Masked hypertension and kidney function decline

Background Hypertension diagnosed by blood pressure (BP) measured in the clinic is associated with rapid kidney function decline (RKFD) and incident chronic kidney disease (CKD). The extent to which hypertension defined using out-of-clinic BP measurements is associated with these outcomes is unclear. Methods We evaluated the association of any masked hypertension (daytime SBP/DBP ≥ 135/85 mmHg, night-time SBP/DBP ≥ 120/70 mmHg or 24-h SBP/DBP ≥ 130/80 mmHg) with RKFD and incident CKD among 676 African-Americans in the Jackson Heart Study with clinic-measured SBP/DBP less than 140/90 mmHg who completed ambulatory BP monitoring in 2000-2004. RKFD was defined as a decline in estimated glomerular filtration rate (eGFR) at least 30% and incident CKD was defined as development of eGFR less than 60 ml/min per 1.73 m with an at least 25% decline in eGFR between 2000-2004 and 2009-2013. Results The mean age of participants was 57.6 years, 28.8% were men and 52.7% had any masked hypertension. After a median follow-up of 8 years, 13.8 and 8.6% of participants had RKFD and incident CKD, respectively. In unadjusted analyses, masked hypertension was associated with an increased odds for incident CKD [odds ratio (OR) 2.20, 95% confidence interval (CI) 1.22, 3.97]. This association remained statistically significant after adjustment for demographic characteristics, baseline eGFR and albumin-to-creatinine ratio (OR 1.95, 95% CI 1.04, 3.67) but was eliminated after propensity score adjustment (OR 1.62, 95% CI 0.87, 3.00). There was no association between masked hypertension and RKFD. Conclusion Masked hypertension may be associated with the development of CKD in African-Americans.