Abstract
Background
Although abnormal blood pressure patterns are associated with adverse cardiorenal outcomes, their associations are yet unquantified by nocturnal dipping status. We examined the association of nocturnal blood pressure dipping pattern with albuminuria and kidney function among participants with controlled hypertension without prior advanced kidney disease.
Methods
Ambulatory blood pressure measurements were collected from 995 middle-aged, cardiology clinic patients with controlled office blood pressure (<140/90 mmHg). The magnitude of dipping was calculated as the difference between daytime and nighttime systolic blood pressure divided by daytime systolic blood pressure. Accordingly, the participants were categorized as extreme-dipper (≥20%), dipper (10-<20%), non-dipper (0-<10%), or reverse-dipper (<0%). We analyzed the cross-sectional associations of dipping with albuminuria (urine albumin-to-creatinine ratio ≥30 mg/g) and decreased estimated glomerular filtration rate (<60 ml/min/1.73m 2), adjusting for office/ambulatory blood pressure, antihypertensive class, body mass index, total cholesterol, fasting glucose, socioeconomic status, and health behavior.
Results
The participants (mean age 60.2 years; 52.9% male) consisted of 13.5% extreme-dippers, 43.1% dippers, 34.7% non-dippers, and 8.7% reverse-dippers. In reference to dippers, odds ratios [95% confidence interval] for albuminuria were 1.73 [1.04-2.60] in reverse-dippers, 1.67 [1.20-2.32] in non-dippers, and 0.62 [0.38-1.04] in extreme-dippers. Likewise, abnormal dipping profile was associated with decreased kidney function: reverse-dipping, 2.02 [1.06-3.84]; non-dipping, 1.98 [1.07-3.08]; extreme-dipping, 0.69 [0.20-1.17]. The associations persisted participants with more conservatively controlled office blood pressure (<130/80 mmHg).
Conclusions
Monitoring diurnal and nocturnal blood pressure may identify chronic kidney disease otherwise overlooked based on office blood pressure.