Objective. - To test the correlation between clinical improvements in patients with rheumatoid arthritis (RA) as defined by the American College of Rheumatology (ACR) response criteria and functional improvements as assessed by functional measures in the modified Arabic version of the Health Assessment Questionnaire (Arabic-HAQ) and to estimate the sensitivity to change of the Arabic-HAQ, in a prospective study.

Methods. - Eighty-two patients with active RA were given methotrexate and followed up prospectively for 12 months. ACR response rates and score improvements on the modified Arabic-HAQ were compared.

Results. - The Arabic-HAQ scores showed significant sensitivity to change after 6 and 12 months and were significantly correlated with the ACR response. Percentages of agreement with ACR response levels were high after 6 months and higher still after 12 months. Standardized effect sizes were 2.34 and 2.84 after 6 and 12 months, respectively. Relative efficiency of the total Arabic-HAQ score in relation to the tender joint count was greater than 1.

Conclusion. - The Arabic-HAQ is valid and sensitive to functional status changes in patients with RA. The results are comparable to those of the original HAQ. Thus, the Arabic-HAQ can be used to evaluate treatments and to identify changes that are important to RA patients.