This systematic review investigated various sources of heterogeneity
(statistical, clinical, and methodological) of RCTs evaluating
the effectiveness of acetaminophen vs NSAIDs in patients with knee
and hip OA in relation to pain outcomes. We found moderate
clinical heterogeneity for the five studies that included both hip
and knee OA. Unfortunately, data on knee and hip OA
were not presented separately in the available studies. Our forest
plot showed a higher effect size in favor of NSAIDs in studies that
included a higher percentage of patients with hip OA. Svensson
et al. also found differences in effectiveness in patients with hip and
Table II
Risk of bias assessment of included RCTs
knee OA treated with naproxen. Yet,