Patients with primary knee osteoarthritis (OA) who were taking risedronate showed improvements in joint structure and symptoms.

That was the primary finding from a British 1-year prospective, double-blind, placebo-controlled study of risedronate in structure and symptoms of knee OA (BRISK). The study enrolled 284 intention-to-treat patients (age 40-80) with mild to moderate OA of the knee's medial compartment.

Patients were randomized to once-daily risedronate (5 mg or 15 mg) or placebo. Radiographs were assessed at baseline and one year to measure joint space width. Pain, function, and stiffness were assessed using the Western Ontario and McMaster Universities (OA) index. Those receiving risedronate, 15 mg, showed improvements, particularly in physical function, significant improvement of patient global assessment (p<0.001), and decreased use of walking aids relative to patients receiving placebo (p=0.009).

Eight percent of patients receiving placebo and 4% of patients receiving risedronate, 5 mg, exhibited detectable progression of disease versus 1% of patients receiving 15 mg (p=0.067). Risedronate, 15 mg, significantly reduced markers of cartilage degradation and bone resorption.

"Drugs to treat osteoporosis may have beneficial effects on other common age-related diseases, such as OA, which involve bone," commented Tim Spector, MD, MSc, FRCP, director of the Twin Research & Epidemiology Unit, St. Thomas Hospital, London, United Kingdom. He said that while he was surprised "to find such a consistent effect in a short timeframe of 12 months," he was "disappointed" that results in other populations have not shown the same benefit as the UK population.

The study was sponsored by a grant from Procter and Gamble Corp.