Comparison of the responsiveness and relative effect size of the western Ontario and McMaster Universities Osteoarthritis Index and the short-form Medical Outcomes Study Survey in a randomized, clinical trial of osteoarthritis patients.
OBJECTIVE
This study compares the responsiveness and relative effect sizes of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) with the Medical Outcomes Study Short Form Health Survey (SF-36) in a randomized clinical trial for treatment of osteoarthritis (OA).


METHODS
Patients with OA of the knee or hip were randomized to receive either placebo or 2,400 mg/day of ibuprofen for 28 days. Patients completed the WOMAC and SF-36 at baseline and days 7, 14, and 28 of the trial.


RESULTS
Patients receiving ibuprofen showed significant improvement in WOMAC pain, physical functioning, and the total score, while improvement was detected only for bodily pain on the SF-36. The WOMAC detected significant differences between ibuprofen and placebo for pain and physical functioning, whereas the SF-36 detected differences for the bodily pain subscale.


CONCLUSIONS
These results suggest the WOMAC has greater power to detect treatment differences than the SF-36, with respect to pain and physical functioning, in OA clinical trials.
Davies
G M
GM
Department of Epidemiology, Merck Research Laboratories, West Point, PA 19486-0004, USA.
Watson
D J
DJ
Bellamy
N
N
D000203:Activities of Daily Living; D000368:Aged; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000627:therapeutic use*; D004311:Double-Blind Method; D015987:Effect Modifier, Epidemiologic; D005260:Female; D006801:Humans; D007052:Ibuprofen / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000145:classification / Q000188:drug therapy* / Q000503:physiopathology*; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D016896:Treatment Outcome
D000894:Anti-Inflammatory Agents, Non-Steroidal; D007052:Ibuprofen