Influence of HbA1c on short-term blood pressure variability in type 2 diabetic patients with diabetic nephropathy

The aim of this study was to understand the characteristics of blood pressure(BP)variability in subjects with diabetic nephropathy(DN),and identify the probable predictors affecting BP variability.Fifty-one chronic kidney disease(CKD)-hypertensive patients without diabetes(NDN group)and sixty type 2 diabetic patients with overt DN(DN group)were enrolled in this study.The values of short-term BP variability were obtained from 24 h ambulatory BP monitoring(ABPM).Variance analysis or nonparametric analysis revealed that 24-h systolic BP variability and nighttime systolic BP variability of the DN group were significantly higher than those of the NDN group[(12.23±3.66)vs.(10.74±3.83)mmHg,P<0.05;(11.23±4.82)vs.(9.48±3.69)mmHg,P<0.05].Then the patients of the DN group were divided into two groups according to glycated hemoglobin(HbA1c)level:Group A(HbA1c<7%)and Group B(HbA1c≥7%),and the t-test showed that patients in Group B had larger 24-h diastolic,daytime diastolic,and nighttime systolic/diastolic BP variability compared with Group A.In the DN group,partial correlation analysis revealed that HbA1c exhibited a strong association with 24-h diastolic,daytime diastolic,nighttime systolic and diastolic BP variability(P<0.001,P<0.001,P<0.05,and P<0.001,respectively).Taken together,larger short-term BP variability was detected in hypertensive type 2 diabetic patients with overt nephropathy and renal insufficiency.It may imply that the optimal BP variability level could benefit from a better glycaemic control.