Pattern of antimalaria treatment and risk factors for torsades de pointes in admitted heart failure patients in Lagos-Nigeria

Abstract

Background: In a malaria-holoendemic region, concurrent malaria complicating heart failure (HF) occurs; with higher morbidity and increased adverse drug-drug interactions. Aim: To characterise malaria treatment and risk factors of cardio-toxicity among HF patients. Objectives: To characterise the use of anti-malaria agents (AMA), compare risk factors of torsades de pointes (TdP) amongst AMA-users and non-users, and to assess length of hospital stay. Methods: Admitted HF patients were retrospectively studied, and grouped on the basis of malaria treatment. TdP risk factors- advanced age, bradycardia, hypokalemia, and QTc prolongation were compared in the two groups. Results: The 160 HF patients (mean ejection fraction 39.6% ± 12.6%, mean age 54.9 ± 14.6 years) included 82 males (51.3%), with predominant non-ischemic HF. Malaria treatment occurred in 32.5% (52), though diagnosis was presumptive in 48 (92.3%). All (100%) malaria prescriptions were artemisinin-based, but monotherapeutic in 6 (11.4%). Partner-drugs included sulphadoxine-pyrimethamine (SP) 26 (50%), and lumefantrine 7 (13.5%). TdP risk-factors of age 65 years, prolonged QTc, hypokalemia, and bradycardia occurred in 43 (26.9%), 63 (39.4%), 48 (30%), and 8 (5.0%) respectively. Group 1 (AMA treated) and group 2 patients were comparable on all mean values of risk factors. Nevertheless, affected proportions were significantly different for hypokalemia (X2 = 6.1), QTc prolongation (48.1% versus 35.2%, p < .05), and older age (38.5% versus, 21.3%, p < .05%). Conclusion: Though all HF patients similarly demonstrated risks of TdP, univariate analysis indicates a significantly higher proportion in malaria-treated patients; supporting further therapeutic caution in this patient subset.