Association of Blood Pressure at Specific Time-Points with 1-Year Renal Outcomes in Patients with Diabetic Chronic Kidney Disease

BACKGROUND: The 24-hour mean blood pressure (mBP) is the best predictor of organ damage; however, it is not easily applicable in clinical practice. The APrODiTe study suggested that systolic blood pressure (SBP) values at 7:00 AM and 9:30 PM were associated with the 24-hour mSBP in patients with chronic kidney disease (CKD). We investigated the association of the SBP values at these time-points with the renal outcomes in patients with diabetic CKD during 1-year follow-up. METHODS: Ninety-six patients with diabetic CKD were included at 1-year follow-up. The renal outcomes were an increase in the random urine protein/creatinine ratio or estimated glomerular filtration rate (eGFR) deterioration, which means a decrease in eGFR ≥5 mL/min/1.73 m(2) compared to the baseline values. RESULTS: The baseline SBP values at 7:00 AM, and 9:30 PM, and the 24-hour mSBP were 135.6±24.9 mmHg, 141.7±25.6 mmHg, and 136.4±20.7 mmHg, respectively. The SBP values measured at the same time-points after 1 year were similar to those at baseline. The SBP at 7:00 AM was significantly associated with eGFR deterioration in the univariate and multivariate analyses (odds ratio [OR]: 1.032; 95% confidence interval [CI]: 1.006–1.059; p=0.016). The SBP at 7:00AM and 24-hour mSBP did not show a concordant association with sustained proteinuria in the linear and logistic analyses. In the subgroup analysis, the association between the SBP at 7:00 AM and eGFR deterioration persisted in patients with CKD stage 3–5 (OR: 1.041; 95% CI: 1.010–1.073; p=0.010). CONCLUSION: The SBP at 7:00 AM, in addition to the 24-hour mSBP, is also associated with eGFR deterioration in patients with diabetic CKD, particularly in those with CKD stage 3–5.