Autonomic Neuropathy Predicts Deterioration in Glomerular Filtration Rate in Patients With IDDM

Abstract

OBJECTIVE To evaluate whether autonomic neuropathy predicts deterioration in glomerular filtration rate in IDDM patients. RESEARCH DESIGN AND METHODS A prospective study in which 35 IDDM patients have been followed for 10–11 yr. Autonomic nerve function tests included heart-rate reactions to deep breathing (expiration-to-inspiration ratio) and to tilt (acceleration and brake indexes). GFR was evaluated by the 51Cr-EDTA plasma clearance method. RESULTS At entry to the study, no significant differences were noted in age (39 ± 2 [mean ± SE] vs. 42 ± 4 yr), duration of diabetes (20 ± 3 vs. 23 ± 4 yr), supine blood pressures (120/79 ± 3/2 mmHg vs. 121/78 ± 6/3 mmHg), and GFR (113 ± 6 vs. 107 ± 3 ml·min−1·1.73 m−2) between 20 patients with and 15 without autonomic neuropathy (age-corrected criteria). After 10–11 yr, GFR had decreased significantly (22 ± 4 ml·min−1·1.73 m−2 P < 0.001) in patients with autonomic neuropathy but not (8 ± 5 ml·min−1·1.73 m−2, NS) in patients without. In keeping with this, GFR decreased more than expected (difference in GFR/ expected decrease in GFR) in patients with autonomic neuropathy, compared with those without (4.46 ± 0.98 vs. 0.48 ± 0.73, P < 0.005). CONCLUSIONS Autonomic neuropathy predicts future deterioration in GFR in IDDM patients.