Associations of insulin resistance-related metabolic indices with albuminuria in primary hypertension without diabetes: a retrospective cross-sectional study

Background Insulin resistance-related metabolic indices have been associated with albuminuria in general populations and in patients with diabetes, but evidence in patients with primary hypertension without diabetes remains limited. Whether mean arterial pressure (MAP) statistically accounts for part of these associations is unclear. Methods We retrospectively analysed cross-sectional data from 509 hospitalised cardiology patients with primary hypertension without diabetes at a single tertiary centre who underwent urinary albumin-to-creatinine ratio (UACR) testing. Albuminuria was defined as a UACR ≥30 mg/g. Associations of the triglyceride-glucose body mass index (TyG-BMI), metabolic score for insulin resistance (METS-IR), and triglyceride-glucose (TyG) index with albuminuria and log 10 -transformed UACR were examined using multivariable logistic and linear regression. Restricted cubic splines (RCS) assessed the shape of the associations. Supplementary logistic models additionally adjusted for MAP, and exploratory indirect-effect analyses assessed statistical indirect components involving MAP. Results Among the 509 participants, 99 (19.4%) had albuminuria. After multivariable adjustment, the odds ratios (ORs) for albuminuria per 1-SD increment in TyG-BMI, METS-IR, and the TyG index were 1.610 [95% confidence interval (CI), 1.262–2.055], 1.557 (95% CI, 1.215–1.995), and 1.436 (95% CI, 1.128–1.829), respectively. Corresponding Q4-vs.-Q1 ORs were 2.464 (95% CI, 1.228–4.943), 2.665 (95% CI, 1.268–5.600), and 2.137 (95% CI, 1.092–4.181), with overall categorical P -values of 0.018, 0.059, and 0.099, respectively. RCS analyses showed significant overall associations for all three indices, with no statistical evidence of departure from linearity. All three indices were positively associated with log 10 -transformed UACR. After additional MAP adjustment, the continuous associations with albuminuria were attenuated but remained statistically significant for all three indices, whereas the overall tests across quartiles were not statistically significant for any of the three indices. Exploratory analyses suggested statistical indirect components involving MAP for TyG-BMI and METS-IR, but not for the TyG index. Conclusions Higher TyG-BMI, METS-IR, and TyG index values were associated with albuminuria and higher UACR in patients with primary hypertension without diabetes. Exploratory analyses suggested statistical indirect components involving MAP for TyG-BMI and METS-IR, but did not establish temporal ordering or causal mediation.