The prevalence, characteristics, and clinical significance of abnormal albuminuria in patients with hypertension

Abstract

Kidney function and cardiovascular disease are closely connected and albuminuria is a proven marker of cardiovascular risk. The present study investigated the prevalence and characteristics of albuminuria in patients with hypertension. Outpatients with essential hypertension under medical treatment were enrolled in this study (n = 350, 70.0 ± 11.4 years old). Urine samples were collected for the measurement of albumin concentration, which are expressed as the ratio of urine albumin to creatinine concentration (mg/g Cr). Cross-sectional analyses were also performed of the relationships between urinary albumin and other variables. Urinary albumin was detected in 88.3% of patients, while only 35.4% showed abnormal albuminuria (≥30 mg/g Cr). The presence of abnormal albuminuria was independently correlated with systolic blood pressure, B-type natriuretic peptide, and C-reactive protein by multivariate analysis (P < 0.05). Furthermore, multivariate regression analysis identified systolic blood pressure, serum creatinine, B-type natriuretic peptide, and C-reactive protein as the only factors showing independent correlation with urinary albumin (P < 0.05). Thus, approximately 35% of hypertensive patients had abnormal albuminuria. Urinary albumin was closely associated with blood pressure, C-reactive protein, and B-type natriuretic peptide, indicating that the severity of albuminuria parallels that of systemic inflammation, cardiac load, and blood pressure.

Figure 1. The distribution of urinary albumin in patients with hypertension.

Urinary albumin was detected in 88.3% of hypertensive patients and 35.4% of patients showing abnormal albuminuria.

Figure 2. Relationship of urinary albumin with (a) B-type natriuretic peptide (BNP) and (b) C-reactive protein (CRP) in hypertensive patients.

The median value [range] of the urinary albumin to creatinine ratio (mg/g creatinine) was 6.0 [0–10.0], 15.0 [11.0–21.0], 28.0 [22.0–45.0], and 112 [45.0–3013] in Quartile 1, 2, 3, and 4, respectively. *P < 0.01, **P < 0.001 vs. quartile 1.