To evaluate the Health Assessment Questionnaire (HAQ) in the assessment of functional status, its responsiveness to change with treatment and its correlation with conventional disease activity indices in polymyalgia rheumatica (PMR).
Newly diagnosed patients with PMR, satisfying modified Jones and Hazleman criteria, were recruited to the study. The clinical assessments, including early morning stiffness (EMS), pain measured on a horizontal 10 cm visual analogue scale (VAS), C-reactive protein (CRP) and the HAQ, were carried out 0, 6, 12 and 24 weeks after treatment had been started. Any comorbid condition likely to affect the HAQ was noted.
Eighteen patients completed the 6-month assessment period. These included four males and 14 females, with a mean age of 68.5 years. Pretreatment mean disease activity showed EMS of 68 min, VAS pain of 69 mm, CRP of 46 mg/l and a HAQ score of 1.57. At 6 months, mean EMS had declined to 4 min, VAS pain to 11 mm, CRP to 9 mg/l and the HAQ score to 0.14. Linear regression analysis of HAQ vs EMS, VAS and CRP showed correlation coefficients of 0.72, 0.66 and 0.63, respectively. Standardized response means (SRM), a measure of responsiveness, for HAQ, EMS, VAS and CRP were 3, 1.7, 1. 8 and 1.6, respectively. We assessed each section of the HAQ individually to see if any particular daily activity was more responsive to change. Questions on dressing and grooming, rising and eating were more responsive to change (SRM 2.5, 2.7 and 1.8, respectively) than questions about walking, hygiene, reach, grip and activities (SRM 0.8, 1.4, 1.2, 1.1 and 1.1, respectively).
The HAQ is useful in the assessment of functional status in PMR, is responsive to change and correlates well with conventional indices of disease activity. However, fixed disabilities like osteoarthritis, shoulder capsulitis and systemic diseases may affect its interpretation. The sections of the HAQ measuring disability related to inflammatory stiffness/proximal involvement showed greater responsiveness to change than other sections, and hence may have a greater role in evaluating disease activity in PMR.