Quality of life of patients with rheumatoid arthritis in Argentina: reliability, validity, and sensitivity to change of a Spanish version of the Rheumatoid Arthritis Quality of Life questionnaire.

The Rheumatoid Arthritis Quality of Life (RAQoL) questionnaire is the first needs-based instrument specifically designed to measure quality of life (QoL) of patients with rheumatoid arthritis (RA). The aims of our study were to develop an Argentinean version of the RAQoL and to determine its reproducibility, validity, and sensitivity to change in patients with RA. Translation process was performed according to internationally accepted methodology. Internal consistency and test-retest reliability were calculated. Criterion and construct validity were assessed by comparing the RAQoL with parameters of disease activity, the Health Assessment Questionnaire (HAQ), and the Medical Outcomes Study 36-item health survey (SF-36) questionnaire. Sensitivity to change was measured at 6-12 months using standardized response mean (SRM). The minimal important change was defined as a change of 1 or 1.96 times the standard error of measurement. A total of 97 patients with RA were included. Cronbach's α was 0.93, and test-retest reliability was 0.95. The RAQoL showed moderate to strong correlation with parameters of disease activity, the HAQ, and the SF-36. Functional status was the main determinant of patients' level of QoL. The SRM of the RAQoL was 0.24. Agreement between 20 % improvement in RAQoL and ACR20 response was moderate. Minimal important change was 2.2 (1 SEM) or 4.3 (1.96 SEM). The Argentinean version of the RAQoL is the first Spanish translation of this questionnaire. Our findings show it to be valid, reliable, and sensitive to changes in RA clinical status.