Articles: pain-clinics.
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Little is known about the contribution of placebo effects and changes observed with no treatment in interventions for nonspecific low back pain (NSLBP). This systematic review assessed the proportions of the overall treatment effect that may be attributable to specific treatment effects, placebo effects, and changes observed with no treatment in randomized controlled trials (RCTs) in patients with NSLBP. Trials published before 2019 were identified from a published systematic review, and the search was updated in MEDLINE, Embase, and Cochrane Central for trials published between January 2019 and March 2023. ⋯ For physical function (11 studies) and HRQoL (6 studies), these proportions were 34%, 13%, and 53%, and 11%, 41%, and 48%, respectively. These results show that approximately half of the overall treatment effect of conservative and mainly passive interventions for patients with chronic NSLBP is attributable to changes observed with no treatment, rather than specific or placebo effects of treatments. However, the certainty of evidence was very low to low, suggesting that the true effects might be markedly different from the effect sizes underlying these estimates.
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Recent literature suggests that the withdrawal of remifentanil (RF) infusion can be associated with hyperalgesia in clinical and nonclinical settings. We performed a systematic review and a meta-analysis of randomized controlled trials with cross-over design, to assess the effect of discontinuing RF infusion on pain intensity and areas of hyperalgesia and allodynia in healthy volunteers. Nine studies were included. ⋯ The area of hyperalgesia was larger after RF withdrawal (SMD: 0.55; 95% CI: 0.27-0.84; P = 0.001; I 2 = 0%). The area of allodynia did not vary between treatments. These findings suggest that the withdrawal of RF induces a mild but nonclinically relevant degree of hyperalgesia in HVs, likely linked to a reduced pain threshold.
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Review Meta Analysis
The importance of context (placebo effects) in conservative interventions for musculoskeletal pain: A systematic review and meta-analysis of randomized controlled trials.
Contextual effects (e.g. patient expectations) may play a role in treatment effectiveness. This study aimed to estimate the magnitude of contextual effects for conservative, non-pharmacological interventions for musculoskeletal pain conditions. A systematic review and meta-analysis of randomized controlled trials (RCTs) that compared placebo conservative non-pharmacological interventions to no treatment for musculoskeletal pain. The outcomes assessed included pain intensity, physical functioning, health-related quality of life, global rating of change, depression, anxiety and sleep at immediate, short-, medium- and/or long-term follow-up. ⋯ Contextual effects of non-pharmacological conservative interventions for musculoskeletal conditions are likely to be small for a broad range of patient-reported outcomes (pain intensity, physical function, quality of life, global rating of change and depression). Contextual effects are unlikely, in isolation, to offer much clinical care. But these factors do have relevance in an overall treatment context as they provide almost 30% of the minimally clinically important difference.
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Review Meta Analysis
Placebo analgesia in physical and psychological interventions: Systematic review and meta-analysis of three-armed trials.
The magnitude of placebo effects from physical and psychological 'sham' is unknown but could impact efficacy trials and treatment understanding. To quantify placebo effects, this systematic review of three-armed randomised controlled trials (RCTs) of physical and psychological interventions for pain compared outcomes in 'sham' control intervention and non-exposure arms. ⋯ This systematic review directly quantifies placebo effects from physical and psychological 'sham' control interventions and compares them to treatments' overall effectiveness. By doing so, the review enhances our understanding of placebo effects, their relative contribution in clinical trials, and their susceptibly to trial design. It poses further questions regarding the influence of blinding, participant expectations, and features of the therapeutic context. Overall, the insights provided by this review carry methodological significance and are important for the interpretation and synthesis of efficacy trials in this field.
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Meta Analysis
The effect of experimental emotion induction on experimental pain: a systematic review and meta-analysis.
The idea that emotions can influence pain is generally recognized. However, a synthesis of the numerous individual experimental studies on this subject is lacking. The aim of the present systematic review and meta-analysis was to synthesize the existing evidence on the effect of experimental emotion induction on experimental pain in nonclinical adults. ⋯ Taken together, the findings indicate a pain-attenuating effect of positive emotion induction, while the findings for negative emotion induction are less clear. The findings are discussed with reference to theoretical work emphasizing the role of motivational systems and distraction for pain. Limitations include considerable heterogeneity across studies limiting the generalizability of the findings.