Prevalence of microalbuminuria and associated risk factors among adult Korean hypertensive patients in a primary care setting.

Microalbuminuria is an early sign of nephropathy and an independent predictor of end-stage renal disease. The purpose of this study was to assess microalbuminuria prevalence and its contributing factors in Korean hypertensive patients. This cross-sectional study enrolled male and female patients of ≥35 years old with an essential hypertension diagnosis as made by 841 physicians in primary care clinics and 17 in general hospitals in the Republic of Korea between November 2008 and July 2009. To assess microalbuminuria prevalence, urine albumin/creatinine ratio (UACR) was measured in patients with a positive dipstick test. Of the 40,473 enrolled patients, 5713 (14.1%) had a positive dipstick test. Of 5393 patients with a positive dipstick test and valid UACR values, 2657 (6.6%) had significantly elevated UACR (≥30 μg mg(-1)), 2158 (5.4%) had microalbuminuria (30 μg mg(-1)≤UACR <300 μg mg(-1)) and 499 (1.2%) had macroalbuminuria (UACR ≥300 μg mg(-1)). Based on multivariate analysis, independent factors associated with elevated UACR included low adherence to antihypertensive medication (23% higher; P=0.042), poorly controlled blood pressure (BP; 38% higher for systolic BP/diastolic BP ≥130 mm Hg/≥80 mm Hg; P<0.001), obesity (47% higher for body mass index (BMI) ≥25.0 kg m(-2); P<0.001), age (17% lower and 58% higher for age categories 35-44 years (P=0.043) and >75 years (P<0.001), respectively) and a prior history of diabetes (151% higher; P<0.001) and kidney-related disease (71% higher; P<0.001). The prevalences of elevated UACR and microalbuminuria were 6.6% and 5.4%, respectively. Age, increased BMI, presence of comorbidities, poor medication adherence and inadequately controlled BP were independent predictors of elevated UACR after controlling for potential confounders.