A Comparison of the Efficacy and Safety of Nonsteroidal Antiinflammatory Agents Versus Acetaminophen in the Treatment of Osteoarthritis: a Meta-analysis

Objective: To perform a meta-analysis comparing the efficacy and safety of recommended dosages of nonsteroidal antiinflammatory drugs (NSAIDs), including cyclooxygenase 2 inhibitors, versus acetaminophen in the treatment of symptomatic hip and knee osteoarthritis.

Methods: Medline and EMBASE searches were performed for original clinical trials directly comparing NSAIDs with acetaminophen. A standardized form was used to abstract all data, including outcome measures of pain at rest, walking pain, and dropouts due to adverse effects. Inverse-variance-weighted mean differences (WMDs) and 95% confidence intervals (95% CI) for pain measures were determined for treatment groups. Odds ratios (ORs) and 95% CIs were calculated for withdrawals due to adverse events. Results were compared using a random effects model.

Results: Seven articles met inclusion criteria with sufficient data for analysis. Participants had a mean age of 61.1 years and 71.1% were women. Test of heterogeneity was not significant for either rest (P = 0.73) or walking (P = 0.76) pain. The scores for overall pain at rest (WMD -6.33 mm on a 100-mm visual analog scale [VAS], 95% CI -9.24, -3.41) and walking pain (WMD -5.76 mm on a 100-mm VAS, 95% CI -8.99, -2.52) favored the NSAID-treated group. Although NSAIDs elevated the risk of withdrawals due to adverse events, the difference was not statistically significant (OR 1.45, 95% CI 0.93, 2.27).

Conclusion: NSAIDs are statistically superior in reducing rest and walking pain compared with acetaminophen for symptomatic osteoarthritis. Safety, measured by discontinuation due to adverse events, was not statistically different between NSAID- and acetaminophen-treated groups.