Economic burden, impact, and consequence of adverse drug reactions among medical inpatients in clinical practice

Abstract

Background: An adverse drug reaction (ADR) is defined in this study as a response to a drug which is noxious and unintended that occurs at doses normally used for therapeutic purposes. Despite the extensive study and attention given to ADRs, they still represent a clinically significant problem and burden with high prevalence. Aim: The main aim of this study was to adequately evaluate the economic burden, impact, and consequence of ADRs among adult medical inpatients in clinical practice, to highlight the pattern of medications most frequently involved in ADRs, and to estimate the economic cost implication of treating ADRs in such clinical practice setting. Methods: The patients admitted into the adult medical wards of a Nigerian university teaching hospital 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 male and 238 (46.9%) were female. The mean age of the study population was 48.9 ± 17.8 years (median: 46 years). Most ADRs were mild and moderate in 21 (41.2%) cases and 24 (47.1%) cases, respectively. Severe ADRs occurred in 2 (3.9%) cases, while four (7.8%) cases were fatal ADRs. The economic cost implication of treating ADRs was ₦ 161,668.00 ($1243.60), equivalent to about 1.9% of the total cost of all medications used by all admitted medical inpatients during admission. The cost of treating ADRs per patient with ADRs was ₦ 3169.96 ± ₦ 6348.77 ($24.38 ± $48.84), while the mean ADR treatment cost per admitted medical inpatient was ₦ 318.87 ($2.45). The most frequently affected body systems by ADRs were the central nervous system and the gastrointestinal system corresponding to the antidiabetic drug – insulin use causing neuroglycopenic symptoms and nonsteroidal anti-inflammatory drugs (NSAIDs) use causing NSAID-induced gastroenteritis/GIT bleeding, respectively. Conclusions: The economic burden, impact, and consequence of ADRs were significantly high among these adult medical inpatients. In this study, ADRs increase patients' morbidity, mortality, cost of health care, and length (duration) of hospitalization. Insulin and NSAIDs caused the highest number of ADRs which indicate that adequate caution, proper care, and continuous monitoring must be implemented during the course of treating patients with these drugs to optimize their clinical efficacy and prevent the occurrence of ADRs in them.