Comparison of the health assessment questionnaire and arthritis impact measurement scale in patients with psoriatic arthritis

Objective. To determine which of two instruments, the Health Assessment Questionnaire (HAQ) and the Arthritis Impact Measurement Scales (AIMS), was more closely correlated with the main parameters reflecting activity and severity of psoriatic arthritis. Methods. Both instruments were administered to 72 consecutive patients with psoriatic arthritis. Results. Global HAQ and AIMS scores,were closely correlated with each other (r(s) =0.747; P<0.00001). AIMS physical function scales namely physical activity, dexterity, social activity and activities of daily living - were moderately or closely correlated with the main clinical disease activity parameters, most notably morning stiffness of axial joints (r(s)= 0.271-0.551). Scales measuring psychological status yielded weaker correlations with disease activity parameters (r(s)= 0.241-0.277) and were also correlated with the visual analog scale score for skin lesion severity. Morning stiffness of peripheral joints was correlated only with two AIMS scales, namely pain (r(s)= 0.532) and activities of daily living (r(s)= 0.303). Severity of radiological damage of peripheral and axial joints was most closely correlated with the scales of physical function, most notably physical activity. The global and scale HAQ scores showed moderate to close correlations with the main clinical disease activity parameters, most notably morning stiffness of axial joints. The global HAQ score was also correlated with radiological carpal involvement and with the radiological severity of peripheral joint involvement, whereas only the arising and hygiene scales were (moderately) correlated with the radiological severity of spinal involvement. Conclusion. Although both the HAQ and the AIMS were useful in assessing health status in psoriatic arthritis patients, only the AIMS captured some of the effects of the skin lesions. Our data also suggest that the AIMS may be more effective than the HAQ for evaluating the effect of radiological lesions produced by psoriatic arthritis.