Abstract P208: Raas And Markers Of Renal Function In Response To Sleep Hygiene Interventions

Introduction: Recent epidemiologic studies report that shorter sleep duration is associated with a rapid decline in renal function. This project investigated the effects of 8 weeks of sleep hygiene interventions on the renin-angiotensin-aldosterone system (RAAS) regulation and markers of renal function. Accumulating evidence suggests that sleep plays an important role in blood pressure (BP) regulation. While BP is influenced by renal function, it is not known if improving sleep hygiene may support regulation of the RAAS. Methods: Fifty participants (59.8 ± 1.5 years; 31 women) completed 3 overnight in-hospital stays: baseline (S1), pre-intervention (S2) following a 4-week wait-list evaluation phase from S1 and post-intervention (S3). During S2, participants with elevated BP (BP>120/80 to <160/100) were randomly assigned to two sleep hygiene conditions where in both conditions, the sleep period was stabilized, but in one it was also lengthened. As the study is still ongoing, we remain blind to which condition participants were randomized to. Morning and evening plasma renin activity (PRA), urinary albumin, creatinine, and serum cystatin C levels were measured from all three stays. Albumin-to-creatinine ratio (ACR) and estimated glomerulus filtration rate (eGFR) were calculated. Results: There was a significant decrease of night PRA at post-intervention (S3) compared to S2 (p<0.05) and S1 (p<0.05). However, morning PRA did not show any changes throughout the stays (p=0.3). The urinary ACR obtained from evening urine samples did not show significant changes (p=0.66). In addition, serum cystatin C levels measured from evening blood draws and the eGFR did not show significant changes (p=0.21 and p=0.18, respectively). Conclusion: The sleep hygiene approach to improving sleep was associated with blunted PRA levels in the evening. When unblinded we will report on whether increasing the sleep period was more effective than stabilizing circadian placement of sleep, alone.