The nonsteroidal anti-inflammatory drug diclofenac (sold as Arthrotec or Voltaren) may have harmful effects on cartilage in people with Osteoarthritis (OA) of the knee and hip, a new study hints. But whether this effect is mediated by a reduction in pain that results in increased use of the joints or reflects a true harmful effect remains to be established.

Osteoarthritis is a common age-related disease marked by degradation of joint cartilage. OA of the hip and knee can be particularly disabling because of the related pain and functional impairment. NSAIDS are widely used to relieve pain of OA.

The results of some studies have suggested that NSAIDs may be toxic to arthritic joints, but other reports have yielded conflicting results.

To investigate further, Dr. M. Reijman and colleagues at Erasmus Medical Center in Rotterdam evaluated data on close to 1700 individuals with OA of the hip and 635 with OA of the knee. All of them were aged 55 years or older and all underwent a baseline joint exam between 1990 and 1993.

After an average follow-up period of 6.6 years, progression of disease was observed in 10.5 percent of patients with hip OA and 26.0 percent of those with knee OA.

According to the team, long-term use of diclofenac (for greater than 180 days) was significantly associated progression of disease, even after adjusting for age, gender, body mass index (BMI), and baseline disease status.

“Our data suggest that diclofenac may not be harmless and may induce accelerated progression of hip and knee OA,” the investigators conclude in the journal Arthritis and Rheumatism. There is a “clear need” for more study on the effects of NSAIDs on cartilage, they add.

SOURCE: Arthritis and Rheumatism October 2005.