Beta-blocker target dosing and tolerability in a dedicated heart failure clinic in Johannesburg.

Abstract

Despite the significant clinical benefits of beta-blockers in heart failure with reduced ejection fraction (HFrEF), prescription for and adherence to these agents is reported to be poor. There are few data on the use and tolerance of beta-blocker therapy in patients with HFrEF in South Africa and it is unknown whether these patients would benefit from further heart rate-lowering therapy. Data from all patients with HFrEF attending the heart failure clinic of Charlotte Maxeke Johannesburg Academic Hospital from January 2000 to December 2014 were retrospectively collected. We first determined the rates of beta-blocker intolerance in this population and then categorised the patients according to their most recent dose of beta-blocker (low, moderate or target dose) in order to identify factors associated with beta-blocker intolerance. Lastly, we used the data to identify patients who would be suitable for further treatment with heart rate-lowering therapy. Five hundred patients, with a median follow up of 58.7 months, were identified during the study period. Black South Africans constituted the majority (66.4%) and most patients had HFrEF due to hypertension (32.8%). At the last recorded clinic visit at the end of the study period, 489 patients (97.8%) were taking a beta-blocker with 59.8% prescribed a beta-blocker at target dose. Consistent with previous data, bradycardia was the commonest cause for failing to reach target beta-blocker dose. Only 61 (12%) patients were on no (n = 11) or low (n = 50) dose of beta-blocker at final clinic visit. As per current guidelines, only 10.6% (n = 53) of this cohort of patients would qualify for further treatment with heart rate-lowering therapy. In a dedicated heart failure clinic in South Africa, beta-blockers were well-tolerated in the treatment of HFrEF. The potential role of specific heart rate-lowering therapy in patients treated adequately with heart failure medication and proper up-titration of beta-blockers is relatively small.