Abstract 13502: Obesity Paradox in Severe Rheumatic Mitral Stenosis: A Prospective Analysis Using a Machine Learning-Based Approach

Background: The obesity paradox posits that obese patients have better prognosis in cardiovascular diseases. Scarce data exists on the obesity paradox in rheumatic mitral stenosis (RMS)

Hypothesis: Obesity is associated with a favorable prognosis in severe RMS

Methods: Patients with severe RMS referred to a tertiary center from 2011 to 2022 were prospectively included. Patients with previous valve interventions were excluded; clinical and echocardiographic data were collected at baseline. Severe RMS was defined as a mitral valve area ≤ 1.5 cm2 by planimetry and patients were divided into 2 groups: (1) BMI ≥ 30 kg/m ² ; (2) BMI < 30 kg/m ² . A combined outcome of percutaneous mitral valvuloplasty, mitral replacement and cardiovascular death was set. Logistic regression adjusted for confounders and gradient boosted decision-tree analysis were used

Results: A total of 315 patients (82.2% female, mean age 53.3 years) were included. Over a median follow up of 30 months, 87% of patients had the outcome. MVA was higher in group 1 (p<0.001) while left atrial volume index (LAVi) and net atrioventricular compliance were lower (p=0.008 both). Overall, BMI was not a good independent predictor of outcome (OR 0.98, 95% CI: 0.91-1.06, p=0.50) and occurrence of outcome was similar between groups (p=0.481). In both groups, mean importance of BMI in determining the outcome was similar (17.7 ± 6.1% and 17.0 ± 2.6% respectively)

Conclusion: Obese patients had higher MVA and lower LAVi. However, our data suggests that BMI was not a significant independent predictor of poorer prognosis and its importance was not different between the groups. These findings challenge the obesity paradox in severe RMS