What characterizes normotensive individuals with obesity and normal systolic heart function? A descriptive study from the SCAPIS cohort

Abstract Background Heart failure and cardiovascular disease are strongly related to obesity, and the incidence of these conditions shows a linear relationship with increasing body mass index (BMI). Despite these known facts, some individuals with obesity show no clinical signs of heart disease or arterial hypertension (AH). Purpose We aimed to investigate the characteristics of individuals with obesity without impaired left ventricular function and left ventricular hypertrophy (termed systolic heart function, SHF) and AH, compared to individuals with obesity with signs of impaired SHF or AH, and individuals without obesity with and without signs of impaired SHF or AH. Method A cross-sectional analysis was performed of the 4,692 individuals who had undergone a transthoracic echocardiography within the Swedish CArdioPulmonary bioImage Study (SCAPIS). Participants were divided into four groups: 1) individuals with obesity (BMI³30 kg/m2) without impaired SHF (normal left ventricular systolic function and left ventricular mass) and no AH (based upon the absence of antihypertensive treatment) (ObSHF/AH-, n=623; 13%), 2) individuals with obesity with impaired SHF or AH (ObSHF/AH+, n=252; 5%), 3) individuals without obesity and without impaired SHF and no AH (NObSHF/AH-, n=3179; 68%) and 4) individuals without obesity with impaired left ventricular systolic function, left ventricular hypertrophy or AH (NObSHF/AH+, n=638; 14%). Individuals in group 1 (ObSHF/AH-;) were compared to those in groups 2-4 through descriptive analyses. Results Compared to ObSHF/AH+ individuals, ObSHF/AH- subjects showed significantly lower HbA1c (p<0.001), fasting plasma glucose (p<0.001), triglyceride (p<0.001), NT-proBNP (p=0.035) and troponin I (p<0.001) levels. Furthermore, no significant differences between the two obese groups could be seen regarding BMI (p=0.074), whereas waist-to-hip ratio was lower in ObSHF/AH- subjects (p<0.001). ObSHF/AH- individuals had higher glucose and lipid levels as well as higher blood pressure than individuals without obesity. Interestingly, no differences were seen between ObSHF/AH- and NObSHF/AF- subjects regarding NT-proBNP (p=0.864) and troponin I levels (p=0.110). Furthermore, left ventricular mass index (LVMI) was significantly higher in ObSHF/AH- subjects compared to NObSHF/AH- individuals (73.8 vs. 72.1 g/m2, p=0.015) and the ejection fraction was significantly lower (57.4 vs. 59.6 %, p<0.001). Conclusion When ObSHF/AH- and NObSHF/AH- subjects were compared, markers of cardiac damage/remodeling did not differ significantly, indicating that heart function might be preserved despite a worsened metabolic profile and an obese phenotype, through putative protective mechanisms yet to be explored. However, parameters of SHF were unfavorable for ObSHF/AH- when compared to NObSHF/AH-, further implicating preclinical cardiac impairment in individuals with obesity.