TY - JOUR T1 - Minimal Important Difference and Responsiveness to Change of the SF-36 in Patients with Psoriatic Arthritis Receiving Tumor Necrosis Factor-α Blockers JF - The Journal of Rheumatology JO - J Rheumatol SP - 2077 LP - 2079 DO - 10.3899/jrheum.101256 VL - 38 IS - 9 AU - YING-YING LEUNG AU - TRACY YANER ZHU AU - LAI SHAN TAM AU - EMILY WAI-LIN KUN AU - EDMUND KWOK-MING LI Y1 - 2011/09/01 UR - http://www.jrheum.org/content/38/9/2077.2.abstract N2 - To the Editor:The Medical Outcome Health Survey Short-form 36 (SF-36) has been validated in psoriatic arthritis (PsA)1 and its psychometric assumptions tested2,3, but no data on its minimal important difference (MID) exist. MID is the smallest change in a patient-reported outcome (PRO) score that patients perceive as a meaningful change4. It differentiates treatment response and may serve as threshold for therapy change. We examineed the MID and responsiveness to change of SF-36 scales in patients with psoriatic arthritis (PsA) undergoing treatment with tumor necrosis factor-α (TNF-α) blockers.Twenty consecutive patients with active PsA fulfilling the CASPAR criteria5 were recruited to receive TNF-α blockers. After 12 weeks, 9 patients continued TNF-α blockers (Group 1); 11 patients discontinued due to financial constraints. PRO including pain, patient’s global health assessment (PGA), Health Assessment Questionnaire (HAQ)6, and SF-367 were collected at baseline and Weeks 12, 24, 36, and 52. At each visit, patients answered an anchor question on general health status, “How do you rate your current health status as compared to last visit: (1) much better, (2) slightly better, (3) similar, (4) slightly worse, and (5) much worse.” The differences in PRO scores between 2 consecutive visits (e.g., Week 12 – Week 0, Week 24 – Week 12) were calculated. In 4 followups, 78 sets of PRO scores were analyzed. MID estimates were calculated as the mean change of PRO variables in those who … Address correspondence to Dr. Y-Y. Leung, Department of Medicine and Geriatrics, Tai Po Hospital, HKSAR, 9 Chuen On Road, Tai Po, NT, Hong Kong. E-mail: katyccc{at}hotmail.com ER -