Hyperkalaemia in patients with heart failure in German general practices: prevalence, diagnosis and treatment: The WATCH-K study

Abstract Background Patients with heart failure (HF) are at high risk of developing hyperkalaemia (HK). The risk is further increased by cardioprotective treatment with renin-angiotensin-aldosterone system inhibitors (RAASi), angiotensin receptor-neprilysin inhibitors and mineralocorticoid receptor antagonists as part of the currently guideline-recommended therapy of HF with reduced ejection fraction. HK can be life-threatening and is associated with a poor prognosis. The ESC HF guidelines therefore recommend regular, close monitoring of potassium levels in patients at increased risk of HK (every 4 months with RAASi therapy1), and the use of potassium binders (PB) to maintain RAASi therapy in hyperkalaemic patients.2 Care provided by general practitioners (GP) is essential for long-term treatment of patients with HF and HK, however, there are insufficient data on the HK management in HF patients in German GP practices. Purpose The aim of this analysis was to determine the prevalence of HK in HF patients in German GP practices, and to assess the current real world practice regarding HK screening, diagnosis and treatment. Methods For this secondary data analysis of HF patients, anonymised electronic datasets from German GP practices from December 2020 to July 2023 were analysed for a follow-up period of ≥1 year. All patients with a documented ICD-10 code for HF (I50.-) were included. Results Data from 53,273 HF patients from 1,238 German GP practices were analysed. Of these, 76.3% (n=40,637) received RAASi therapy (ACEi/ARB) during the follow-up period. In 55.3% (n=22,483) of HF patients with RAASi and 57.2% (n=30,467) of all HF patients, no potassium measurement was recorded during the follow-up period. Among HF patients with ≥1 potassium measurement (n=22,806), 32.9% (n=7,497) had HK, defined as a serum potassium level 5 mmol/L (Table 1). In 96.8% (n=7,257) hyperkalaemic patients no ICD-10 diagnosis (E87.5) was noted (Figure 1). Of the HF patients with an HK diagnosis (n=240), 86.3% (n=207) were not treated with PB during the follow-up period. Of those who were treated with a PB, the majority received a traditional PB (87.9%, SPS and/or CPS), and the minority a modern PB (15.2%, SZC or Patiromer). In the subgroup of patients treated with PB (n=107), 59.8% (n=64) received only one PB prescription during the follow-up period. Conclusions The WATCH-K study revealed that potassium measurements, HK diagnoses and targeted treatment with guideline-recommended PB are only carried out to a limited extent in German GP practices, despite HF being associated with an increased risk for HK. Our data suggest that PB treatment is mainly short-term treatment, as most patients received only one prescription in ≥1 year. Therefore, the results of the WATCH-K study clearly show that more awareness among GPs for high HK levels in HF patients is urgently needed to avoid potentially life-threatening consequences of HK and to enable guideline-directed HF therapy.Baseline characteristics Treatment with potassium binders