Quality assessment of randomized clinical trials on medical treatment of diabetic neuropathy

The aim of this study was to critically assess the literature concerned with medical treatment for the prevention of the deterioration of nerve function in diabetic patients. The analysis of 38 randomised clinical trials (RCTs) has shown that most of the studies suffer from serious methodological drawbacks; the methods of randomisation were unspecified in 95% of the RCTs, in one-third of the studies more than 15% of the patients were excluded from the analysis; 95% of the studies failed to provide evidence of having estimated the sample size needed to detect a pre-specified treatment difference. In addition to presenting an unsatisfactory picture regarding methodological quality, the results of the examined trials are seriously limited by their dubious clinical relevance: only 2 trials (5%) observed a clinically relevant outcome. Furthermore, the short length of follow-up does not allow the detection of important changes in the main outcomes investigated.