The incidence and prevalence of adverse drug reactions among medical inpatients in a Nigerian University Teaching Hospital

Abstract

Aim: Evaluating the incidence, prevalence, and pattern of adverse drug reactions (ADRs) with the extent to which they influence cost of healthcare is often informative and useful in patients' management, policymaking and safety considerations. Methods: The patients admitted into the internal medicine wards of a university teaching hospital, South-South Nigeria over a 9-month period from December 2013 to August 2014 were prospectively recruited for the study and followed up till discharge. Results: Five hundred and seven patients were evaluated during the study, out of which 269 (53.1%) of them were males and 238 (46.9%) were females. The mean age of the study population was 48.9 ± 17.8 years (median of 46 years). ADRs had an incidence of 6.5%, while its prevalence rate was 10.1%. The cost of treating ADR was ₦ 161668.00 ($1243.60), equivalent to 1.9% of the total cost of all medications used by patients during admission. The case fatality rate for ADRs was 7.8%, while ADR-related mortality rate was 0.8%. The most frequently affected body systems were the central nervous system and the gastrointestinal system corresponding to insulin use (causing neuroglycopenic symptoms) and nonsteroidal anti-inflammatory drugs (NSAIDs) use (causing NSAID-induced gastroenteritis/GIT bleeding) respectively. Conclusions: The incidence and prevalence of ADRs were clinically significant among these medical inpatients. In this study, ADRs increase patients morbidity, mortality, cost of health care, and duration of hospital stay as it has been shown by previous studies. Insulin caused the highest number of ADRs, suggesting the need for individual diabetic patients to acquire and learn the appropriate regular use of glucometers.