The smallest worthwhile effect on pain intensity of exercise therapy for people with chronic low back pain: a discrete choice experiment study.

OBJECTIVE: To identify the smallest worthwhile effect (SWE) of exercise therapy for people with non-specific chronic low back pain (CLBP). DESIGN: Discrete choice experiment. METHODS: The SWE was estimated as the lowest reduction in pain that participants would consider exercising worthwhile, compared to not exercising i.e., effects due to natural history and other components (e.g., regression to the mean). We recruited English-speaking adults in Australia with non-specific CLBP to our online survey via email obtained from a registry of previous participants and advertisements on social media. We used discrete choice experiment to estimate the SWE of exercise compared to no exercise for pain intensity. We analysed the discrete choice experiment using a mixed logit model, and mitigated hypothetical bias through certainty calibration, with sensitivity analyses performed with different certainty calibration thresholds. RESULTS: Two-hundred and thirteen participants completed the survey. The mean age (±SD) was 50.7±16.5, median (IQR) pain duration 10 years (5-20), and mean pain intensity (±SD) was 5.8±2.3 on a 0-10 numerical rating scale. For people with CLBP the SWE of exercise was a between-group reduction in pain of 20%, compared to no exercise. In the sensitivity analyses, the SWE varied with different levels of certainty calibration; from 0% without certainty calibration to 60% with more extreme certainty calibration. CONCLUSION: This patient-informed threshold of clinical importance could guide the interpretation of findings from randomised trials and meta-analyses of exercise therapy compared to no exercise.

Reporting of Observational Studies Explicitly Aiming to Emulate Randomized Trials: A Systematic Review.

Importance: Observational (nonexperimental) studies that aim to emulate a randomized trial (ie, the target trial) are increasingly informing medical and policy decision-making, but it is unclear how these studies are reported in the literature. Consistent reporting is essential for quality appraisal, evidence synthesis, and translation of evidence to policy and practice. Objective: To assess the reporting of observational studies that explicitly aimed to emulate a target trial. Evidence Review: We searched Medline, Embase, PsycINFO, and Web of Science for observational studies published between March 2012 and October 2022 that explicitly aimed to emulate a target trial of a health or medical intervention. Two reviewers double-screened and -extracted data on study characteristics, key predefined components of the target trial protocol and its emulation (eligibility criteria, treatment strategies, treatment assignment, outcome[s], follow-up, causal contrast[s], and analysis plan), and other items related to the target trial emulation. Findings: A total of 200 studies that explicitly aimed to emulate a target trial were included. These studies included 26 subfields of medicine, and 168 (84%) were published from January 2020 to October 2022. The aim to emulate a target trial was explicit in 70 study titles (35%). Forty-three studies (22%) reported use of a published reporting guideline (eg, Strengthening the Reporting of Observational Studies in Epidemiology). Eighty-five studies (43%) did not describe all key items of how the target trial was emulated and 113 (57%) did not describe the protocol of the target trial and its emulation. Conclusion and Relevance: In this systematic review of 200 studies that explicitly aimed to emulate a target trial, reporting of how the target trial was emulated was inconsistent. A reporting guideline for studies explicitly aiming to emulate a target trial may improve the reporting of the target trial protocols and other aspects of these emulation attempts.

The smallest worthwhile effect on pain intensity of nonsteroidal anti-inflammatory drugs and exercise therapy for acute and chronic low back pain: a benefit-harm trade-off study.

QUESTION: What are the smallest worthwhile effects of nonsteroidal anti-inflammatory drugs (NSAIDs) for people with acute and chronic low back pain (LBP)? What is the smallest worthwhile effect of individualised exercise for people with chronic LBP compared with no intervention? DESIGN: Benefit-harm trade-off study. PARTICIPANTS: Participants were recruited by advertisement on social media and included if they were English-speaking adults in Australia who had non-specific LBP. OUTCOME MEASURE: Pain intensity. RESULTS: A total of 116 people with acute LBP and 230 people with chronic LBP were recruited. For acute LBP, the smallest worthwhile effect of NSAIDs additional to no intervention was a 30% (IQR 10 to 40%) reduction in pain intensity. For chronic LBP, the smallest worthwhile effect of NSAIDs additional to no intervention was a 27.5% (IQR 10 to 50%) reduction in pain intensity. For chronic LBP, the smallest worthwhile effect of exercise additional to no intervention was a 20% (IQR 10 to 40%) reduction in pain intensity. There were small associations between baseline pain, duration of pain and level of exercise and the smallest worthwhile effect of NSAIDs for acute LBP. There were no other clear associations. CONCLUSIONS: For people with LBP, the smallest worthwhile effect of exercise and NSAIDs additional to no intervention is approximately a 20 to 30% reduction in pain. These results can inform the interpretation of the effects of NSAIDs and exercise in randomised trials and meta-analyses, incorporating consumers' perspectives. Further research on comparisons between different interventions and on other core LBP outcomes may inform decision-making. REGISTRATION: OSF osf.io/3erjx/.

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).