Double-blind preference and compliance multicentre study in osteoarthritis: once-a-day treatment

Two-hundred-and-three female patients (mean age: 58 yrs; SD: 8.2 yrs) suffering from osteoarthritis entered this late phase IV multicentre, stratified according to previous therapy (e.g. ketoprofen, naproxen, aspirin, indomethacin or indoprofen), randomized, double-blind, between within-patient trial of 2-week duration. Each patient received either diclofenac SR 100 mg/day (D), piroxicam 20 mg/day (P), or placebo (P1 by oral route. Clinical evaluation (functional class; pain assessment; osteoarthritic condition; joint motility and stiffness) was performed at entry, as well as after the first and the second week. Patient compliance and reported signs and symptoms were recorded after the first week and at the end of the trial. Patient preference, as regards previous therapy, and global evaluation (both by the physicians and the patients) were checked at the end of the trial. The clinical evaluation showed a superiority of D and P over P1. No difference was seen between the two active drugs. Placebo effect was very strong. Global evaluation was significantly in favour of D and P. Patient compliance was extremely good (greater than or equal to 95%). Diclofenac was preferred to naproxen, aspirin and indomethacin, while piroxicam and placebo were preferred only to aspirin. The tolerability of the two active drugs was good and comparable. A significantly lower number of patients complaining of unwanted effects (u.e.) was detected in the placebo group. The number of patients withdrawn for u.e. was similar in the three trial groups.