Cardiovascular autonomic function is associated with (micro-)albuminuria in elderly Caucasian subjects with impaired glucose tolerance or type 2 diabetes - The Hoorn study

OBJECTIVE - To determine whether impaired cardiovascular autonomic function correlates with albuminuria in an age-, sex-, and glucose tolerance-strati fied 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 gluc ose tolerance, 143 with impaired glucose tolerance (IGT), and 137 with type 2 diabetes. Microalbuminuria was defined as an albumin-to-creatinine ratio of greater than or equal to 3.0 and less than or equal to 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 funct ion: 1) the heart rate (HR) variability during deep breathing, 2) the maxim um HR within 15 s after standing up minus the mean HR before standing, 3) t he maximum R-R interval between 15 and 30 s after standing up divided by th e minimum R-R interval within 15 s after standing up, and 4) the systolic b lood pressure in response to standing up. These 4 measurements were summari zed 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 bivar iate analyses, albuminuria was associated with age, waist-to-hip ratio, sys tolic and diastolic blood pressure, calculated glomerular filtration rate, and glucose tolerance status. The mean CAFS was higher in subjects with ver sus without albuminuria (7.5 vs. 5.9, P < 0.001). Multiple logistical regre ssion analyses revealed that the CAFS was independently associated with alb uminuria 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 a ssociated with land thus a possible contributor to) the presence of albumin uria in subjects with IGT or type 2 diabetes.