Variable systolic blood pressure could be associated with nephropathy risk

Variations in systolic blood pressure could be associated with increased risk for diabetic nephropathy, according to a recent study.

Researchers in Kyoto, Japan, performed a retrospective cohort study of patients with type 2 diabetes who were treated as outpatients at a university clinic from April 2008 to September 2012. Systolic blood pressure was measured at each visit over one year, and coefficients of variation were calculated. The researchers then assessed changes in urinary albumin excretion or development of albuminuria over time and used multiple regression analysis and multiple Cox regression modeling to determine potential relationships between variability of systolic blood pressure and diabetic nephropathy. The study results were published online Jan. 22 by Diabetes Care.

A total of 354 consecutive patients with a mean age of 65.5 years were included in the study. The mean coefficient of variation of systolic blood pressure was 8.0% ± 4.0%, and average follow-up time was 3.76 ± 0.71 years. Blood pressure was measured an average of 7.19 times per patient during the initial study year. Two hundred eighteen patients had normoalbuminuria at baseline, and 28 patients developed albuminuria during the study period. In multiple regression analysis, an independent association was seen between the coefficient of variation of systolic blood pressure and change in urinary albumin excretion (β=0.1758; P=0.0108). In adjusted Cox regression analyses, average systolic blood pressure, coefficient of variation of systolic blood pressure, total cholesterol, and logarithm of triglycerides were each associated with an increased risk for albuminuria (hazard ratios, 1.047, 1.143, 1.024 and 18.40, respectively).

The authors acknowledged that all of the study patients were Japanese and that their results may not be generalizable to other settings. They also noted that variation in blood pressure may have been due to medications and that the study was small, among other limitations. However, they concluded that visit-to-visit variability in systolic blood pressure could indicate risk for nephropathy progression or albuminuria in patients with type 2 diabetes, and that the role of this variability should be clarified.