Risk factors for the development of adverse drug events in hospitalized patients

Adverse drug events in hospitalized patients lead to increased morbidity, m ortality and costs. Early detection of adverse drug events could aid in the prevention of these adverse outcomes. A cost-effective system for the earl y detection of adverse drug events should focus on high risk patients. A st udy was set up with the primary aim to identify characteristics that are as sociated with the development of adverse drug events (ADEs) in hospitalized patients. ADE reports were gathered from physicians and nurses (spontaneou s reports) and from patients after intensive ward interviews by hospital ph armacists. All patients admitted to the internal medicine wards of two Dutc h hospitals, during a two month period, were included. The following characteristics were analyzed for their potential relationshi p to the occurence of ADEs: age (categorized), gender, number of drugs pres cribed during hospital stay, types of drugs used and changes in drug use on admission. Age was found to be inversely associated with the development o f ADEs (OR 0.36, CI 0.21-0.61 for age category > 80 years; OR 0.56; CI 0.31 -1.02 for age category 75-80 years and OR 0.69; CI 0.42-1.11 for age catego ry 60-74 years). Furthermore, statistically significant associations were f ound for the number of drugs prescribed per hospitalized patient (for the c lass of 4-6 drugs per patient OR 2.61, CI 1.32-5.18), for newly prescribed drugs (OR 6.65, CI 2.63-16.81) and for the cessation of drugs on hospital a dmission (OR 1.50, CI 1.02-2.20). The use of gastrointestinal drugs (OR 2.1 3, CI 1.32-3.45), central nervous system drugs (OR 1.66, CI 1.07-2.57) and antibiotics (OR 2.44, CI 1.65-3.60) were associated with the development of ADEs, when compared to all other drugs taken by the patients. In this study, the most important risk factors are the number of drugs used per patient and the starting of a new drug during hospitalization. As most hospitalized patients start new drug therapies while in hospital, this see ms an inappropriate focus. However, careful monitoring of patients using mo re than 7 drugs at a time may be possible in a cost-effective system for th e early detection of ADEs.