Adverse drug reactions in elderly patients following discharge from an internal medicine clinic.

Objective: The aim of this study was to evaluate the incidence and type of adverse drug reactions (ADRs) and identify risk factors for ADRs in elderly patients within 30 days following discharge from an internal medicine clinic.

Methods: A prospective observational study was conducted at the Internal Medicine Clinic of University Hospital Dubrava, Zagreb, Croatia, between September 1(st) and November 30(th) 2012. Patients aged ≥ 65 years discharged from the clinic during the study period were eligible for inclusion in the study. The follow-up visit was scheduled ~ 30 days after discharge. During the visit, the patients were assessed for the occurrence of ADRs. Two independent physicians evaluated each possible ADR by using the Naranjo ADR probability scale. Multivariate logistic regression analysis was used to identify predisposing factors for ADRs.

Results: There were 209 patients included in this study. A total of 72 ADRs were detected in 63 (30.1%) patients. The most frequent ADRs were bleeding disorders associated with warfarin therapy, followed by hypoglycemia associated with antidiabetics. Five (6.9%) ADRs, which resulted in hospital admission, were classified as serious. Multivariate logistic regression analysis indicated number of prescribed drugs ≥4 and prescription of furosemide and warfarin to be associated with increased risk of ADRs.

Conclusions: Our study showed that ADRs are an important cause of morbidity in elderly patients after hospital discharge. Judicious prescription of drugs and careful and frequent monitoring of drug therapy are necessary to reduce the risk of ADRs.