Development of a questionnaire to investigate patient compliance with antirheumatic drug therapy

To develop a rheumatology oriented questionnaire that measures compliance to drug regimen and identifies factors that contribute to suboptimal compliance in patients with rheumatoid arthritis (RA), polymyalgia rheumatica (PMR), and gout.

Thirty-two patients (16 RA, 8 PMR, 8 gout) participated in semistandardized home interviews about their attitude toward their antirheumatic medication, actual drug intake, and reasons for not taking medication. A focus group interview with 7 patients (3 RA, 2 PMR, 2 gout) was held. Following an advertisement in the rheumatology patient organization magazine (>8000 patients) 14 patients (9 RA, 5 PMR) telephoned and explained their reasons for noncompliance. All interviews were recorded on tape, transcribed, and independently reviewed by 2 investigators. Thirty-one statements were selected. After a field test, the phrasing of some items was revised. The questionnaire was then sent by mail to 117 consecutive outpatients (58 RA, 30 PMR, 29 gout).

Twelve items were excluded because of low or high corrected item-total correlation or skew distribution of the answers. Internal consistency of the remaining 19 items was intermediate (0.71). Discriminant analyses with an overall patient self-report compliance measure showed a sensitivity of 98%, a specificity of 67%, and a Cohen's kappa of 0.71. Stepwise discriminant analyses revealed that 3 items classified 84% of all cases correctly with a sensitivity of 99%, specificity 80%, and kappa 0.78.

The 19 item measure was well accepted. It is useful to detect possible barriers for optimal compliance and to predict patient compliance to drug regimen.