Improving the reporting of adverse drug reactions: a cluster-randomized trial among pharmacists in Portugal

Adverse drug reaction (ADR) reporting systems are the basic component for comprehensive postmarketing surveillance of the risk of drug-induced adverse effects. The aim of this study was to evaluate the effectiveness of educational outreach visits aimed at improving ADR reporting by pharmacists.

The study population comprised all pharmacists working in a catchment area covered by Portugal's Northern Regional Health Authority. Using unequal randomization, four spatial-clusters were assigned to the intervention group (n = 342) and eleven to the control group (n = 1091). The intervention took the form of 1-hour long educational outreach visits tailored to training needs detected in a previous study, with a 13- to 16-month follow-up period (March-June 2004 through June 2005). This study is registered as an international standard randomized controlled trial, number ISRCTN45894687.

At baseline, ADR reporting rates (per 1000 pharmacist-years) did not differ significantly between the intervention and control groups (32.28 vs 29.16). The adjusted increase in ADR reporting attributable to the intervention was 275.63 per 1000 pharmacist-years (95% CI 162.15, 389.12; relative risk [RR] = 5.87, 95% CI 1.98, 17.39). The intervention succeeded in multiplying the reporting rate of: serious ADRs, 10-fold (RR = 9.79; 95% CI 2.24, 42.66); unexpected ADRs, 4-fold (RR = 4.41; 95% CI 1.11, 17.53); high-causality ADRs, 9-fold (RR = 8.67; 95% CI 2.12, 35.42); and new drug-related ADRs, 9-fold (RR = 9.33; 95% CI 2.53, 34.40). While the greatest effect was registered during the first 4 months post-intervention, differences remained statistically significant for 8 months.

Educational outreach visits improve ADR reporting by pharmacists in terms of quantity and relevance.