Aims
Heart failure (HF) is an increasing concern worldwide. A rising HF burden is expected due to the prospected future demographic changes with aging populations. Consequently, the long-term follow-up and treatment will be performed increasingly by primary care physicians in the future. Contemporary data on HF patients in primary care are needed to plan and ensure an effective and safe follow-up of future patients.

Methods and results
The electronic patient journals of 148 primary care clinics in Denmark were searched in a standardized manner to identify patients with HF [code K77 of the International Classification of Primary Care, Second Edition]. Prespecified variables including demographic information, clinical variables, co-morbidities, prescribed medications, and setting of follow-up were recorded. In total, 1111 patients were included in the study. The mean timepoint for the HF diagnosis was August 2018. In 95% of cases, the diagnosis of HF was made in a specialized setting. The echocardiogram data used for phenotyping were available in 1042 (94%) of the 1111 patients. HF with reduced ejection fraction (HFrEF) was present in 43%, recovered HFrEF in 31%, and HF with mildly reduced (HFmrEF) or preserved ejection fraction (HFpEF) in 26%. In patients with HFrEF or recovered HFrEF, fundamental treatments were prescribed in 86% for angiotensin converting enzyme inhibitor (ACEI), angiotensin receptor blocker (ARB), or angiotensin receptor neprilysin inhibitor (ARNI), in 82% for beta-blocker, in 38% for mineralocorticoid receptor antagonist (MRA), and in 12% for sodium-glucose co-transporter-2 inhibitor (SGLT2i). Older patients were treated to a significantly lesser extent than young patients for all drug classes [odds ratio (OR) point estimates 0.50 to 0.69, all P-values < 0.05]. In patients with HFmrEF or HFpEF, an ACEI, ARB, or ARNI was prescribed in 67%, beta-blocker in 67%, MRA in 22%, and SGLT2i in 7.4% with significantly lower probability of treatment compared to patients with HFrEF or recovered HFrEF [OR point estimates 0.33 to 0.57, all P-values < 0.05]. The setting of follow-up was available in 96% of patients. Irrespective of HF phenotype, follow-up was performed solely in primary care in 64%. These patients were generally treated to a lesser extent with HF therapies compared with patients where follow-up included specialized care, yet differences were generally small.

Conclusions
HFrEF is the most common phenotype of HF in primary care followed by recovered HFrEF and fundamental therapies are markedly underutilized. Initiatives to increase the use of recommended therapies are needed to improve the future care of patients with HF.