Perirenal Fat Thickness Is Associated With Disturbed Circadian Blood Pressure Rhythm in Essential Hypertension

Circadian blood pressure (BP) rhythm disturbances predict cardiovascular risk. Perirenal fat thickness (PRFT) may influence blood pressure regulation, but its role in key circadian phenotypes remains unclear. We examined whether PRFT is associated with disturbances in circadian BP rhythm and short-term blood pressure variability (BPV) in patients with essential hypertension, independently of traditional adiposity indices. In this cross-sectional study of 253 patients, PRFT and other adiposity indices were measured by abdominal CT. Circadian BP rhythm and variability were assessed via 24-hour ambulatory blood pressure monitoring (ABPM). Patients were stratified into PRFT tertiles for analysis. The high PRFT group (Tertile 3) exhibited a significantly higher prevalence of morning hypertension (68.7% vs. 40.0%), nocturnal hypertension (88.0% vs. 63.5%), and a reverse-dipper pattern (20.5% vs. 7.1%) compared to the low PRFT group (Tertile 1) (all p < 0.05). After adjustment for multiple confounders, each 1-mm increase in PRFT remained independently associated with a 10.2%, 15.2%, and 9.9% increased risk of morning hypertension, nocturnal hypertension, and reverse-dipper pattern, respectively. In contrast, traditional adiposity indices (BMI, VFA, TFA) showed no independent associations. PRFT demonstrated the best discriminative performance for nocturnal hypertension (AUC = 0.685) among all fat indices, with the AUC improving to 0.720 upon inclusion of age. No significant association was observed between PRFT and short-term BPV. PRFT is independently associated with disturbed circadian BP rhythm beyond general and visceral adiposity. As a quantifiable CT biomarker, PRFT shows potential clinical utility for assessing high-risk BP rhythm phenotypes.