Effectiveness of placebo interventions for patients with nonspecific low back pain: a systematic review and meta-analysis

PainSci » bibliography » Strijkers et al 2021
updated Apr 7, 2023

Tags: mind

Two pages on PainSci cite Strijkers 2021: 1. Placebo Power Hype 2. Placebo enthusiasm cannot be curbed

PainSci notes on Strijkers 2021:

Strijkers et al. reviewed the magnitude of the placebo effect in trials comparing some kind of placebo with no treatment at all (for chronic unexplained back pain). They found 21 such trials, pooled the data, crunched the numbers… and found that the placebos did do more than doing nothing, a literally better-than-nothing result. But only just BARELY better than nothing: “probably not clinically relevant.” Less than 1 point on a 10-point pain scale! Scarcely noticeable.

(And some of that difference can almost certainly be attributed to research artifacts… not the mind asserting itself over pain.)

Such results are typical of the literature on placebo power.

original abstract †Abstracts here may not perfectly match originals, for a variety of technical and practical reasons. Some abstacts are truncated for my purposes here, if they are particularly long-winded and unhelpful. I occasionally add clarifying notes. And I make some minor corrections.

Little is known about the effectiveness of placebo interventions in patients with nonspecific low back pain (LBP). This systematic review assessed the magnitude of the effects of placebo interventions as compared to no intervention in randomized controlled trials (RCTs) including patients with LBP. Embase, MEDLINE (Ovid), and Cochrane CENTRAL databases were searched from inception to December 5, 2019. Randomized controlled trials comparing placebo intervention vs no intervention in adult patients with nonspecific LBP were included. Pain intensity, physical functioning, and health-related quality of life measured at short-term, medium-term, and long-term follow-up were the outcomes of this review. Twenty-one randomized controlled trials were included; one concerning acute LBP and one subacute LBP, whereas 19 studies reported on chronic LBP. In chronic LBP, placebo interventions were more effective than no intervention at short-term follow-up for pain intensity (standardized mean difference = -0.37, 95% confidence interval [CI] = -0.55 to -0.18, moderate-quality evidence), physical functioning (standardized mean difference -0.19, 95% CI = -0.39-0.01, moderate-quality evidence), and physical quality of life (mean difference = -2.71, 95% CI = -4.71-0.71, high-quality evidence), respectively. These effects were not significant at medium-term follow-up, and no data were available at long-term follow-up. These results show placebo interventions are more effective than no intervention at short-term follow-up in patients with chronic LBP. However, the magnitude of the effects is probably not clinically relevant (approximately 8 points on a 0-100 pain scale). Future research should identify effect modifiers and causal mechanisms explaining the short-term effects of placebo interventions in patients with chronic LBP.

original abstract †Abstracts here may not perfectly match originals, for a variety of technical and practical reasons. Some abstacts are truncated for my purposes here, if they are particularly long-winded and unhelpful. I occasionally add clarifying notes. And I make some minor corrections.

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