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Zinc acetate lozenges for treating the common cold: an individual patient data meta-analysis
Individual patient data meta-analysis of three double-blind placebo-controlled trials (199 cold patients): one-stage pooling estimated mean common cold duration 2.73 days shorter with zinc acetate lozenges versus placebo (95% CI 1.8–3.3 days); two-stage estimate 2.94 days (95% CI 2.1–3.8 days), with no meaningful modification by allergy status, smoking, baseline severity, age, sex, or ethnicity in the reported models.
Design
- IPD from three randomised, double-blind, placebo-controlled trials of zinc acetate lozenges in common cold patients
- Analytics: one-stage and two-stage IPD meta-analyses
Pooled cold-duration signals (abstract)
- One-stage model: 2.73 days shorter illness (95% CI 1.8–3.3)
- Two-stage model: 2.94 days shorter (95% CI 2.1–3.8)
- Context: authors compare with ~7-day mean cold duration in the constituent trials
- Subgroup stability: effects not materially modified by allergy, smoking, baseline severity, age, sex, or ethnicity in reported models
Evidence hygiene
- Zinc acetate lozenge formulation and dosing schedule matter—do not equate with multivitamins, intranasal zinc, or chronic preventive megadoses (taste, nausea, and copper-balance cautions appear in broader zinc literature).
Publication
Hemilä H, Petrus EJ, Fitzgerald JT, Prasad A. Br J Clin Pharmacol. 2016 Nov;82(5):1393-1398. PMID 27378206.
Outcomes
- Effect Size (Cohen's d / SMD)Common cold duration shortened by mean 2.73 days (95% CI 1.8–3.3) with zinc acetate lozenges versus placebo in one-stage IPD meta-analysis of three RCTs (n=199 patients; Hemilä et al. 2016).