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Abstract
Placebo response variability in neuropathic pain trials complicates indirect comparisons of pharmacotherapies. This meta-regression analysis of 39 randomized placebo-controlled trials identified predictors of placebo response and treatment effect after adjustment for placebo. Key predictors included dosing flexibility, baseline pain, gender distribution, and diagnosis of painful diabetic neuropathy. After controlling for placebo response, longer treatment duration was inversely associated with treatment effect and explained most between-study variance in sensitivity analyses. Findings highlight the need for standardized trial designs and consideration of placebo-related factors in systematic reviews and meta-analyses to improve interpretation and generalizability of neuropathic pain treatment evidence.