Objective: To compare the validity and reliability of a graphic rating scale (GRS) and a verbal rating scale (VRS) for measuring pain intensity in young female Egyptian and Dutch patients with rheumatoid arthritis (RA).
Methods: Data were obtained in a cross-cultural study of 42 Egyptian and 30 Dutch female outpatients with stable RA. Construct validity was assessed by correlating the scales with other core measures of disease activity in RA. Test-retest reliability was assessed over a 1-week interval.
Results: The GRS and the VRS were strongly intercorrelated in the total study cohort and in the Egyptian and Dutch subgroups. In the individual subgroups, only the GRS demonstrated the expected pattern of correlations with other disease activity measures. Test-retest reliability of the GRS was adequate in both Egyptian and Dutch patients (intraclass correlation coefficient 0.78 vs. 0.83, respectively), whereas reliability of the VRS was unsatisfactory in the Egyptian subgroup (weighted kappa 0.60 vs. 0.82 in the Netherlands).
Discussion: The study confirmed that the GRS and VRS were reliable and valid in the total study cohort. Within the individual countries, the GRS seemed to perform better than the VRS.