Baseline BMI and weight change in dilated cardiomyopathy: associations with LVEF, BNP, and NYHA class

Baseline body mass index (BMI) and longitudinal weight change capture different clinical dimensions. We examined their concurrent associations with 12-month changes in left ventricular ejection fraction (LVEF), B-type natriuretic peptide (BNP), and New York Heart Association (NYHA) functional class among patients with dilated cardiomyopathy.

Of 600 records screened, 322 patients had complete paired baseline and 12-month measurements and were included in this retrospective cohort analysis. Percentage weight loss was calculated as 100 × (baseline weight-12-month weight)/baseline weight; negative values denoted weight gain. Joint models included baseline BMI and weight loss and adjusted for age, sex, log-transformed baseline BNP, baseline LVEF, left ventricular end-diastolic diameter, baseline NYHA class, diabetes, chronic kidney disease, atrial fibrillation, and coronary atherosclerosis.

Thirty-six patients gained weight, six demonstrated no weight change, and 280 lost weight. Baseline BMI was not independently associated with LVEF change (β = -0.099, 95% CI -0.269 to 0.071; P = 0.254), BNP log ratio (β = 0.008, 95% CI -0.014 to 0.030; P = 0.467), or NYHA improvement (OR = 1.02, 95% CI 0.94-1.10; P = 0.709). Each 5% greater weight loss was concurrently associated with a greater increase in LVEF (β = 2.43 percentage points, 95% CI 1.66-3.20), a lower BNP log ratio (β = -0.317, 95% CI -0.415 to -0.219), and higher odds of NYHA improvement (OR = 1.93, 95% CI 1.38-2.74; all P < 0.001). The associations remained consistent after adjustment for the availability of heart-failure and weight-management therapies.

Twelve-month weight change was associated with concurrent changes in LVEF, BNP, and functional status, whereas baseline BMI was not. These data do not establish temporal direction, causality, or the superiority of weight change as a clinical marker.