Design of controlled clinical trials for diabetic polyneuropathy.

Diabetic neuropathy is a common and debilitating complication of diabetes mellitus associated with high health costs. In recent years several clinical trials have been undertaken to test the efficacy of drug intervention in this disorder. The results of these trials have in general been disappointing. In this review we discuss selection criteria, efficacy endpoints, duration of clinical trials, and data collection and analyses. We offer suggestions based on past experiences that might improve trial design and execution in order to achieve improved results from treatment of this silent but common disorder.