Cardiovascular autonomic function is associated with (micro-)albuminuria in elderly Caucasian sujects with impaired glucose tolerance or type 2 diabetes: the Hoorn Study

Abstract

Objective: To determine whether impaired cardiovascular autonomic function correlates with albuminuria in an age-, sex-, and glucose tolerance-stratified sample of an elderly (50-75 years of age) Caucasian population and to determine whether this association is independent of other determinants of albuminuria.

Research design and methods: We studied 536 subjects, 256 with normal glucose tolerance, 143 with impaired glucose tolerance (IGT), and 137 with type 2 diabetes. Microalbuminuria was defined as an albumin-to-creatinine ratio of > or =3.0 and < or =30 mg/mmol in an early morning urine sample. We used the deep-breathing test and the lying-to-standing test to obtain 4 measurements of cardiovascular autonomic function: 1) the heart rate (HR) variability during deep breathing, 2) the maximum HR within 15 s after standing up minus the mean HR before standing, 3) the maximum R-R interval between 15 and 30 s after standing up divided by the minimum R-R interval within 15 s after standing up, and 4) the systolic blood pressure in response to standing up. These 4 measurements were summarized in a single cardiovascular autonomic function score (CAFS).

Results: A total of 38 subjects with microalbuminuria and 3 subjects with macroalbuminuria (>30 mg/mmol) were grouped as having albuminuria. In bivariate analyses, albuminuria was associated with age, waist-to-hip ratio, systolic and diastolic blood pressure, calculated glomerular filtration rate, and glucose tolerance status. The mean CAFS was higher in subjects with versus without albuminuria (7.5 vs. 5.9, P<0.001). Multiple logistical regression analyses revealed that the CAFS was independently associated with albuminuria in subjects with IGT or type 2 diabetes with an odds ratio (95% CI) of 1.19 (1.02-1.39) per point increase in the CAFS.

Conclusions: Impaired cardiovascular autonomic function is independently associated with (and thus a possible contributor to) the presence of albuminuria in subjects with IGT or type 2 diabetes.