Low-Grade Albuminuria Is Associated with Left Ventricular Hypertrophy and Diastolic Dysfunction in Patients with Hypertension

Abstract

Introduction: Microalbuminuria is a risk factor for cardiovascular morbidity and mortality in hypertensive patients. However, the relationship between low-grade albuminuria, a higher level of albuminuria below microalbuminuria threshold, and hypertension-related organ damage is unclear. Left ventricular (LV) hypertrophy (LVH) is well recognized to be a subclinical organ damage of hypertension, and LV diastolic dysfunction is also reported to be an early functional cardiac change of hypertension that predicts heart failure. The present study aimed to investigate the association of low-grade albuminuria with LVH and LV diastolic dysfunction in hypertensive patients.

Methods: This cross-sectional observational clinical study was retrospectively performed in 870 hypertensive patients admitted to our hospital. Urinary albumin to creatinine ratio (UACR) was calculated to assess the levels of albuminuria: macroalbuminuria (≥300 mg/g), microalbuminuria (≥30 mg/g, but <300 mg/g), and normal albuminuria (<30 mg/g). Low-grade albuminuria was defined as sex-specific highest tertile within normal albuminuria (8.1-29.6 mg/g in males and 11.8-28.9 mg/g in females). LVH and LV diastolic dysfunction were identified as recommended by American Society of Echocardiography.

Results: Of the 870 patients, 765 (87.9%) had normal albuminuria, 77 (8.9%) had microalbuminuria, and 28 (3.2%) had macroalbuminuria. Percentage of LVH and LV diastolic dysfunction was increased with ascending UACR. UACR was independently associated with LVH and LV diastolic dysfunction, even in patients with normal albuminuria. Multivariable logistic regression showed that the patients with the highest tertile within normal albuminuria had nearly 80% increase in LVH and nearly 60% increase in LV diastolic dysfunction (adjusted OR for LVH 1.788, 95% CI 1.181-2.708, p = 0.006; adjusted OR for LV diastolic dysfunction 1.567, 95% CI 1.036-2.397, p = 0.034). After further stratification analyses in patients with normal albuminuria, it was shown that this independent association persisted in female patients, those who were younger than 70 years old, and those with duration of hypertension <15 years.

Conclusion: Low-grade albuminuria was associated with LVH and LV diastolic dysfunction in hypertensive patients, especially in patients younger than 70 years old, and those with duration of hypertension <15 years.

Keywords: Hypertension; Left ventricular diastolic dysfunction; Left ventricular hypertrophy; Low-grade albuminuria.