The Metabolic Syndrome, Cardiovascular Fitness and Survival in Patients With Advanced Systolic Heart Failure

Abstract

The metabolic syndrome (MetS), which incorporates insulin resistance, visceral adiposity, and dyslipidemia, is an independent risk factor for incident heart failure (HF), but the impact on survival is uncertain. We sought to determine the relation between the metabolic syndrome and survival in ambulatory systolic HF patients and the impact of MetS on cardiopulmonary exercise test (CPET). We identified adults with ejection fraction ≤40% who underwent CPETs between 2000 and 2011. Baseline MetS status was defined by 3 or more of: (1) Triglycerides ≥150 mg/dl; (2) High density lipoprotein <40 mg/dl males or <50 mg/dl females; (3) Diabetes mellitus; (4) Hypertension; (5) Body mass index ≥35 kg/m². Minimally-adjusted (for age, sex, transplantation and left ventricular assist device implantation) and fully-adjusted Cox proportional hazards models were constructed for all-cause mortality. MetS prevalence was 37% (716 of 1,953) and median follow-up 5 years. Mortality was 36% for +MetS and 29% for -MetS (p = 0.006), with highest mortality in the subgroup with both MetS plus diabetes (39%). The minimally-adjusted hazard ratio for mortality with MetS was 1.27 (95% confidence interval, 1.08 to 1.49, p = 0.004). After adjustment, MetS was no longer independently associated with mortality (hazard ratio 1.01, 95% confidence interval 0.85 to 1.19, p = 0.921). Patients with MetS achieved poorer CPET performance compared and MetS was independently associated with a lower peak VO₂. MetS was associated with a higher hazard of mortality in the minimally-adjusted model, which was primarily driven by the unfavorable impact of diabetes on mortality, but this association was no longer significant after full adjustment. In conclusion, there was no independent association between MetS and survival in an ambulatory systolic HF population.