Association of low-grade urinary albumin excretion with left ventricular hypertrophy in the general population

BACKGROUND: Even mild renal dysfunction is a predictor of cardiovascular morbidity. We investigated whether sub-threshold microalbuminuria or mildly decreased estimated glomerular filtration rate (eGFR) are related to left ventricular hypertrophy (LVH) in the general population. METHODS: Urinary albumin-to-creatinine ratio (UACR) served to determine albuminuria, eGFR was estimated using modification of diet in renal disease (MDRD) formula, and LV geometry was assessed echocardiographically in the third MONItoring of trends and determinants in CArdiovascular disease/Cooperative Health Research in the Augsburg Area (MONICA/KORA) Augsburg survey (n = 1187). RESULTS: The prevalence of LVH increased in parallel with UACR. Compared with the first tertile of this normal population, the age, systolic blood pressure (SBP), body mass index, gender and diabetes adjusted odds ratio (OR) for LVH was elevated already in the second (4.32-8.75 mg/g in men; 4.60-9.48 mg/g in women; OR: 2.10, P = 0.001) as well as in the third UACR-tertile (> or =8.76 mg/g in men; > or =9.49 mg/g in women; OR: 1.63, P = 0.035). Likewise, adjusted SBP increased with UACR-tertiles [129 vs 132 (P = 0.036) and 137 mmHg (P < 0.001) in the first, second and third tertile, respectively], whereas diastolic blood pressure was significantly elevated only in the third UACR-tertile [79 vs 80 and 81 mmHg (P = 0.002) in the tertiles, respectively]. In contrast, tertiles of eGFR or mildly impaired eGFR (<90 ml/min/1.73 m(2)) were not associated with the prevalence of LVH in multivariate models. CONCLUSIONS: At the general population level, even low-grade albuminuria is associated with LVH. Thus, the conventional UACR-threshold of microalbuminuria (30 mg/g) may be too conservative given that end organ damage such as LVH is observed with increased frequency at much lower levels.