Prevalence and Determinants of Improper Pharmaceutical Disposal in Nigeria: A Systematic Review and Meta-Analysis

Background: Improper disposal of unused or expired pharmaceuticals poses significant environmental and public health risks, including antimicrobial resistance and water contamination. Despite growing concern, national-level estimates of improper disposal practices in Nigeria remain unavailable. Objective: To systematically synthesize the prevalence of improper drug disposal practices in Nigeria and identify key moderators of heterogeneity. Methods: We systematically searched electronic databases for studies reporting disposal practices among any population in Nigeria. A random-effects meta-analysis was performed to pool the prevalence of improper disposal (defined as discarding in solid waste, flushing, burning, or hoarding). Subgroup analyses, meta-regression, and sensitivity analyses were conducted to explore heterogeneity. Publication bias was assessed using Egger's test and trim-and-fill adjustment.