Epidemiology of adverse drug reactions in Europe: a review of recent observational studies

Abstract

Adverse drug reactions (ADRs) cause considerable mortality and morbidity but no recent reviews are currently available for the European region. Therefore, we performed a review of all epidemiological studies quantifying ADRs in a European setting that were published between 1 January 2000 and 3 September 2014. Included studies assessed the number of patients who were admitted to hospital due to an ADR, studies that assessed the number of patients who developed an ADR during hospitalization, and studies that measured ADRs in the outpatient setting. In total, 47 articles were included in the final review. The median percentage of hospital admissions due to an ADR was 3.5 %, based on 22 studies, and the median percentage of patients who experienced an ADR during hospitalization was 10.1 %, based on 13 studies. Only five studies were found that assessed ADRs occurring in the outpatient setting. These results indicate that the occurrence of ADRs in the European hospital setting-both ADRs that result in hospitalization and ADRs that occur during the hospital stay-is significant. Furthermore, the limited number of studies that were performed in the outpatient setting identify a lack of information regarding the epidemiology of ADRs in this setting.

Fig. 1

Different settings in which ADRs can occur and, when combined, make up the total morbidity and mortality resulting from ADRs in the hospital and outpatient settings. ADRs adverse drug reactions

Fig. 2

Selection process of all studies included in the review. In total, these articles resulted in 22 ADR occurrence rates at hospital admission, 32 ADR occurrence rates during hospitalization, and six ADR occurrence rates in other settings. ADR adverse drug reaction

Fig. 3

Variation in the reported percentage of hospital admissions caused by ADRs (all studies in unselected patient populations). Graph shows all studies that reported the percentage of hospital admissions caused by ADRs in various settings, excluding those studies that focused on children or the elderly. The median of these studies was 3.6 % and the mean was 4.6 % of all admissions. Light bars indicate that the study used ADEs/DRPs instead of ADRs. ADRs adverse drug reactions, ADE adverse drug event, DRP drug-related problem

Fig. 4

Variation in the reported percentage of in-hospital ADRs (all studies in unselected patient populations). Graph shows all studies that reported the percentage of patients who experienced an ADR during their hospital stay, and which were performed in various settings, excluding those studies that focused on children or the elderly. The median of all studies was 11.9 % and the mean was 22.0 % of all hospitalizations. When the study of Blix et al. [41] was excluded, the median was 10.1 % and the mean was 17.0 % of all hospitalizations. Light bars indicate that ADEs/DRPs were reported instead of ADRs. ADR adverse drug reaction, ADE adverse drug event, DRP drug-related problem