Glycemic control worse over time in type 2 patients who decline insulin, study finds

In adults with uncontrolled type 2 diabetes who initially declined insulin versus those who initially accepted, median time to an HbA1c level below 7.0% was 50 months versus 38 months.

Patients with uncontrolled type 2 diabetes who decline insulin therapy have worse glycemic control over time than those who begin using insulin as recommended, according to a recent study.

Researchers performed a retrospective study of adults with type 2 diabetes and suboptimal glycemic control, defined as an HbA1c level of 7.0% or greater, for whom insulin therapy was recommended. Patients were treated at two U.S. academic hospitals between 2000 and 2014. Whether a patient declined recommended insulin therapy was determined via clinicians' notes, which were analyzed by natural language processing, a technology that rapidly extracts relevant clinical text using computational analysis. The primary outcome was time to reaching an HbA1c level below 7.0%. The results of the study, which was funded in part by a grant from Sanofi, were published Feb. 20 by Diabetic Medicine.

After individuals with estimated glomerular filtration rate less than 30 mL/min/1.73 m2 or without follow-up HbA1c measurements were excluded, a total of 5,307 participants were included in the study. Of these, 2,267 (42.7%) initially declined to receive insulin therapy. The median baseline HbA1c was 9.2%, and patients were followed for a median of 40.2 months (range, 0.07 to 179.3 months). After a median of nine months of follow-up, 49.5% of patients had an HbA1c level below 7.0%. Of the patients who initially declined insulin, 404 (17.8%) began it within a year, 158 (7.0%) began another noninsulin diabetes medication within a year, and 16 (0.7%) did both. Median time to HbA1c control was 50 months in those who initially declined insulin versus 38 months in those who initially accepted (P<0.001).

Multivariable analysis found that declining insulin therapy was significantly associated with longer time to HbA1c control (hazard ratio, 0.89; 95% CI, 0.82 to 0.97; P=0.008). Accepting recommendations for insulin therapy was more likely among patients with diabetes complications (odds ratio [OR], 1.32; 95% CI, 1.13 to 1.53; P<0.001) or a higher HbA1c level (OR, 1.10; 95% CI, 1.07 to 1.13; P<0.001) and less likely in patients who were older (OR, 0.81; 95% CI, 0.76 to 0.86; P<0.001) or who were taking more noninsulin medications for diabetes (OR, 0.78; 95% CI, 0.74 to 0.83; P<0.001).

The authors noted that they could not prove causal relationships and that some relevant information may have been missing, among other limitations, including that patients may have had different HbA1c treatment targets depending on their individual circumstances. They concluded that patients with uncontrolled type 2 diabetes often decline recommendations for insulin therapy and that declining insulin is associated with poor glycemic control. “Further investigation is needed to establish the optimal approach to discussion of treatment options with individuals with type 2 diabetes to ensure that individuals make fully informed choices while optimizing clinical outcomes,” the authors wrote.