Use of metolazone in the community setting for heart failure decompensation: is it worthwhile?

Background/Aims There are more than 900 000 people living with heart failure in the UK. The risk of hospitalisation for heart failure is even higher in patients with underlying chronic kidney disease with diuretic resistance. Prescribers can be apprehensive about prescribing metolazone for use in the community setting because of a perceived risk of renal function deterioration and electrolyte imbalance. This study explores issues around the safety of metolazone use in the community setting, aiming to demonstrate whether this is useful for the prevention of hospitalisation. Methods Data were collected retrospectively on patients who had been newly initiated on metolazone by the authors' London-based specialist heart failure service to treat decompensation during the 3-year period from June 2017 to June 2020. The renal function, incidence of hypokalaemia and hospital admissions of included patients (n=23) were analysed. Results Overall, 65% of patients did not require hospitalisation following initiation of metolazone. Most patients did experience a decline in estimated glomerular filtration rate, with an average decline of 21%, although only one patient experienced a severe decline. Of the three patients who experienced hypokalaemia, all were treated with oral potassium and did not require hospitalisation. Conclusions Metolazone requires good support and follow up from heart failure nurses or other heart failure specialists, but can be safe and effective in the community setting. In patients with heart failure and diuretic resistance, the risks of avoiding metolazone may be higher than the risks of administering it.