Kidney function and risk factors for left ventricular hypertrophy in untreated uncomplicated essential hypertension

Background: Left ventricular (LV) hypertrophy and decreased kidney function are well-established cardiovascular risk factors in hypertensive patients. Study Design: We investigated the relationship between creatinine level, creatinine clearance, and estimated glomerular filtration rate (eGFR) with LV mass (LVM) in a cross-sectional study. Predictors: eGFR and serum creatinine level. Outcome: LVM index (LVMI). Setting & Participants: 400 patients with untreated uncomplicated essential hypertension. Measurements: LVMI, eGFR (Modification of Diet in Renal Disease Study equation), Framingham risk factors, and a series of specific risk factors, ie, endothelial function (acetylcholine [ACh]-stimulated forearm blood flow [FBF]), insulin sensitivity (Homeostatic Model Assessment for insulin resistance [HOMA-R] index), C-reactive protein (CRP), and uric acid. Results: Both eGFR and creatinine level were significantly related to LVMI (r = -0.34 and r = 0.35; P < 0.001). In a multiple regression model adjusting for Framingham risk factors, eGFR was independently associated with LVMI. However, this association, although highly significant, lost substantial strength after adjustment for such specific risk factors as HOMA-R index, ACh-stimulated FBF, CRP level, and uric acid level. eGFR interacted with insulin resistance in explaining the variability in LVMI (P = 0.007). Limitations: The cross-sectional nature of this study precludes cause-effect conclusions. Conclusions: Independently of other risk factors, decreased kidney function contributes to explain the variability in LVMI in patients with untreated uncomplicated essential hypertension. This association is attributable in part to the link between eGFR and such specific risk factors as HOMA-R index, ACh-stimulated FBF, CRP level, and uric acid level. Decreased kidney function and insulin resistance interact in explaining the variability in LVMI in these patients.