Insulin resistance-related differences in the relationship between left ventricular hypertrophy and cardiorespiratory fitness in asymptomatic newly diagnosed hypertensive Black sub-Saharan Africans

Abstract

Abstract Background Left ventricular hypertrophy (LVH) is associated with impaired cardiorespiratory fitness (CRF), a surrogate marker of poor outcome. Insulin resistance (IR) plays a central role in all stages of cardiovascular disease continuum. Purpose This study evaluates IR-related differences in the relationship between left ventricular mass (LVM) and CRF in asymptomatic newly diagnosed hypertensive patients. Methods In this cross-sectional observational study, 126 asymptomatic newly diagnosed hypertensive participants (50.5±9.5 years) underwent comprehensive resting transthoracic echocardiographic examination and maximal incremental cardiopulmonary exercise test (CPET). CRF was estimated in peak oxygen uptake (VO2 peak). CPET results were compared between participants with and without LVH. Multivariate analysis examined the influence of IR on the observed differences. Results Those with LVH had lower VO2 peak (15.7±5.5 mL min–1 kg–1 vs. 18.4±3.7 mL min–1 kg–1; p=0.001) than those without LVH. In patients with IR, LVM (r=−0.261, p=0.012), LVM indexed to body surface area (LVMIbsa; r=−0.229, p=0.027), and LVM indexed to height to an allometric power of 2.7 (LVMIh2.7; r=−0.351, p=0.001), and VO2 peak were negatively correlated. In hypertensive patients without IR, these same parameters and VO2 peak have no significant correlation. Body mass index (BMI), LVM, and LVMIbsa emerged as independent determinants of VO2 peak, explaining 46.9% of its variability (overall p=0.001) in IR participants, a relationship not found in participants without IR. Conclusions IR may participate in the deterioration of CRF associated with LVH. Targeting IR in hypertensive patients with LVH could improve prognosis. Funding Acknowledgement Type of funding sources: None.