Comparative effectiveness and safety of analgesic medicines for adults with non-specific acute low back pain: systematic review and network meta-analysis

Abstract

Objective To evaluate the comparative effectiveness and safety of analgesic medicines for acute non-specific low back pain. Design Systematic review and network meta-analysis. Data sources Medline, PubMed, Embase, CINAHL, CENTRAL, ClinicalTrials.gov, clinicialtrialsregister.eu, and World Health Organization’s International Clinical Trials Registry Platform from database inception to 20 February 2022. Eligibility criteria for study selection Randomised controlled trials of analgesic medicines (eg, non-steroidal anti-inflammatory drugs, paracetamol, opioids, anti-convulsant drugs, skeletal muscle relaxants, or corticosteroids) compared with another analgesic medicine, placebo, or no treatment. Adults (≥18 years) who reported acute non-specific low back pain (for less than six weeks). Data extraction and synthesis Primary outcomes were low back pain intensity (0-100 scale) at end of treatment and safety (number of participants who reported any adverse event during treatment). Secondary outcomes were low back specific function, serious adverse events, and discontinuation from treatment. Two reviewers independently identified studies, extracted data, and assessed risk of bias. A random effects network meta-analysis was done and confidence was evaluated by the Confidence in Network Meta-Analysis method. Results 98 randomised controlled trials (15 134 participants, 49% women) included 69 different medicines or combinations. Low or very low confidence was noted in evidence for reduced pain intensity after treatment with tolperisone (mean difference −26.1 (95% confidence intervals −34.0 to −18.2)), aceclofenac plus tizanidine (−26.1 (−38.5 to −13.6)), pregabalin (−24.7 (−34.6 to −14.7)), and 14 other medicines compared with placebo. Low or very low confidence was noted for no difference between the effects of several of these medicines. Increased adverse events had moderate to very low confidence with tramadol (risk ratio 2.6 (95% confidence interval 1.5 to 4.5)), paracetamol plus sustained release tramadol (2.4 (1.5 to 3.8)), baclofen (2.3 (1.5 to 3.4)), and paracetamol plus tramadol (2.1 (1.3 to 3.4)) compared with placebo. These medicines could increase the risk of adverse events compared with other medicines with moderate to low confidence. Moderate to low confidence was also noted for secondary outcomes and secondary analysis of medicine classes. Conclusions The comparative effectiveness and safety of analgesic medicines for acute non-specific low back pain are uncertain. Until higher quality randomised controlled trials of head-to-head comparisons are published, clinicians and patients are recommended to take a cautious approach to manage acute non-specific low back pain with analgesic medicines.MAW was supported by a Postgraduate Scholarship from the National Health and Medical Research Council of Australia, a School of Medical Sciences Top-Up Scholarship from the University of New South Wales, and a PhD Supplementary Scholarship from Neuroscience Research Australia. MKB was supported by a PhD Candidature Scholarship and Supplementary Scholarship from Neuroscience Research Australia. MCF was supported by an Australian Government Research Training Program Scholarship, a PhD Supplementary Scholarship from Neuroscience Research Australia, and the Edward C Dunn Foundation Scholarship. RRNR was supported by the School of Medical Sciences Postgraduate Research Scholarship from the University of New South Wales and a PhD Supplementary Scholarship from Neuroscience Research Australia. HBL was supported by an Australian Government Research Training Program Scholarship. SSh was supported by the International Association for the Study of Pain John J Bonica Postdoctoral Fellowship. CGM was supported by an NHMRC Leadership 3 Fellowship (App 1194283). SMG was supported by a Research Fellowship from the Rebecca L Cooper Foundation. AN was supported by personal fellowship (P400PM_186723) from the Swiss National Science Foundation. This study received project support funding from a 2020 Exercise Physiology Research (Consumables) Grant from the University of New South Wales, which was used to obtain translations of studies published in languages other than English. The funder had played no part in the design, conduct, or analysis of the study