Clinical Immunology and Rheumatology Service, Department of Medicine and
1 Department of Biostatistics, All India Institute of Medical Sciences, New Delhi 110029, India
SIR, Measurement of functional disability is now routinely done in all outcome studies on patients with rheumatoid arthritis (RA). The Health Assessment Questionnaire-Disability Index (HAQ-DI) was originally published in 1980 by Fries et al. from Stanford University, USA [1]. Three years later, Pincus et al. published an abridged version (Modified HAQ or MHAQ), retaining only eight questions out of the original 20 and showed that MHAQ captured the same information as obtained with the somewhat lengthy original questionnaire [2]. Pincus et al. recently published a more comprehensive instrument called the multi-dimensional HAQ (MDHAQ) in which advanced activities of daily living and items related to psychological domain were added to the MHAQ [3]. Since its original description in English, the HAQ has been translated into many different languages and validated on the target populations to adapt to the local culture and life style [411]. The present study was designed to obtain a validated instrument suitable for measuring functional disability in Indian patients.
Forty patients (26 female and 14 male) newly referred to the rheumatology clinic and satisfying the American College of Rheumatology (ACR) 1987 criteria for rheumatoid arthritis were recruited from January to September, 2001. Besides the HAQ (see below), the other outcome measures constituting the ACR core-set were also obtained both at baseline and after 3 months [1]. These included tender joint count (out of 28), swollen joint count (out of 28), physician's and patient's global assessment of disease activity, pain score and Westergren erythrocyte sedimentation rate (ESR). Disease activity was measured using the DAS28 score, which was obtained at baseline and at the end of the study for each patient [12]. After complete evaluation the patients were started on standard treatment regimen, which consisted of methotrexate or sulphasalazine, steroid-bridge and non-steroidal anti-inflammatory drugs (NSAIDs).
The Indian adaptation (Table 1) was obtained by modification of the MDHAQ published by Pincus et al. [3]. MDHAQ consists of eight basic activities of daily living (ADL), six advanced ADL and four items in the psychological domain. The following modifications were carried out to obtain the Indian HAQ. One item was added to the eight basic ADL, namely, Are you able to squat in the toilet or sit cross-legged on the floor? because these two activities are so unique and relevant to the Indian culture and life style. Of the six advanced ADL, the first three only were retained. The following three ADL were excluded because these would not be applicable to most Indians: (i) Are you able to run or jog 2 miles? (ii) Are you able to drive a car 5 miles from your home? (iii) Are you able to participate in sports and games, as you would like? The psychological domain was not included because the Indian HAQ was intended to measure physical rather than psychological disability. An index based on basic 8-ADL (MHAQ of Pincus et al.) was also computed for each patient to assess the superiority of 12-ADL HAQ.
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The testretest reliability was assessed using an intraclass correlation coefficient. Student's unpaired t-test was used for calculating the sensitivity to change. Construct validity of the HAQ-DI was checked using Pearson's correlation coefficient. To assess whether 12-ADL HAQ was better than 8-ADL HAQ, paired t-test was used.
The median age of the 40 study patients was 42 yr (range 2270) and the median duration of symptoms was 17 months (range 530). Twenty of these received the English version of the HAQ and the other 20 received the Hindi version. Baseline HAQ values for English and Hindi groups were 1.21±0.48 and 1.5±0.49, respectively. the testretest reliability was very good (intraclass correlation coefficient: English 0.93, Hindi 0.73). After treatment, the HAQ values changed to 0.81±0.47 and 0.65±0.55, respectively, demonstrating a very good sensitivity to change (Student's unpaired t-test: P<0.05). Construct validity was assessed using Pearson's correlation coefficient between the corresponding values of HAQ and DAS28, both at baseline (r=0.49, P<0.05) and after intervention (r=0.62, P<0.01).
Disability index values obtained with 12-ADL HAQ were greater than those obtained with 8-ADL HAQ (1.13±0.6 vs 0.89±0.57). The difference was found to be statistically significant (paired t-test, P<0.001). Table 2 shows ADL-wise mean scores for all the patients at baseline and after 3 months. It is evident that the highest disability scores were recorded in response to item no. 6, i.e. squatting in the toilet and sitting cross-legged on the floor. Moreover, the highest proportion of patients (85%) scored at least 2 (much difficulty) for this ADL. Even after 3 months of treatment a majority of patients (60%) still suffered from this disability. The mean scores for the three advanced ADL were also relatively high. It is also noteworthy that only 7.5% of patients had similar levels of difficulty in lifting a full cup or glass to their mouth.
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The study shows that the Indian HAQ is a reliable, sensitive and valid instrument for measuring functional disability in RA. It can be self-administered in English or Hindi. Since it takes only about 3 min to complete, it is eminently suitable for busy rheumatology clinics. It is hoped that the Indian HAQ will be used widely on the Indian population both at home and abroad.
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References
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