Analgesic medicines for adults with low back pain: protocol for a systematic review and network meta-analysis

Pharmacological treatments for low back pain in adults: an overview of Cochrane Reviews

BACKGROUND

Pharmacological interventions are the most used treatment for low back pain (LBP). Use of evidence from systematic reviews of the effects of pharmacological interventions for LBP published in the Cochrane Library, is limited by lack of a comprehensive overview.

OBJECTIVES

To summarise the evidence from Cochrane Reviews of the efficacy, effectiveness, and safety of systemic pharmacological interventions for adults with non-specific LBP.

METHODS

The Cochrane Database of Systematic Reviews was searched from inception to 3 June 2021, to identify reviews of randomised controlled trials (RCTs) that investigated systemic pharmacological interventions for adults with non-specific LBP. Two authors independently assessed eligibility, extracted data, and assessed the quality of the reviews and certainty of the evidence using the AMSTAR 2 and GRADE tools. The review focused on placebo comparisons and the main outcomes were pain intensity, function, and safety.

MAIN RESULTS

Seven Cochrane Reviews that included 103 studies (22,238 participants) were included. There is high confidence in the findings of five reviews, moderate confidence in one, and low confidence in the findings of another. The reviews reported data on six medicines or medicine classes: paracetamol, non-steroidal anti-inflammatory drugs (NSAIDs), muscle relaxants, benzodiazepines, opioids, and antidepressants. Three reviews included participants with acute or sub-acute LBP and five reviews included participants with chronic LBP. Acute LBP Paracetamol There was high-certainty evidence for no evidence of difference between paracetamol and placebo for reducing pain intensity (MD 0.49 on a 0 to 100 scale (higher scores indicate worse pain), 95% CI -1.99 to 2.97), reducing disability (MD 0.05 on a 0 to 24 scale (higher scores indicate worse disability), 95% CI -0.50 to 0.60), and increasing the risk of adverse events (RR 1.07, 95% CI 0.86 to 1.33). NSAIDs There was moderate-certainty evidence for a small between-group difference favouring NSAIDs compared to placebo at reducing pain intensity (MD -7.29 on a 0 to 100 scale (higher scores indicate worse pain), 95% CI -10.98 to -3.61), high-certainty evidence for a small between-group difference for reducing disability (MD -2.02 on a 0-24 scale (higher scores indicate worse disability), 95% CI -2.89 to -1.15), and very low-certainty evidence for no evidence of an increased risk of adverse events (RR 0.86, 95% CI 0. 63 to 1.18). Muscle relaxants and benzodiazepines There was moderate-certainty evidence for a small between-group difference favouring muscle relaxants compared to placebo for a higher chance of pain relief (RR 0.58, 95% CI 0.45 to 0.76), and higher chance of improving physical function (RR 0.55, 95% CI 0.40 to 0.77), and increased risk of adverse events (RR 1.50, 95% CI 1. 14 to 1.98). Opioids None of the included Cochrane Reviews aimed to identify evidence for acute LBP. Antidepressants No evidence was identified by the included reviews for acute LBP. Chronic LBP Paracetamol No evidence was identified by the included reviews for chronic LBP. NSAIDs There was low-certainty evidence for a small between-group difference favouring NSAIDs compared to placebo for reducing pain intensity (MD -6.97 on a 0 to 100 scale (higher scores indicate worse pain), 95% CI -10.74 to -3.19), reducing disability (MD -0.85 on a 0-24 scale (higher scores indicate worse disability), 95% CI -1.30 to -0.40), and no evidence of an increased risk of adverse events (RR 1.04, 95% CI -0.92 to 1.17), all at intermediate-term follow-up (> 3 months and ≤ 12 months postintervention). Muscle relaxants and benzodiazepines There was low-certainty evidence for a small between-group difference favouring benzodiazepines compared to placebo for a higher chance of pain relief (RR 0.71, 95% CI 0.54 to 0.93), and low-certainty evidence for no evidence of difference between muscle relaxants and placebo in the risk of adverse events (RR 1.02, 95% CI 0.67 to 1.57). Opioids There was high-certainty evidence for a small between-group difference favouring tapentadol compared to placebo at reducing pain intensity (MD -8.00 on a 0 to 100 scale (higher scores indicate worse pain), 95% CI -1.22 to -0.38), moderate-certainty evidence for a small between-group difference favouring strong opioids for reducing pain intensity (SMD -0.43, 95% CI -0.52 to -0.33), low-certainty evidence for a medium between-group difference favouring tramadol for reducing pain intensity (SMD -0.55, 95% CI -0.66 to -0.44) and very low-certainty evidence for a small between-group difference favouring buprenorphine for reducing pain intensity (SMD -0.41, 95% CI -0.57 to -0.26). There was moderate-certainty evidence for a small between-group difference favouring strong opioids compared to placebo for reducing disability (SMD -0.26, 95% CI -0.37 to -0.15), moderate-certainty evidence for a small between-group difference favouring tramadol for reducing disability (SMD -0.18, 95% CI -0.29 to -0.07), and low-certainty evidence for a small between-group difference favouring buprenorphine for reducing disability (SMD -0.14, 95% CI -0.53 to -0.25). There was low-certainty evidence for a small between-group difference for an increased risk of adverse events for opioids (all types) compared to placebo; nausea (RD 0.10, 95% CI 0.07 to 0.14), headaches (RD 0.03, 95% CI 0.01 to 0.05), constipation (RD 0.07, 95% CI 0.04 to 0.11), and dizziness (RD 0.08, 95% CI 0.05 to 0.11). Antidepressants There was low-certainty evidence for no evidence of difference for antidepressants (all types) compared to placebo for reducing pain intensity (SMD -0.04, 95% CI -0.25 to 0.17) and reducing disability (SMD -0.06, 95% CI -0.40 to 0.29).

AUTHORS' CONCLUSIONS

We found no high- or moderate-certainty evidence that any investigated pharmacological intervention provided a large or medium effect on pain intensity for acute or chronic LBP compared to placebo. For acute LBP, we found moderate-certainty evidence that NSAIDs and muscle relaxants may provide a small effect on pain, and high-certainty evidence for no evidence of difference between paracetamol and placebo. For safety, we found very low- and high-certainty evidence for no evidence of difference with NSAIDs and paracetamol compared to placebo for the risk of adverse events, and moderate-certainty evidence that muscle relaxants may increase the risk of adverse events. For chronic LBP, we found low-certainty evidence that NSAIDs and very low- to high-certainty evidence that opioids may provide a small effect on pain. For safety, we found low-certainty evidence for no evidence of difference between NSAIDs and placebo for the risk of adverse events, and low-certainty evidence that opioids may increase the risk of adverse events.

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

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.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42019145257.

Rescaling pain intensity measures for meta-analyses of analgesic medicines for low back pain appears justified: an empirical examination from randomised trials

Objective

Meta-analyses of analgesic medicines for low back pain often rescale measures of pain intensity to use mean difference (MD) instead of standardised mean difference for pooled estimates. Although this improves clinical interpretability, it is not clear whether this method is justified. Our study evaluated the justification for this method.

Methods

We identified randomised clinical trials of analgesic medicines for adults with low back pain that used two scales with different ranges to measure the same construct of pain intensity. We transformed all data to a 0–100 scale, then compared between-group estimates across pairs of scales with different ranges.

Results

Twelve trials were included. Overall, differences in means between pain intensity measures that were rescaled to a common 0–100 scale appeared to be small and randomly distributed. For one study that measured pain intensity on a 0–100 scale and a 0–10 scale; when rescaled to 0–100, the difference in MD between the scales was 0.8 points out of 100. For three studies that measured pain intensity on a 0–10 scale and 0–3 scale; when rescaled to 0–100, the average difference in MD between the scales was 0.2 points out of 100 (range 5.5 points lower to 2.7 points higher). For two studies that measured pain intensity on a 0–100 scale and a 0–3 scale; when rescaled to 0–100, the average difference in MD between the scales was 0.7 points out of 100 (range 6.2 points lower to 12.1 points higher). Finally, for six studies that measured pain intensity on a 0–100 scale and a 0–4 scale; when rescaled to 0–100, the average difference in MD between the scales was 0.7 points (range 5.4 points lower to 8.3 points higher).

Conclusion

Rescaling pain intensity measures may be justified in meta-analyses of analgesic medicines for low back pain. Systematic reviewers may consider this method to improve clinical interpretability and enable more data to be included.

Study registration/data availability

Open Science Framework (osf.io/8rq7f).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12874-022-01763-x.

The Effect and Safety of Thunder-Fire Moxibustion for Low Back Pain: A Meta-Analysis of Randomized Controlled Trials

Background

Low back pain (LBP) is considered the leading cause of people living with years of disability worldwide. Notably, thunder-fire moxibustion (TFM) is a new type of moxibustion, which has been widely applied to treat pain syndromes for thousands of years. This study aims to provide evidence to evaluate the effect and safety of TFM in treating LBP.

Methods

A systematic search of PubMed, Web of Science, the Cochrane Library, Embase, EBSCO, CNKI, Wanfang Data, CBM, and VIP (until April 2021) was used to identify studies reporting pain intensity, disability, Japanese Orthopedic Association (JOA) score, and quality of life in patients with LBP. Randomized controlled trials (RCTs), which compared TFM and other therapies in LBP, were included. Meanwhile, methodological quality was evaluated using the Cochrane criteria for risk of bias, and the level of evidence was rated utilizing the GRADE approach.

Results

Twenty-one RCTs, including 2198 patients, satisfied the inclusion criteria. Compared with other therapies, the effect of TFM was statistically significant, pain intensity decreased (SMD = 0.94; 95% CI (0.74, 1.14); p < 0.00001), disability improved (SMD = 1.39; 95% CI (0.19, 2.59); p=0.02), and the JOA score increased (SMD = -1.34; 95% CI (-1.88, -0.80); p < 0.00001). It was also reported that the patient's quality of life improved after treatment for a period of 4 weeks (SMD = -0.29; 95% CI (-0.42, -0.16); p < 0.0001) and after a follow-up of 1 month (SMD = -0.20; 95% CI (-0.34, -0.07); p=0.003). The evidence level of the results was determined to be very low to low.

Conclusions

Based on the existing evidence, it can be concluded that TFM may have a better effect than other treatments on LBP. However, it is not yet possible to assess the safety level of TFM therapy. Due to the universal low quality of the eligible trials and low evidence level, rigorously designed large-scale RCTs must be conducted in order to further confirm the results in this review.