Intensive Treatment Results Varies According to A1c

Ancillary study conducted using ACCORD data…

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James M. Hempe, Ph.D., from the Louisiana State University Health Sciences Center in New Orleans, and colleagues conducted an ancillary study using data from the Action to Control Cardiovascular Risk in Diabetes randomized trial involving 10,251 patients with type 2 diabetes. Participants were randomized to standard or intensive treatment, with HbA1c goals of 7.0 to 7.9 percent and less than 6 percent, respectively. The effect of intensive treatment on outcomes was assessed in patients with low, moderate, and high HGI.

The researchers found that the primary outcomes (composite of cardiovascular events) were improved with intensive treatment in the low (hazard ratio [HR], 0.75; 95 percent confidence interval [CI], 0.59 to 0.95) and moderate (HR, 0.77; 95 percent CI, 0.61 to 0.97) HGI subgroups, but not in the high HGI subgroup (HR, 1.14; 95 percent CI, 0.93 to 1.40). Only the high HGI subgroup had higher total mortality in intensively treated patients (HR, 1.41; 95 percent CI, 1.10 to 1.80). In standard and intensive treatment groups, high HGI correlated with increased risk of hypoglycemia.

The study tested the hypothesis that intensive treatment in the Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial disproportionately produced adverse outcomes in patients with diabetes with a high hemoglobin glycation index (HGI = observed HbA1c − predicted HbA1c).

ACCORD was a randomized controlled trial of 10,251 patients with type 2 diabetes assigned to standard or intensive treatment with HbA1c goals of 7.0% to 7.9% (53 to 63 mmol/mol) and less than 6% (42 mmol/mol), respectively. In this ancillary study, a linear regression equation (HbA1c = 0.009 × fasting plasma glucose [FPG] [mg/dL] + 6.8) was derived from 1,000 randomly extracted participants at baseline. Baseline FPG values were used to calculate predicted HbA1c and HGI for the remaining 9,125 participants. Kaplan-Meier and Cox regression were used to assess the effects of intensive treatment on outcomes in patients with a low, moderate, or high HGI.

The results showed that intensive treatment was associated with improved primary outcomes (composite of cardiovascular events) in the low (hazard ratio [HR] 0.75 [95% CI 0.59–0.95]) and moderate (HR 0.77 [95% CI 0.61–0.97]) HGI subgroups but not in the high HGI subgroup (HR 1.14 [95% CI 0.93–1.40]). Higher total mortality in intensively treated patients was confined to the high HGI subgroup (HR 1.41 [95% CI 1.10–1.80]). A high HGI was associated with a greater risk for hypoglycemia in the standard and intensive treatment groups.

From the results, HGI calculated at baseline identified subpopulations in ACCORD with harms or benefits from intensive glycemic control. HbA1c is not a one-size-fits-all indicator of blood glucose control, and taking this into account when making management decisions could improve diabetes care.

Practice Pearls:

• Only the high HGI subgroup had higher total mortality in intensively treated patients.
• HbA1c is not a one-size-fits-all indicator of blood glucose control, and taking this into account when making management decisions could improve diabetes care.
• The results showed that intensive treatment was associated with improved primary outcomes in the and moderate HGI subgroups but not in the high HGI subgroup.

James M. Hempe. The Hemoglobin Glycation Index Identifies Subpopulations With Harms or Benefits From Intensive Treatment in the ACCORD Trial. Published online before print April 17, 2015, doi: 10.2337/dc14-1844. Diabetes Care April 17, 2015 https://care.diabetesjournals.org/content/early/2015/03/02/dc14-1844.abstract