Atrial fibrillation and mortality in outpatients with heart failure in Tanzania: a prospective cohort study

OBJECTIVE: In recent years, the prevalence and mortality of heart failure (HF) and other associated cardiovascular diseases have doubled in sub-Saharan Africa (SSA). Studies in high-income countries indicate that HF with concurrent atrial fibrillation (AF) is linked to increased mortality. Our objective was to determine the incidence and clinical outcomes of AF among patients with HF in SSA. DESIGN: A prospective cohort study using data collected between October 2018 and May 2020. SETTING: Outpatient clinic at a tertiary hospital in Mwanza, Tanzania. PARTICIPANTS: 303 adult participants (aged ≥18 years) with HF as defined by the European Society of Cardiology guidelines (2016) and 100 adults with HF as defined by clinical criteria alone were enrolled into the study. Patients with comorbid medical condition that had prognosis of <3 months (ie, advance solid tumours, advance haematological malignancies) were excluded. METHODS: Participants were screened for AF, and their medical history, physical examinations and sociodemographic information were obtained. Multivariable logistic regression models were used to examine factors associated with AF incidence. Cox regression models were used to analyse 3-month mortality and its associated risk factors. RESULTS: We enrolled 403 participants with HF (mean age 60±19 years, 234 (58%) female). The AF prevalence was 17%. In multivariable models, factors associated with AF were low income, alcohol consumption and longer duration of HF. At the end of the 3-month follow-up, 120 out of 403 (30%) participants died, including 44% (31/70) of those with AF. Higher heart rate on ECG, more severe New York Heart Association HF class, rural residence and anaemia were significantly correlated with mortality. CONCLUSION: AF is common, underdiagnosed and is associated with significant mortality among outpatients with HF in Tanzania (HR 1.749, 95% CI 1.162 to 2.633, p=0.007). Our findings additionally identify tachycardia (>110 bpm, HR 1.879, 95% CI 1.508 to 2.340, p<0.001) as an easily measurable, high-impact physical examination finding for adverse outcomes in patients with HF.