High-normal blood pressure and microalbuminuria

Abstract

Background: High-normal blood pressure (BP) is associated with increased cardiovascular risk compared with optimal BP, but no study has specifically examined the association between high-normal BP and microalbuminuria, an established predictor of future cardiovascular events.

Methods: This was a cross-sectional study of normotensive (systolic BP [SBP] < 140 mm Hg, diastolic BP [DBP] < 90 mm Hg) individuals without diabetes with no hypertension history enrolled in the Third National Health and Nutrition Examination Survey. BP was categorized as high normal (SBP, 130 to 139 mm Hg or DBP, 85 to 89 mm Hg), normal (SBP, 120 to 129 mm Hg or DBP, 80 to 84 mm Hg), and optimal (SBP < 120 mm Hg and DBP < 80 mm Hg). We also separately examined SBP, DBP, mean arterial pressure (MAP), and pulse pressure. Microalbuminuria was defined using sex-specific cutoff values (urine albumin-creatinine ratio > or = 17 and < or = 250 microg/mg [> or =1.0 and < or =28 mg/mmol] for men and > or = 25 and < or = 355 microg/mg for women [> or =3 and < or =40 mg/mmol]). We used multivariate logistic regression to analyze the association between different BP measurements and microalbuminuria.

Results: Compared with optimal BP, high-normal BP was significantly associated with increased odds of microalbuminuria (odds ratio [OR], 2.13; 95% confidence interval [CI], 1.51 to 3.01). Similarly, MAP (OR, 1.41; 95% CI, 1.15 to 1.74 per 10-mm Hg increment), SBP (OR, 1.27; 95% CI, 1.09 to 1.48 per 10-mm Hg increment), and DBP (OR, 1.29; 95% CI, 1.06 to 1.57 per 10-mm Hg increment) were significantly associated with microalbuminuria.

Conclusion: High-normal BP is significantly associated with microalbuminuria compared with optimal BP and may be a biomarker of the increased cardiovascular risk observed in this population.