An A1C value today has consequences for outcomes tomorrow. That’s the message John M. Lachin, ScD, will deliver during the Saturday morning symposium The “Legacy Effect” in Diabetes—Are There Long-Term Benefits of Short-Term Tight Glycemic Management? The two-hour session begins at 8:00 a.m. CT Saturday, June 13.
“The basic idea is that if you have two subjects—one has an average A1C of 9% and the other an A1C of 7%, and then after 10 years they both have an A1C of 8% for the rest of their lives—the subject who had that initial period with a lower glucose level is going to continue to have a lower risk long-term than the subject who did not have early implementation of good control,” explained Dr. Lachin, Research Professor of Biostatistics and Bioinformatics, and of Statistics at George Washington University.
Whenever the level of glucose control can be improved, it should be done with the expectation that it will have long-term benefits, Dr. Lachin explained. Early implementation of intensive therapy or early improvements in glucose control will have long-term beneficial outcomes.
“It may take five to 10 years to see those effects, but it needs to be thought of in terms of what are the benefits I could accrue 10 years from now if I improve therapy now versus not improving therapy now,” he said. “In the latter case, you’re just going to get worse exponentially.”
Evidence for this approach goes back to the Diabetes Control and Complications Trial (DCCT). Subjects assigned to the intensive therapy group initially had essentially the same risk of progression of diabetes complications as the subjects assigned to the conventional group, but markedly reduced risk of complications over time.
“It took four years for the lower A1C in the intensive group to override the effects of the prior years of hyperglycemia that these subjects experienced before they entered the DCCT,” said Dr. Lachin, who will highlight studies suggesting that the formation of glycation end products may be the biological cause of these long-term outcomes.
After the conclusion of the DCCT, all of the subjects had annual exams as part of the Epidemiology of Diabetes Interventions and Complications (EDIC) study. EDIC researchers observed that the subjects who had been treated intensively continued to have a much lower risk of progression of diabetes complications than the subjects who had been treated conventionally, even though by that time the A1C levels in the two groups were no longer different.
“What all of this suggests is that if your A1C is 10 tomorrow, that 10 is going to have consequences beyond that,” Dr. Lachin said. “It’s not that there is what might be called glucotoxicity. It’s not the glucose itself that is the causal agent, but it’s the mechanism that’s triggered by the A1C.”
The symposium, chaired by Elizabeth Selvin, PhD, PPH, of Johns Hopkins Bloomberg School of Public Health, will feature three additional speakers. Rury R. Holman, FRCP, FMedSci, of the University of Oxford, will present “The Legacy Effect in Type 2 Diabetes.” William C. Knowler, MD, DrPH, of the National Institute of Diabetes and Digestive and Kidney Diseases, will present “The Legacy Effect of Lifestyle Intervention on Diabetes-Related Morbidity and Mortality.” Neda Laiteerapong, MD, MS, FACP, of the University of Chicago, will present “Lack of a Legacy Effect in Modern Glucose-Lowering Trials.”