CONSISTENCY AND VALIDITY OF PATIENT ADMINISTERED ASSESSMENT OF QUALITY-OF-LIFE BY THE MOS SF-36 - ITS ASSOCIATION WITH DISEASE-ACTIVITY ANDDAMAGE IN PATIENTS WITH SYSTEMIC LUPUS-ERYTHEMATOSUS

Objective. To investigate the metric properties and validity of the as sessment of quality of life by the MOS Short Form 36 (SF-36) in patien ts with systemic lupus erythematosus(SLE) and to examine the effect of disease on quality of life. Methods, Cross sectional study of 150 pat ients with SLE (age: mean 39.7 yrs, SD 11.4 yrs; 95% female) attending 2 specialist lupus clinics between November 1994 and April 1995. Shor tly before or after the consultation patients completed the SF-36 and the MOS SF-20 with an additional question about fatigue (SF-20+) in ra ndom order. Disease activity was measured by the British Isles Lupus A ctivity Group system (BILAG), disease damage by the Systemic Lupus Int ernational Collaborating Clinics/American College of Rheumatology (SLI CC/ACR) damage index (SLICC). Results, SF-36 domains were shown to be internally consistent (Cronbach's coefficient alpha greater than or eq ual to 0.71), Significant associations of the SF-36 domains with the c orresponding domains of the SF-20+ and with global disease activity me asured by BILAG were observed. SF-36 scores in patients with SLE were significantly lower than in controls. Different disease activity level s were significantly associated with different quality of life scores, with excellent ability to record the continuum from good health to se rious illness by the SF-36. Disease activity had greater effect on qua lity of life than age, cumulative damage, or disease duration. Conclus ion, This study shows the SF-36 is internally consistent and proves co nstruct, discriminatory, and criterion validity for the SF-36 and cons truct validity for the SF-20+ in patients with SLE. The SF-36 is prefe rred because of its broader scope of questions, its widespread use, an d previous international validation for a wide variety of diseases.