The sorbinil retinopathy trial: neuropathy results. Sorbinil Retinopathy Trial Research Group

We randomized 497 patients, aged 18 to 56 years with insulin-dependent diabetes mellitus for 1 to 15 years' duration, to treatment with sorbinil, an aldose reductase inhibitor, or to a placebo. Nearly 30% of patients showed worsening of clinical measures of distal symmetric polyneuropathy at maximum follow-up, with very little difference in rates in the two groups. We studied nerve conduction in 192 patients. For the median motor, median sensory, and peroneal nerves, there were no benefits in maximum amplitudes over the follow-up period. For the median motor and median sensory nerves, changes in velocities were not significantly different in the two randomized treatment groups. For the peroneal nerve, at the 30-month and maximum follow-up visits, the distribution of changes in nerve conduction velocity showed an overall improvement in the sorbinil group and a decline in the placebo group. The difference in distributions was statistically significant. Overall, we found no evidence that the early clinical signs and symptoms of diabetic neuropathy were altered by sorbinil.