Obesity paradox in patients with reduced ejection fraction eligible for device implantation - an observational study.
Objective: Patients with obesity have an overall higher cardiovascular risk, at the same time obesity could be associated with a better outcome in a certain subgroup of patients, a phenomenon known as the obesity paradox. Data are scarce in candidates for cardiac resynchronization therapy (CRT). We aimed to investigate the association between body mass index (BMI) and all-cause mortality in patients eligible for CRT.
Methods: Altogether 1,585 patients underwent cardiac resynchronization therapy between 2000-2020 and were categorized based on their BMI, 459 (29%) patients with normal weight (BMI < 25 kg/m2), 641 (40%) patients with overweight (BMI 25- < 30 kg/m2) and 485 (31%) with obesity (BMI ≥ 30 kg/m2). The primary endpoint was all-cause mortality, heart transplantation, and left ventricular assist device implantation. We assessed periprocedural complications and 6-month echocardiographic response.
Results: Normal-weight patients were older compared to patients with overweight or obesity (70 years vs. 69 years vs. 68 years; P ‹0.001), respectively. Sex distribution, ischaemic aetiology, and CRT-D implantation rates were similar in the three patient groups. Diabetes mellitus (BMI < 25 kg/m2 26% vs. BMI 25- < 30 kg/m2 37% vs. BMI ≥ 30 kg/m2 48%; P ‹0.001) and hypertension (BMI < 25 kg/m2 71% vs. BMI 25- < 30 kg/m2 74% vs. BMI ≥ 30 kg/m2 82%; P ‹0.001) were more frequent in patients with overweight and obesity. During the mean follow-up time of 5.1 years, 973 (61%) reached the primary endpoint, 66% in the BMI < 25 kg/m2 group, 61% in the BMI 25- < 30 kg/m2 group and 58% in the BMI ≥ 30 kg/m2 group (log-rank P‹0.05). Patients with obesity showed mortality benefit over normal-weight patients (HR 0.78; 95%CI 0.66-0.92; P = 0.003). The obesity paradox was present in patients free from diabetes, atrial fibrillation, and ischemic events. Periprocedural complication rates did not differ in the three groups (BMI < 25 kg/m2 25% vs. BMI 25- < 30 kg/m2 28% vs. BMI ≥ 30 kg/m2 26%; P = 0.48). Left ventricular ejection fraction improved significantly in all patient groups (BMI < 25 kg/m2 median