Cardiovascular Autonomic Function Is Associated With (Micro-)Albuminuria in Elderly Caucasian Subjects With Impaired Glucose Tolerance or Type 2 Diabetes

The Hoorn Study

Smulders, Yvo M. MD
Jager, Agnes MD
Gerritsen, Jeanet MD
Dekker, Jacqueline M. PHD
Nijpels, Giel MD
Heine, Robert J. MD
Bouter, Lex M. PHD
Stehouwer, Coen D.A. MD

From the Department of Internal Medicine (Y.M.S.), Academic Medical Center, Amsterdam; and the Institute for Research in Extramural Medicine (A.J., J.G., J.M.D., G.N., R.J.H., L.M.B., C.D.A.S.), the Department of Clinical Physics and Informatics (J.G.), the Department of Internal Medicine (R.J.H., C.D.A.S.), and the Department of Epidemiology and Biostatistics (L.M.B.), Vrije Universiteit, Amsterdam, the Netherlands.

Address correspondence and reprint requests to Yvo M. Smulders, MD, Department of Internal Medicine, Academic Medical Center, Meibergdreef 9, Amsterdam, 1105 AZ, the Netherlands. E-mail: [email protected].

Received for publication 14 January 2000 and accepted in revised form 24 May 2000.

Abbreviations: CAFS, cardiovascular autonomic function score; CVD&D, cardiovascular disease and/or drugs; EIHR_diff, the difference between intrabreath maximum and minimum heart rate averaged over 6 breaths; HR, heart rate; IGT, impaired glucose tolerance; L→SΔBP_sys, systolic blood pressure after standing up minus the supine systolic blood pressure; L→SΔHR_max, maximum heart rate within 15 s after standing up minus the mean heart rate during 1 min before standing; L→S_{max/min ratio}, 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; NGT, normal glucose tolerance.

A table elsewhere in this issue shows conventional and Système International (SI) units and conversion factors for many substances.

Diabetes Care 23(9):p 1369-1374, September 2000.

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 ≥3.0 and ≤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.