"We wanted to find out if there was a way to take advantage of the benefits of glycemic control while avoiding increased mortality," Doria explained.
Doria and the research team compared standard glycemic control to intensive glycemic control, and they found very inconsistent results. The intensive glycemic control reduced the risk of myocardial infarction and other major cardiovascular events, but it was also associated with an increase in mortality from heart problems. They continued with genome-wide association studies (GWAS) to make sense of the discrepancies.
The GWAS results identified two genetic markers that seemed to be responsible in some way for a threefold increase in heart disease for individuals from the study receiving intensive glycemic control compared to those receiving standard care. The finding of these genetic markers is the first time predictors of death from heart disease have been associated with intensive glycemic control.
Next, the researchers used the markers to create a genetic risk score to understand further how study participants would respond to intensive glycemic control:
- Twenty percent of the participants had a “low” score, meaning they would receive the greatest benefit from intensive glycemic control, with a reduction in both fatal and nonfatal cardiovascular events
- Fifty percent had an “intermediate” score, meaning there would be a reduction in nonfatal events but not in fatal events
- Thirty percent had the highest score, meaning they would only experience negative effects, an increase in cardiovascular deaths and no decrease in nonfatal events
With more study and clarification, further understanding of the genetic risk score could help doctors identify patients most likely to benefit from intensive glycemic control with improved cardiac complications and those where the risk is greater than any possible benefit.
Sources: Joslin Diabetes Center