Nighttime hospital blood pressure--a predictor of death, ESRD, and decline in GFR

Abstract

Nighttime systolic blood pressure (BP) from ambulatory blood pressure monitoring (ABPM) is more predictive than clinic BP for cardiovascular disease, stroke, and death even after controlling for clinic BP. However, ABPM is expensive and burdensome to obtain regularly. BPs obtained in the hospital may provide a window into nighttime BP. We conducted a retrospective cohort study of all hypertensive patients admitted to the Louis Stokes Cleveland Department of Veterans Affairs Medical Center (LSCDVAMC) in 2002 and 2003 with one or more BP recorded between midnight and 6 am on the day of or the day before discharge. The mean age of the study population (n = 1085) was 62 years and 96% were male. Twenty-two percent had coronary artery disease (CAD) and 34% had diabetes. The mean nighttime systolic BP was 132 mmHg and baseline glomerular filtration rate (GFR) was 83 mL/min per 1.73 m(2). Over a median follow-up period of 4.3 years, 266 subjects died, 22 developed end-stage renal disease (ESRD), 99 had a 50% decline in GFR, and 136 developed myocardial infarction (MI). The adjusted hazard ratios (HRs) associated with a 10 mmHg increase in nighttime systolic BP were 1.03 (95% confidence interval, 0.93-1.15) for death, 1.30 (0.94-1.80) for ESRD, 1.26 (1.08-1.47) for a 50% decline in GFR, 1.07 (0.92-1.23) for myocardial infarction, and 1.12 (1.03-1.23) for a composite of death, ESRD, or a 50% decline in GFR. In conclusion, nighttime systolic BP in hospitalized patients is an independent predictor of important clinical outcomes such as a composite of death, ESRD, or a 50% decline in GFR.

Figure 1

Patients meeting inclusion and exclusion criteria.