Impact of treatment duration on the effectiveness of opioid analgesia: a systematic review and meta-analysis.

Study Summary

27 randomized controlled trials (RCTs) involving patients with osteoarthritis (OA) or chronic low back pain were included in this systematic review and meta-analysis comparing opioid analgesics with placebo or opioid-minimised pain management strategies. Treatment durations were categorized as short-term (≤4 weeks), intermediate-term (4–12 weeks), and long-term (≥12 weeks). Pooled outcomes included the proportion of patients achieving clinically meaningful pain relief, defined as at least a 30% improvement from baseline, and pain intensity measured using a standardized 100-point scale. Opioids increased the likelihood of clinically meaningful pain relief during short-term treatment, but this benefit was not maintained with intermediate- or long-term use. Although opioids modestly reduced pain scores during shorter treatment periods, these improvements did not reach the predefined threshold for clinical significance. Overall, the findings suggested that opioid analgesia provided meaningful short-term benefits but offered little additional benefit over non-opioid approaches with prolonged treatment.