Characteristics Associated with Masked Nocturnal Hypertension in Patients with Chronic Kidney Disease

Background: Hypertension is common in chronic kidney disease (CKD) and uncontrolled hypertension leads to accelerated decline in kidney function. Since treatment decisions rely largely on daytime clinic or home BP measurements, patients with controlled daytime but uncontrolled nighttime BP (masked nocturnal hypertension, MNH) are often clinically unrecognized and not distinguished from hypertensive patients that have both controlled daytime and controlled nighttime BP. Although CDUN can only be detected through 24-hour ambulatory BP monitoring (ABPM), this assessment is critical, as nocturnal BP is a stronger predictor of cardiovascular risk than daytime measurements. We therefore investigated the prevalence, clinical characteristics, and physiological determinants of MNH in CKD. We hypothesized that individuals with masked nocturnal hypertension would exhibit impaired autonomic nervous system function and greater renal dysfunction compared with those with controlled nocturnal blood pressure. Methods: Fifty-eight adults with CKD Stages II–IV (mean age 64 ± 9 years, 60% Black, 26% female) and treated hypertension were enrolled. All participants underwent ABPM, and only those with controlled daytime BP per ABPM (mean daytime BP120/70 mmHg versus controlled BP if mean nighttime BP was < 120/70 mm Hg. Autonomic function was assessed via muscle sympathetic nerve activity (MSNA) by microneurography, baroreflex sensitivity (BRS), beat-to-beat BP variability (BPV), and heart rate variability (HRV). Vascular function was measured using pulse wave velocity (PWV) and reactive hyperemia index (RHI). Fluid status was evaluated via bioimpedance spectroscopy. Results: MNH prevalence was 38%. Compared to individuals with controlled BP, those with MNH had higher office and ambulatory BP, lower eGFR (p = 0.05), and elevated albumin-to-creatinine ratio (p = 0.033). MNH participants also exhibited higher extracellular-to-total body water ratio (p = 0.037) and more frequent non-dipping BP patterns (p < 0.001). MSNA, BRS, BPV, and HRV did not differ significantly between groups. Vascular function was comparable between groups. Conclusion: MNH is highly prevalent in CKD and strongly linked to renal dysfunction and volume overload. These findings underscore the importance of ABPM and targeted BP control to mitigate CKD progression and cardiovascular risk. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.