Blog | Monday, August 13, 2012

QD: News Every Day--Viscosupplementation for knee OA doesn't work, risks side effects

Viscosupplementation for knee osteoarthritis is associated with a small and clinically irrelevant benefit and an increased risk for serious adverse events, a review showed.

Reviewers looked at randomized trials that compared viscosupplementation with sham or nonintervention control in adults with knee osteoarthritis. Results appeared in the Aug. 7 issue of Annals of Internal Medicine.

Primary outcomes were pain intensity and flare-ups. Secondary outcomes included function and serious adverse events.

Eighty-nine trials involving 12,667 adults met inclusion criteria. Sixty-eight had a sham control, 40 had a follow-up duration greater than 3 months, and 22 used cross-linked forms of hyaluronic acid.

Overall, 71 trials (9,617 patients) showed that viscosupplementation moderately reduced pain (effect size, -0.37; 95% confidence interval, -0.46 to -0.28]), which met the prespecified minimal clinically important difference of -0.37. There was a moderate degree of between-trial heterogeneity (P less than 0.001).

Trial size, blinded outcome assessment, and publication status were associated with effect size: ---Five unpublished trials (1,149 patients) showed an effect size of -0.03 (95% CI, -0.14 to 0.09). -----Eighteen large trials with blinded outcome assessment (5,094 patients) showed a clinically irrelevant effect size of -0.11 (CI, -0.18 to -0.04).
--Six trials (811 patients) showed that viscosupplementation increased, although not statistically significantly, the risk for flare-ups (relative risk, 1.51; 95% CI, 0.84 to 2.72).
--Fourteen trials (3,667 patients) showed that viscosupplementation increased the risk for serious adverse events (relative risk, 1.41; 95% CI, 1.02 to 1.97).