ADMA, C-reactive protein, and albuminuria in untreated essential hypertension: a cross-sectional study

Abstract

Background: Asymmetric dimethylarginine (ADMA) and subclinical inflammation are associated with atherosclerosis progression, whereas microalbuminuria is an established index of hypertensive organ damage.

Study design: Cross-sectional.

Setting & participants: In an outpatient hypertensive unit, 296 nondiabetic and untreated participants with hypertension were studied. Participants with atherosclerotic cardiovascular disease, severe valvulopathy, congestive heart failure, presence of neoplastic or other concurrent systemic disease, atrial fibrillation, serum creatinine level > 1.5 mg/dL in men and > 1.4 mg/dL in women, and urinary albumin excretion > 300 mg/24 h were excluded.

Predictors: ADMA and high-sensitivity C-reactive protein (hs-CRP) levels.

Outcome variable: Albuminuria assessed using albumin-creatinine ratio (ACR).

Measurements: Participants underwent ambulatory blood pressure monitoring, echocardiography, routine assessment of metabolic profile, ADMA, and hs-CRP, whereas ACR was determined as the mean of 3 values in nonconsecutive morning spot urine samples.

Results: 64 participants had an ACR of 30-300 mg/g. Stratification based on ADMA level showed that participants with hypertension in quartile [Q] 4 compared with those in Q3, Q2, and Q1 showed the highest ACRs (53.2 vs 31.2 vs 30.4 vs 16.7 mg/g; P < 0.008 for all). Moreover, stratification based on hs-CRP level showed that participants with hypertension in Q4 (69.8% had microalbuminuria) showed the highest ACRs (72.2 vs 25.6, 16.2, and 19.2 mg/g for Q3, Q2, and Q1, respectively; P < 0.008 for all). Stepwise regression analysis showed that age, 24-hour systolic blood pressure, hs-CRP level, ADMA level, and the interaction of hs-CRP with ADMA were independent predictors of ACR (R(2) = 0.674; P < 0.001).

Limitations: Cross-sectional study.

Conclusions: In patients with untreated essential hypertension, increased hs-CRP and ADMA levels are associated with microalbuminuria, suggesting the involvement of inflammation and endothelial dysfunction in vascular and kidney damage.