Microalbuminuria in diabetic subjects with chronic peripheral neuropathy

Fifty-five patients with chronic peripheral neuropathy, 31 with and 24 without retinopathy, had albumin excretion rates determined on 2-h supine urine collections on three occasions by a radioimmunoassay method. Four patients with retinopathy had albustix-positive proteinuria and were excluded from subsequent analysis. Microalbuminuria was found in 20 of the 27 patients with retinopathy compared with 10 of the 24 patients with neuropathy alone. The mean albumin excretion rate (AER) was higher in neuropathic patients with retinopathy than in those patients with neuropathy alone (41.2 +/- 40.3 vs 18.8 +/- 33.2 micrograms/min, P less than 0.01). Multivariate analysis of the data was performed and this revealed a correlation coefficient of R2 = 0.33 (P less than 0.01) for AER as the dependent variable with respect to the independent variables HbA1, systolic blood pressure and known duration of diabetes. There was, however, no significant contribution separately of these individual variables to the regression equation. Microalbuminuria was significantly associated with retinopathy although almost half of the patients with neuropathy alone had microalbuminuria. The association between microalbuminuria and neuropathy even in the absence of retinopathy provides support for a microvascular element in the pathogenesis of diabetic neuropathy.