Associations Between Day-by-Day Home Blood Pressure Variability and Renal Function and Albuminuria in Patients With and Without Diabetes

BACKGROUND: The phenotype of diabetic kidney disease represents a lower estimated glomerular filtration rate (eGFR) and albuminuria. We investigated the association between day-by-day home blood pressure (BP) variability and the eGFR in subjects with diabetes and compared this association with that in subjects without diabetes. We then attempted to determine whether the association is present in albuminuria. METHODS: We analyzed 4,231 patients with risk factors of cardiovascular disease (24.4% with diabetes) from the J-HOP (Japan Morning Surge-Home Blood Pressure) study. Home BP was measured in the morning and evening for 14 days. We calculated the SD, coefficient of variation, average real variability (ARV), and variation independent of the mean of the subjects' morning and evening home systolic BP (SBP) as the indexes of day-by-day home BP variability. RESULTS: A multiple linear regression analysis adjusted for covariates showed both average morning and evening SBP were associated with the log-transformed urine albumin-to-creatinine ratio (UACR) with and without diabetes (all P < 0.05), but not with the eGFR except for an association of average evening SBP in the no-diabetes group. None of the indexes of day-by-day morning and evening home SBP variability were associated with the log-transformed UACR except for the association between the ARV of home morning SBP in the diabetes group. All of the indexes of day-by-day morning and evening home SBP variability were associated with the eGFR only in the diabetes group (all P < 0.05). CONCLUSIONS: The association between increased day-by-day home BP variability and impaired renal function was unique in diabetes.