Prevalence of fatal adverse drug reactions in hospitalized patients

Objective: The aims of the present study were to assess the prevalence of fatal adverse drug reactions (FADRs) in a hospitalized population, identify the drugs Involved and investigate reported risk factors for these events. Methods: The study population of this retrospective, single-centre case study comprised 289 patients dying between 1 January 2004 and 31 December 2004 and registered in the Cause of Death Register of a teaching hospital. All compiled data were recorded by two observers especially trained to identify and report adverse drug reactions (ADRs). The degree of probability that the ADR led directly to death was determined by using WHO criteria and an adapted version of Naranjo's score. Results: Among 289 deceased study subjects, 17 (5.9%) were suspected to have died from an ADR. The most common suspected FADRs were gastrointestinal hemorrhages (52.9%), central nervous system hemorrhages (17.6%), cardiac disorders (17.6%), drug-induced myelosuppression (6%) and anti microbial-related enterocolitis (6%). The drugs most frequently implicated in a FADR were antithrombotic drugs (65%), nonsteroidal anti-inflammatory drugs (NSAIDs) (47%) and corticosteroids (29%). The only risk factors associated with FADRs in this population were multiple-drug therapy and the presence of platelet anti-aggregants and NSAIDs, alone or associated. Conclusions: FADRs are an important cause of death in hospitalized patients. Hemorrhages were seen in a majority of the fatal reactions, and antithrombotic agents or NSAIDs were implicated in most of these events.