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Tight glycemic control benefits questionable for microvascular, macrovascular complications

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August 24, 2016

Tight glycemic control confers no substantial benefit on the risk for microvascular or macrovascular complications, despite a consistent RR reduction for nonfatal myocardial infarction, according to a recent examination of meta-analyses, guidelines and randomized controlled trials.

“There is a widespread consensus about the value of tight glycemic control to prevent complications in patients with type 2 diabetes that needs to be recalibrated based on the available evidence,” Rene Rodriguez-Gutierrez, MD, MSc, of the knowledge and evaluation research unit in the division of endocrinology, diabetes, metabolism and nutrition at the Mayo Clinic in Rochester, Minnesota, told Endocrine Today. “The existing discordance may be distorting priorities in research and practice.”

Rene Rodriguez
Rene Rodriguez-Gutierrez

Rodriguez-Gutierrez and Victor M. Montori, MD, MSc, also at the Mayo Clinic, analyzed 16 guidelines and 328 statements addressing glycemic control published between 2006 and 2015, 11 meta-analyses published between 2009 and 2014 and five randomized controlled trials and their extension studies. Using GRADE, a system for determining the study quality, the researchers found that the evidence warranted moderate confidence in estimates. Results were inconsistent for the benefits of tight glycemic control on mortality outcomes, and evidence was “sparse” on the benefits of tight glycemic control for end-stage renal disease, renal death and amputations.

“Although no significant impact of tight glycemic control on the risks of patient-important nephropathy, retinopathy or neuropathy is evident, most published statements and practice guidelines endorse its value to prevent microvascular complications,” the researchers wrote. “It is possible that these statements rely on indirect evidence (ie, on surrogates of these patient-important outcomes, such as microalbuminuria), but such reliance should reduce their confidence in the value of glycemic control.”

The researchers found that tight glycemic control reduced the risk for nonfatal MI by 15% consistently across studies, although there was no effect found on all-cause and CVD mortality, strokes or amputations.

“Given our findings, we think it is an opportunity to get away from our still ‘glucocentric’ approach and embrace a patient-centered approach to diabetes care,” Rodriguez-Gutierrez said. “A care that values how the patient feels (quality of life), takes into consideration the burden of the different illnesses that coexist with diabetes and the consequent burden of treatment, rather than just lab numbers, eg, HbA1c, LDL cholesterol or blood pressure control.”

He said patients and clinicians should work together to determine the best glycemic targets and treatment regimen that fits into the patients’ lives.

“Embracing a skeptical view of tight glycemic control may, hopefully, spur research to discover new therapeutic approaches to prevent diabetes complications,” Rodriguez-Gutierrez said. – by Regina Schaffer

For more information:

Rene Rodriguez-Gutierrez, MD, MSc, can be reached at the Mayo Clinic, 1216 Second St. SW, Rochester, MN 55902; email: rodriguezgutierrez.rene@mayo.edu.

Disclosure: Rodriguez-Gutierrez and Montori report no relevant financial disclosures.