Efficacy of Periodic Intensive Insulin Therapy on secondary complications of diabetes warrants larger prospective randomized clinical trials.

The authors respond:

We acknowledge and agree with the general criticism of all observational studies put forth by Drs Chang and Philis-Tsimikas. The article in question was a review of several dozen articles published after patients were exposed to this type of therapy and its potential benefits to those patients who experience the progressive effects of diabetes.

In regard to our conclusions, accumulation of like results from like studies (albeit observational studies) with consistent results relative to direction and magnitude of response over decades suggest a likely therapeutic effect. The design of these retrospective studies prohibits conclusion of efficacy, but the therapy appears promising in the otherwise potentially debilitating condition of diabetic peripheral neuropathy. Our article attempts to summarize data for physicians who may consider use of insulin in this manner in cases where the treating physician determines medical necessity.

This therapy requires further focused research and better understanding of the mechanism involved in the results being observed, such as a prospective randomized trial of both primary and secondary complications of diabetes that affect so many people in the world.