Background: New pharmacological therapies improved outcomes of patients with heart failure (HF) significantly as shown in recent randomized controlled trials. It remains questionable whether these effects can also be transferred to general patient care since data in this regard is limited. Before evaluating novel drugs in large real-world HF cohorts, understanding patient characteristics, burden of comorbidities, and treatment paths is crucial which is the he aim of the multinational CaReMe study (observational study to further highlight the epidemiology and healthcare burden of CArdiovascular-REnal-MEtabolic diseases in (BEL, CAN, ESP, GBR, GER, ISR, ITA, NOR, POR, SUI, SWE), with the here presented German substudy.

Purpose: To describe contemporary HF patient characteristics and HF-related outcomes in a real-world setting using multicenter, nationwide claims data.

Methods: This study utilized claims data from all German Helios hospitals extracting ICD-10-encoded main and secondary diagnoses at hospital discharge as well as procedures performed. Two cohorts were built with index cases defined as the first full inpatient cases between January 1^st and December 31^st 2018 with either a main diagnosis (MD) of HF (ICD-10: I11.00, I11.01, I13.00, I13.01, I13.20, I13.21, I25.5, I42.0, I42.6, I42.7, I50) or a secondary diagnosis (SD) of HF in combination with a cardiovascular main diagnosis (ICD-10: I01-I99; excluding I89.0, I97.2, I97.8, I97.80-88). Patient characteristics and specific event rates were described within hospital readmissions during one year from index discharge date (or end of observational period).

Results: Cohorts consisted of 31,120 and 63,636 patients with MD or SD of HF. Patients with MD of HF were 76.6±11.5 years old on average, had frequent comorbidities (hypertension (HT): 72%; chronic kidney disease (CKD): 59.7%; atrial fibrillation/flutter (AF/F): 50.3%; prior myocardial infarction (MI): 11%; peripheral artery disease (PAD): 7.2%; prior stroke: 3.9%) and were highly symptomatic (NYHA I/II: 12%; NYHA III: 43.7%; NYHA IV: 35.7%). In-hospital mortality within index cases was 4.7%. During follow-up (FU), 99.1 readmissions per 100 patient years (PY) were observed with HF as the predominant readmission cause (28.9). In-hospital mortality during FU was 6.6%. Patients with SD of HF were younger (mean age 74.4±11.7), had a differing composition of comorbidities (HT: 77.8%; CKD: 53.1%; AF/F: 38.2%; prior MI: 11.9%; PAD: 7.9%; prior stroke: 4.8%) and less severe symptoms (NYHA I/II: 27.2%; NYHA III: 40.1%; NYHA IV: 21.4%). Fewer patients met endpoints during FU (all readmissions: 79.8 events per 100 PY, HF-related readmissions: 16.6 per 100 PY) and in-hospital mortality rates were 4.9% (index case) and 4.2% (FU), respectively. Female gender was less frequent in the SD-cohort compared to the MD-cohort (42.2% vs. 50.1%).