Patient versus healthcare professional spontaneous adverse drug reaction reporting: a systematic review.

BACKGROUND: Increasing numbers of national pharmacovigilance schemes are accepting adverse drug reaction (ADR) reports from patients. The extent to which patient ADR reports contribute to pharmacovigilance requires comparisons to be made with reports from healthcare professionals (HCPs).
OBJECTIVE: This systematic review was conducted to identify all comparative studies of patient and HCP ADR reports to national pharmacovigilance schemes.
METHODS: We conducted a systematic review (which complied with the PRISMA statement) and a narrative synthesis of the results. Electronic databases (1996-2011) were searched, including MEDLINE, EMBASE and PHARM-Line, and supplementary searching of reference lists of included studies, authors' personal reference lists and internet searches was carried out. Studies that compared patient and HCP ADR reports submitted to national reporting schemes were considered for inclusion. Independent, duplicate data extraction, quality assessment and risk of bias were undertaken.
RESULTS: Of the 949 hits generated, three comparative studies were identified and included in this review. These studies were conducted on the national pharmacovigilance schemes in the Netherlands, Denmark and the UK. Considerable variation was observed across the national schemes in terms of the proportion of total ADR reports submitted by patients. Some of this variation may be explained by the duration that the schemes have been in operation. The number of serious ADR reports as a percentage of total reports was similar for patients compared with HCPs within each study, but varied across studies. Similarities were shown with the Netherlands and the UK in terms of drugs reported. Both studies featured statins and proton pump inhibitors in the top five drugs. Clear differences were shown between patients and HCPs in the body systems affected by ADRs as well as the therapeutic categories reported in both the UK and Danish studies. There was considerable similarity when considering the nature of ADRs reported. The Dutch study also showed similarities between patients and physicians in terms of the types of drugs for which ADRs were reported.
CONCLUSIONS: Despite the large and increasing number of national pharmacovigilance schemes that accept ADR reports from patients, few comparative studies have been undertaken of patient and HCP reporting. Comparison across schemes is challenging because of differences in reporting processes, the inclusion criteria of schemes and different reporter types. The true value of patient ADR reports to pharmacovigilance will remain unknown unless more comparative evaluations are undertaken. This systematic review has highlighted both similarities and differences between reporter behaviour, the implications of which, in terms of signal generation, require further exploration.