Background Opioid use can heighten pain perception over time. Aim To determine whether the effectiveness of opioid analgesia diminishes with treatment duration in those with chronic low back pain or osteoarthritis. Design and setting Systematic review (January 22, 2025) of randomized trials comparing opioids to placebo/opioid-minimized pain management strategies in those with chronic low back pain or osteoarthritis. Methods Random effects meta-analysis using MEDLINE, EMBASE, CENTRAL, and Scopus databases. OUTCOMES: Primary: Attainment of clinically important pain relief (≥ “moderate” or ≥30% improvement). Secondary: On-treatment pain (100-point scale). PRIMARY ANALYSIS: Difference in primary/secondary outcomes across short-term (≤4-weeks), intermediate-term (4-12 weeks), and long-term (≥12 weeks) subgroups. Results Twenty-seven trials were eligible for inclusion. Clinically important pain relief differed significantly between short, intermediate, and long-term treatment durations (P = 0.05). Opioid recipients were more likely to be responders in short-term trials (8 trials, RR 1.42, 95% CI 1.08 to 1.89, moderate-certainty evidence), but not in intermediate-term trials (3 trials, RR 1.04, 95% CI 0.84 to 1.30, low-certainty evidence), nor long-term trials (9 trials, RR 0.91, 95% CI 0.73 to 1.14, moderate-certainty evidence), which trended in favour of controls. The mean difference in pain scores failed to reach our definition of clinical significance (≥10-points) for any time point, but was statistically significant in the short and intermediate-term. Conclusion Although opioids likely provide meaningful pain relief over short durations (≤4 weeks), they appear to provide little or no benefit beyond placebo over longer periods, and may worsen pain control beyond 12-weeks.
Froentjes et al. (Thu,) studied this question.