry O’Neill, Ann McGovern, Jennifer Green, Angharad Walker (Salford Royal Hospital); Prof Ian Bruce, Lindsey Barnes, Elizabeth Beswick, Sarah Evans (Manchester Royal Infirmary); Dr. Leena Dass, Dr. Sophia Naz, Lorraine Lock (North Manchester General Hospital); Dr. Chris Deighton, Alison Booth, Jo Morris (Royal Derby Hospital); Prof David Walsh, Debbie Wilson, Jayne Smith (Kings Mill Hospital, Sherwood Forest Hospitals NHS Foundation Trust); Dr. Chetan Mukhtyer, Loretta Dean, Susan Rowell (Norfolk and Norwich Hospitals); Dr. Bela Szenbenyi, Carol Gray (Diana Princess of Wales, Grimsby); Dr. Mike Green, Anne Gill, Lisa Carr (York Hospital); Dr. Kirsten Mackay, Julie Easterbrook, Liz Burnett (Torbay Hospital); Dr. Mike Green, Alison Miernik, Rachel Bailey-Hague (Harrogate District Hospital); Dr. Atheer Al-Ansari, Jayne Edwards, Julia Nicholas (Robert Jones & Agnes Hunt Hospital, Oswestry); Dr. Wendy Holden, Janet Cushnaghan, Angie Dempster, Hayley Paterson (Basingstoke and North Hampshire Hospital); Mr. David Johnson, Lindsey Barber, Jan Smith (Stepping Hill Hospital); Dr. Karen Douglas, Lucy Kadiki, Chitra Ramful, Daljit Kaur (Russell Hall Hospital, Dudley); Dr. Anca Ghiurlic, Christine Graver (Royal Hampshire Hospital, Winchester); Dr. Frank McKenna, Jane McConiffe (Trafford Hospitals); Dr. Sophia Naz and Lorraine Lock (Fairfield Hospital).