Cohort study on Adverse Drug Reactions in adults admitted to the medical wards of a tertiary hospital in Nigeria: Prevalence, incidence, risk factors and fatality.

Adedapo, Aduragbenro D A; Adedeji, Waheed A; Adedapo, Ifetoluwanimi A; Adedapo, Kayode S

AIMS Intensive monitoring of medical patients for ADRs to assess prevalence, incidence, risk factors and fatality of ADRs leading to hospital admission or occurring in the hospital. Research design and methods Prospective cohort study on 1280 adult patients admitted to the medical wards of a tertiary institution over 12 months. Patients were assessed for ADRs during and throughout admission; causality and preventability of ADRs were assessed. RESULTS Sixty-seven (5.2%) patients had ADRs, 51(3.9%) caused hospitalisation while 17(1.3%) occurred during hospitalisation, and 42(62.7%) of total ADRs were preventable. NSAIDs, 14 (20.3%), antidiabetics, 12 (17.4%) and antibacterial, 11 (15.8%) were the most implicated drug classes. Gastrointestinal tract (37%), CNS (30.2%), and skin (24.7%) were the most affected organ/systems, while upper GI bleeding and hypoglycaemia were the most observed ADRs. ADRs led to deaths in 7(10.4%) patients, with an overall case fatality rate of 0.5%. The highest number of deaths were among patients with Stevens-Johnson Syndrome 2/7(28.6%) and hepatotoxicity 2/7(28.6%). Risk factors, AOR (95% CI) for ADRs leading to hospitalisation was male gender 3.11 (1.11, 8.73) while for ADRs during hospitalisation were number of drugs used before admission [AOR (95% CI) = 6.67(1.16, 38.47] and comorbidities [AOR (95% CI) = 3.0 (1.13, 8.01)]. Patients admitted with ADRs had prolonged hospital stay [AOR (95% CI) = 3.37(1.11, 8.71)]. CONCLUSIONS Preventable ADRs are common and important causes of hospitalisation and inpatients' morbidity and mortality among medical patients in Nigeria. Upper GI bleeding and hypoglycaemia, resulting from NSAIDs and antidiabetic drugs were the most observed ADRs.