Refinement of Evidence Base for Glucose Control

The danger of guidelines is revealed again in a recent study published in the New England Journal of Medicine regarding how tightly glucose levels should be controlled for diabetes patients.  (NEJM Article)  As we should all know by now in regard to medicine, the science is rarely settled, therefore, giving clinicians discretion is important.  There has been a long-standing debate about to what level glucose should be controlled.  This article reports the 6 year follow-up data in regard to trial arms using blood pressure lowering and tight glucose control among type 2 diabetes patients.  The primary outcomes in the trial were death from any cause and macrovascular events.  The results of this trial were the opposite of those from earlier studies.  Over 11,000 patients 55 years or older from 20 countries were originally enrolled between 2001 and 2003.  A large percentage of these patients participated in the long-term follow-up which is part of the current article.  The difference in blood pressure level which was present in the intervention group compared to placebo group during the main trial, was no longer present 6 months after the trial.  The difference in glycated hemoglobin levels had also disappeared.  The risk of death remained lower, although attenuated, in the follow-up period for those in the blood pressure treatment group, but not the glucose control intervention arm.  There was no ongoing reduced risk of macrovascular events for either intervention group.  The results suggest two things, one  is that ongoing treatment for blood pressure control is important to maintain its benefits; the second is that intensive glucose control is questionable as a strategy.  But most importantly, the divergent results from this and other trials suggest that the state of the art for best-quality diabetes care is yet uncertain, and guidelines therefore must be imperfect measures of quality.  Our guideline-happy culture needs to dial it back a bit, and realize the risks to patients, and the unfairness to clinicians, of insisting that certain care processes be followed for all patients.  The science is not that definitive and policymakers must be attuned to that fact.