Differential Association Between Ten Indices of Insulin Resistance and End-Organ Damage in a Community of African Ancestry in Africa

<b>Objective:</b> Various insulin resistance (IR) indices have been developed to assess cardiovascular (CVS) risk. We compared the association between ten IR indices and cardiac, renal, and vascular end-organ measures in a predominantly young (age 45.0 ± 18.3 years) South African Black population. <b>Methods:</b> We assessed the relationships between ten IR indices (homeostatic model assessment for IR [HOMA-IR], quantitative insulin sensitivity check index [QUICKI], metabolic score for IR [METS-IR], triglyceride-glucose index [TyG], TyG-body mass index [TyG-BMI], TyG-waist circumference [TyG-WC], TyG-waist-to-height ratio [TyG-WHtR], triglyceride to high-density cholesterol concentration [TyG-HDL], lipid accumulation product [LAP], visceral adiposity index [VAI]) and end-organ measures in 779 community participants of African ancestry. <b>Results:</b> HOMA-IR and QUICKI were the only IR indices consistently associated with end-organ measures (left ventricular [LV] mass index, <i>p</i> ≤ 0.005; LV relative wall thickness, <i>p</i> < 0.0001; early-to-late mitral velocity, <i>p</i> ≤ 0.01; E/e', <i>p</i> ≤ 0.002; e', <i>p</i> < 0.0001; pulse wave velocity, <i>p</i> = 0.036 (HOMA-IR only); glomerular filtration rate [GFR], <i>p</i> < 0.0001), independent of confounders. Furthermore, HOMA-IR was consistently higher, and QUICKI lower, in those with compared to those without end-organ damage (LV hypertrophy [<i>p</i> ≤ 0.03], concentric LV [<i>p</i> < 0.03], and reduced GFR [<i>p</i> ≤ 0.008]), independent of confounders. Importantly, the associations between HOMA-IR or QUICKI and end-organ measures were independent of additional CVS risk factors, including adiposity measures, and were replicated in the participants without diabetes mellitus (n = 669) and in the participants without high blood pressure (n = 505). <b>Conclusions:</b> In a predominantly young community of African ancestry, of ten recommended IR indices, only HOMA-IR and QUICKI were consistently associated with end-organ damage independent of CVS risk factors.