Reduced levels of vasopressin, an independent mechanism in the obesity paradox in patients with chronic heart failure: Insights from the DAMOCLES study.

BACKGROUND: An "obesity paradox" has been described in patients with chronic heart failure (CHF), obese patients having a better survival. Vasopressin is elevated in patients with CHF, and higher levels are associated with worsening severity of the disease. We aimed at evaluating the relationship between body mass index (BMI), obesity (BMI ≥30 kg/m2 ), and vasopressin in patients with CHF, as well as the prognostic implications of vasopressin across the full spectrum of BMI values.

METHODS: We included 1132 consecutive CHF patients referred to a multidisciplinary CHF unit. BMI and vasopressin levels were measured at baseline, and their association was evaluated using multivariable linear and logistic regression models. Death was evaluated after a median follow-up of 2.93 years and using Cox regression analyses.

RESULTS: Mean age was 73 years, 43% women, mean BMI 28 kg/m2 . Vasopressin levels were independently associated with all-cause death across the whole spectrum of BMI values, and were significantly lower in obese as compared to non-obese patients (median adjusted estimated levels of log-vasopressin in obese patients 2.57 [95% CI 1.5-3.67], in non-obese patients 3.16 [95% CI 2.11-4.23]; p < 0.001). Also, the higher the BMI, the lower the vasopressin levels, at least for patients with BMI <35 kg/m2 . Subgroup analyses stratifying by left ventricle ejection fraction and sensitivity analyses further adjusting for norepinephrin levels yielded similar findings.

CONCLUSIONS: Reduced levels of vasopressin may represent an independent mechanism in the survival paradox in obese patients with CHF. Studies including larger samples of patients BMI ≥35 kg/m2 are needed.