A recent review of guidelines for the management of osteoarthritis has highlighted the agreement of recommendations across guideline organisations regarding the pharmacological treatment of osteoarthritis . Acetaminophen (paracetamol) is consistently recommended as the mainstay frontline analgesic for treating non-inflammatory pain (in addition to non-pharmacological interventions such as education, self-management and exercise), with NSAIDs as the second line analgesic. However, this recommendation appears to be based on limited evidence in terms of direct comparisons between NSAIDs and paracetamol, which would be most informative for clinical decision making. A review published in 2004 identified more guidelines (n=9) than trials (n=5) directly comparing NSAIDs to paracetamol in patients with osteoarthritis, highlighting gaps in the quantity and quality of evidence . Based on three trials of adequate methodological quality, this review showed a small difference in pain relief in favour of NSAIDs compared with paracetamol (standardised mean difference -0.33, 95% confidence interval -0.51 to -0.15). Similarly in back pain, a Cochrane review identified only three trials with direct comparisons, demonstrating a small benefit for NSAIDs compared with paracetamol (standardised mean difference -0.21, 95% confidence interval -0.43 to 0.02) .
Over the past 10 years numerous guidelines have been published, while the evidence base has also expanded. A more recent meta-analysis identified 15 trials in hip or knee osteoarthritis still showing small benefits of NSAIDs over paracetamol (pooled effect size: -0.29 (95% confidence interval -0.35 to -0.22) . New trials are unlikely to sway the evidence for the effectiveness of NSAIDs for non-inflammatory pain, or change guideline recommendations. However, there still is a lack of data on long-term outcomes, inadequate reporting of safety data, potential publication bias, and relatively few head-to-head comparisons . More advanced approaches to meta-analysis, including trial sequential analysis and network meta-analysis, enable the estimation of comparative effectiveness and ranking of treatment options, providing more useful information to clinicians and patients when making decisions regarding pain relief [e.g. 5]. The lecture will discuss the usefulness of these approaches and how they may inform treatment guidelines or offer guidance regarding the design of future trials.
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Disclosure of Interest None declared