To establish a questionnaire for quantification of hand involvement in osteoarthritis (OA) of the hands and rheumatoid arthritis (RA) meeting daily routine requirements.
The smallest number of questions of the modified score for the assessment and quantification of chronic rheumatic affections of the hands (M-SACRAH) providing reasonable reliability was identified by factor analysis and calculating Cronbach's alpha, subsequently resulting in a five-item scale, the short form-SACRAH (SF-SACRAH), which was then administered to 176 RA and 71 hand-OA (HOA) patients simultaneously with the M-SACRAH. Additionally, patient's satisfaction (PatSAT) with disease status was assessed (according to the Austrian school marking system from 1 to 5). Gamma was calculated to assess the agreement of the SF-SACRAH with the M-SACRAH and between the single corresponding questions of different formats. The Wilcoxon rank test was applied to estimate the relationship between PatSAT and the SF-SACRAH.
Alpha for the SF-SACRAH in 176 RA and 71 HOA patients amounted to 0.869 and to 0.897, respectively, indicating high internal consistency. In both patient groups the SF-SACRAH was found to be significantly correlated to the M-SACRAH (both P(s)<0.01). Agreement between the corresponding questions of both scales was significant in both patient groups by calculating gamma (average gamma 0.683 in HOA and 0.847 in RA). PatSAT and SF-SACRAH values were highly significantly correlated (P<0.001) proving the score's external validity.
The SF-SACRAH proved to be a brief and practicable tool to assess hand involvement in OA and RA meeting the requirements of daily routine.