(P-319) Prevalence of Adverse Drug Reactions in the Primary Care Setting: A Systematic Review and Meta-analysis

Background: Adverse drug reactions (ADRs) represent a major cause of iatrogenic morbidity and mortality in patient care. While a substantial body of work had been undertaken to characterise ADRs in the hospital setting, there is little clarity on the overall burden of ADRs in the primary care, where the majority of medications are prescribed.

Objectives: To estimate the prevalence of ADRs in the primary care setting and factors affecting their heterogeneity.

Methods: Studies were identified through searching of Medline, Embase, CINAHL and IPA databases across all publication dates up to June 2020. We included observational studies that estimated the prevalence of ADRs in primary care. Disease and treatment specific studies were excluded. Quality of the included studies were assessed using Smyth ADRs adapted scale. A random-effects model was used to calculate the pooled estimate. Potential source of heterogeneity, including age groups, methods of ADRs detection, ADRs definitions, setting, quality of the studies, and sample size, were investigated using sub-group analysis and meta-regression.

Results: Twenty-seven studies with a total study population of 1,566,703 individuals were included in this study. The prevalence of ADRs in the primary care setting ranged from 0.43-34.70%, with the pooled prevalence of 6.74% (95% CI, 6.26, 7.22). Cardiovascular system drugs were the most commonly implicated medication class. The percentage of preventable ADRs in the primary care ranged from 12.35-37.96%, with the pooled estimate of 22.96 (95% CI, 7.82, 38.09). Methods of ADRs detection, age group, setting, and sample size contributed significantly to the heterogeneity of the estimates.

Conclusions: ADRs constitute a significant health problem in the primary care setting. Further research should focus on examining whether ADRs affect subsequent clinical outcomes, particularly in high-risk therapeutic areas. This information may better inform strategies to reduce the burden of ADRs in the primary care setting.