Abstract 9837: A Blunted Nocturnal Blood Pressure Decline is Associated with Total and Cardiovascular Mortality

Abstract

Introduction: A blunted nocturnal BP decline is associated with an increased cardiovascular risk. Nevertheless, patients with a blunted BP dip usually have high levels of nighttime BP, being both parameters clearly related. Thus, it is unclear if an abnormal dipping is deleterious per se or it merely reflects an elevated BP during sleep. Hypothesis: We aimed to assess the prognostic value of nocturnal BP decline, independently of the presence or not of nocturnal BP elevation. Methods: Vital status and death due to cardiovascular causes were obtained from death certificates in 59110 hypertensives, enrolled in the Spanish ABPM Registry between 2004 and 2014, and having a valid 24-h ABPM at entry. On the basis of BP data, patients were classified into 4 groups: Normal (<120 mmHg) night systolic BP (SBP) and normal (<0.9) systolic night-to-day ratio (NDR). Normal night SBP with elevated (≥0.9) NDR. Elevated (≥120 mmHg) night SBP with normal NDR and both elevated night SBP and NDR. Association between NDR, dipping status and groups combining night SBP and NDR with total and cardiovascular mortality were assessed by Cox models, adjusted for clinical confounders. Results: The total number of deaths were 2866 (978 of cardiovascular causes) during a median follow-up of 5 years. NDR predicted total mortality (HR for 1 SD change: 1.19; 95%CI: 1.15-1.23). Both patients with reduced dipping (HR: 1.28; 1.17-1.41) and risers (HR: 1.59; 1.42-1.77) had increased risk of total mortality, whereas extreme dippers (NDR<0.8) did not. With respect to patients with both normal night SBP and NDR, those with elevated NDR in the absence of elevated night SBP had increased risk of death (HR: 1.36; 1.19-1.55), as well as those with elevated night SBP and normal NDR (HR; 1.40; 1.21-1.62). Those combining both abnormalities had the highest risk (HR: 1.78; 1.60-1.98). Similar results were obtained for cardiovascular mortality. Conclusions: Abnormalities in the circadian dipping pattern are responsible for an increased risk of mortality, both total and cardiovascular. Increased mortality rates are observed in patients with a reduced nocturnal dip and, even more intensively, in those with a riser pattern. This abnormal dipping increases the risk of mortality even in the absence of BP elevation.