Background: Underreporting is the major limitation of a voluntary adverse drug reaction (ADR) reporting system. Many studies have assessed the effectiveness of different interventions designed to reduce underreporting.
Objective: We aimed to conduct a critical review of papers that assessed the effectiveness of different strategies to increase ADR reporting, regardless of the health professionals or patients included.
Data sources: Scientific papers were selected after a search of the MEDLINE-PubMed and EMBASE scientific databases up to 7 December 2010.
Study selection: We included papers in English, French or Spanish that analysed an intervention aimed at increasing the number of reported ADRs, and quantify the results of the intervention in terms of number of reports.
Data extraction: The abstracts retrieved in both computerized searches were reviewed independently by two of the authors. Initially selected papers were thoroughly read to evaluate if they met inclusion and exclusion criteria. Data in finally selected papers were independently extracted by both authors and set in pre-designed tables. A third author took the final decision in case of disagreement. For each study, we analysed study design, type of intervention, assessment period, and results of the intervention.
Results: Of the 4,221 papers located that fulfilled the search criteria, 43 met the selection criteria. With the exception of one study, the interventions assessed were deemed to be effective. The vast majority of papers displayed methodological and formal limitations that lowered the grade of evidence. Multiple interventions seem to have had more impact than did single interventions. There were very few cases in which interventions were designed on the basis of inappropriate attitudes and mistaken beliefs about ADRs.
Conclusions: In general, there is a need for studies of better methodological quality in this topic, so that more evidence of the effectiveness of the respective strategies can be collected for the purpose of improving ADR reporting by health professionals. It is probable that multiple interventions cause greater increases in the ADR reporting rates than single.