The smallest worthwhile effect on pain intensity of nonsteroidal anti-inflammatory drugs and exercise therapy for acute and chronic low back pain: a benefit-harm trade-off study

Question: What are the smallest worthwhile effects of nonsteroidal anti-inflammatory drugs (NSAIDs) for people with acute and chronic low back pain (LBP)? What is the smallest worthwhile effect of individualised exercise for people with chronic LBP compared with no intervention? Design: Benefit-harm trade-off study. Participants: Participants were recruited by advertisement on social media and included if they were English-speaking adults in Australia who had non-specific LBP. Outcome measure: Pain intensity. Results: A total of 116 people with acute LBP and 230 people with chronic LBP were recruited. For acute LBP, the smallest worthwhile effect of NSAIDs additional to no intervention was a 30% (IQR 10 to 40%) reduction in pain intensity. For chronic LBP, the smallest worthwhile effect of NSAIDs additional to no intervention was a 27.5% (IQR 10 to 50%) reduction in pain intensity. For chronic LBP, the smallest worthwhile effect of exercise additional to no intervention was a 20% (IQR 10 to 40%) reduction in pain intensity. There were small associations between baseline pain, duration of pain and level of exercise and the smallest worthwhile effect of NSAIDs for acute LBP. There were no other clear associations. Conclusions: For people with LBP, the smallest worthwhile effect of exercise and NSAIDs additional to no intervention is approximately a 20 to 30% reduction in pain. These results can inform the interpretation of the effects of NSAIDs and exercise in randomised trials and meta-analyses, incorporating consumers’ perspectives. Further research on comparisons between different interventions and on other core LBP outcomes may inform decision-making. Registration: OSF osf.io/3erjx/.