Adverse drug reactions in adult medical inpatients in a South African hospital serving a community with a high HIV/AIDS prevalence: prospective observational study

UNLABELLED: What is already known about this subject. Studies conducted primarily in developed countries have shown that adverse drug reactions (ADRs) are a significant cause of hospital admission, prolong hospital stay and consequently increase the cost of disease management in patients. Cardiovascular medicines, hypoglycaemic agents, nonsteroidal anti-inflammatory drugs and antibiotics are the most frequently implicated medicines in these studies. A large proportion of these ADRs have been shown to be preventable through improved drug prescribing, administration and monitoring for adverse effects. What this paper adds. This is the first Sub-Saharan African study in the HIV/AIDS era that describes the contribution of ADRs to patient morbidity, hospitalisation and mortality. Cardiovascular medicines and antiretroviral therapy contributed the most to community-acquired ADRs at the time of hospital admission while medicines used for opportunistic infections (such as antifungals, antibiotics and antituberculosis medicines were most frequently implicated in hospital acquired ADRs. ADRs in HIV-infected patients were less likely to be preventable. AIMS: To describe the frequency, nature and preventability of community-acquired and hospital-acquired adverse drug reactions (ADRs) in a South African hospital serving a community with a high prevalence of human immunodeficiency virus (HIV)/ acquired immunodeficiency syndrome. METHODS: A 3-month prospective observational study of 665 adults admitted to two medical wards. RESULTS: Forty-one (6.3%) patients were admitted as a result of an ADR and 41 (6.3%) developed an ADR in hospital. Many of the ADRs (46.2%) were considered preventable, although less likely to be preventable in HIV-infected patients than in those with negative or unknown HIV status (community-acquired ADRs 2/24 vs. 35/42; P < 0.0001; hospital-acquired ADRs 3/25 vs. 14/26; P = 0.003). Patients admitted with ADRs were older than patients not admitted with an ADR (median 53 vs. 42 years, P = 0.003), but 60% of community-acquired ADRs at hospital admission were in patients <60 years old. Among patients <60 years old, those HIV infected were more likely to be admitted with an ADR odds ratio (OR) 2.32, 95% confidence interval (CI) 1.17, 4.61; P = 0.017. Among HIV-infected patients, those receiving antiretroviral therapy (ART) were more likely to be admitted with an ADR than those not receiving ART (OR 10.34, 95% CI 4.50, 23.77; P < 0.0001). No ART-related ADRs were fatal. Antibiotics and drugs used for opportunistic infections were implicated in two-thirds of hospital-acquired ADRs. CONCLUSIONS: ADRs are an important, often preventable cause of hospitalizations and inpatient morbidity in South Africa, particularly among the elderly and HIV-infected. Although ART-related injury contributed to hospital admissions, many HIV-related admissions were among patients not receiving ART, and many ADRs were associated with medicines used for managing opportunistic infections.