Objective: The purpose of the present investigation was to explore a modification of the Health Assessment Questionnaire (HAQ) to capture the functional problems associated with psoriasis as well as inflammatory arthritis in patients with psoriatic arthritis (PsA).
Methods: During a visit to the Psoriatic Arthritis Clinic, 118 patients with PsA were asked to complete the modified version of the HAQ. The original HAQ and expanded HAQ (HAQ-SK) scores were calculated. Correlation and regression analyses were used to examine the relationship between the severity of psoriasis and the functional status as measured by the various HAQ measures.
Results: The mean global HAQ score was 0.55 on a scale ranging from 0 to 3, while the mean global HAQ-SK score was 0.56, suggesting that the modification, which involved adding items to reflect those aspects of physical functioning most affected by psoriasis, did not materially change the global HAQ score. There were no significant associations between the global HAQ-SK disability score or the added psoriasis items and the severity and activity of psoriasis, as measured by the Psoriasis Area and Severity Index (PASI) (all correlations < 0.20). The only significant association was found between the patient and the clinician ratings of psoriasis severity (r = 0.49). Open-ended questions suggest that psychosocial functioning is another dimension of health status which is of concern to PsA patients.
Conclusion: The findings suggest that physical disabilities associated with the severity and activity of psoriasis are not captured by the HAQ or the HAQ-SK. Psychosocial functioning, an additional area of concern to PsA patients, is also not directly linked to physical functioning or to the severity of psoriasis.