Comparative prognostic role of nighttime blood pressure and nondipping profile on renal outcomes

Different studies have addressed the predictive role of nighttime hemodynamics on cardiovascular and renal outcomes, although nocturnal blood pressure (BP) phenotypes (i.e. nondipping pattern and absolute nocturnal BP) have been found to be predictive of worse health outcomes. Furthermore, differences in both examined populations - ranging from healthy and younger subjects to those with overt cardiovascular disease - and study design (i.e. cross-sectional or longitudinal) make the interpretation of the suggested correlations difficult. Focusing on the kidney, we reviewed the literature addressing the impact of nocturnal BP phenotypes on renal outcomes in different populations by further dividing our search by study design. The evidence so far qualifies absolute nocturnal BP as a better predictor or determinant of kidney dysfunction as compared with the nondipping status. The magnitude of nocturnal hemodynamic load imposed at the glomerular level might be of higher prognostic value as compared with the integration of the pathophysiological mechanisms associated with impaired nocturnal BP variability. These findings underline the importance of nocturnal BP phenotypes, retrieved by ambulatory BP measurements, on age-dependent progressive kidney function decline and question whether, to what extent and in whom the reduced nocturnal BP or reverse nondipping BP profile to a normal pattern will be of benefit.