Baseline renin levels were a risk factor for unplanned HF hospitalizations (crude HR for an increase of 100 μiE/ml 1.01 (95% CI: 1.00–1.02), p = 0.015), which remained significant for adjusted models I (age, sex, and BMI) and II (model I + additional adjustment for comorbidity type 2 diabetes, coronary artery disease, and hypertension), but not model III (NT-proBNP, NYHA class, and aldosterone). This evidence concerns the gene REN and hydrops fetalis.