Systolic Blood Pressure Rhythm Is a Protective Predictor of eGFR in Older Hypertensive Men

Background: It is recognized that blood pressure (BP) follows a circadian rhythm, exhibits two peaks during 24 hours. But it is uncertain whether BP has 12 hours rhythm and the influence of this rhythm. Methods: A total of 200 older hypertensive males without overt cardiovascular or cerebrovascular diseases were recruited in the longitudinal study. 12 patients had less than 20 ambulatory blood pressure readings during 24 hours. Therefore, a total of 188 patients were included in the analyses. The 12 hours circadian rhythmicity of blood pressure was analyzed by ARSER. Blood pressure with 12h rhythmicity was selected by P < 0.05. Estimated glomerular filtration rate (eGFR) was calculated using the CKD-EPI formula. The primary outcome was the change of eGFR. Results: The average age was 64.9±7.2 years, and the eGFR was 83.5±14.7 mL/min/1.73m2. 17 patients had 12 hours rhythmicity in both Systolic blood pressure (SBP) and diastolic blood pressure (DBP). 128 patients had arrhythmicity in either SBP or DBP. At a mean follow-up period of 3 (2.5–3.7) years, 16 patients died, 33 patients were lost to follow-up. The mean eGFR in baseline and follow-up time was 86.4±14.2 and 81.7±16.1 mL/min/1.73m2 (P=0.010). There was no significant difference in the level of urinary protein and creatinine ratio (7.5(3.8-19.4) vs 8.3(7.0-12.7) mg/g, P=0.059). Compared to participants in rhythmic SBP group, the other group had more eGFR decline(P=0.005). But the change of eGFR was similar between DBP rhythmicity group and arrhythmicity group. We defined eGFR decline as the falling difference over 1/2 SD between follow-up and baseline. The risk of eGFR decline in patients with arrhythmic SBP was third that of rhythmic rhythm SBP group after adjusting for confounding factors including age, smoke, alcohol, DM，BMI and albumin(HR = 3.005(1.122-8.048), P=0.029). Conclusion: The rhythm of systolic blood pressure is a protective predictor of eGFR in older hypertensive males. We need to focus on the rhythm pattern of BP. Funding: Government Support – Non-U.S.