Interventions to reduce opioid use for patients with chronic non-cancer pain in primary care settings: A systematic review and meta-analysis

Objective: This systematic review and meta-analysis aimed to assess interventions to reduce opioid use for patients with chronic non-cancer pain (CNCP) versus usual care or active controls in primary care settings. Methods: In this registered study (PROSPERO: CRD42022338458), we searched MEDLINE, Embase PsycInfo, CINAHL, and Cochrane Library from inception to December 28th 2021, and updated on Dec 14th 2023 for randomized controlled trials (RCTs) and cohort studies with no restrictions. Methodological quality was assessed using the Cochrane Risk of Bias tool for RCTs and Newcastle Ottawa Scale for cohort studies. Primary outcomes included mean reduction in morphine equivalent daily dose (reported as mean differences [MDs] mg/day; 95% confidence intervals [95%CIs]) and/or opioid cessation proportion. Secondary outcomes were mean changes in pain severity (reported as standardized mean difference [SMDs]; 95%CIs) and (serious) adverse events. Meta-analyses were performed using random-effects models. Results: We identified 3,826 records, of which five RCTs (953 participants) and five cohort studies (901 participants) were included. Overall, opioid dosage was significantly reduced in intervention groups compared to controls (MD: -28.63 mg/day, 95%CI: -39.77 to -17.49; I2 = 31.25%; eight studies). Subgroup analyses revealed significant opioid dose reductions with mindfulness (MD: -29.36 mg/day 95%CI: -40.55 to -18.17; I2 = 0.00%; two trials) and CBT-based multimodalities (MD: -41.68 mg/day; 95%CI: -58.47 to -24.89; I2 = 0.00%; two cohort studies), respectively, compared to usual care. No significant differences were observed in opioid cessation (Odds ratio: 1.10, 95%CI: -0.48 to 2.67, I2 = 58.59%; two trials) or pain severity (SMD: -0.13, 95%CI: -0.37 to 0.11; I2 = 33.51%; three trials). Adverse events were infrequently examined, with withdrawal symptoms commonly reported. Conclusions: The studied interventions were effective in reducing opioid dosage for people with CNCP in primary care. They highlighted the importance of multidisciplinary collaboration. Large-scale RCTs measuring the long-term effects and cost of these interventions are needed before their implementation.