Not all patients with type 2 diabetes are adherent to insulin therapy. A retrospective study analyzed patient factors that are predictive of declining insulin therapy and outcomes associated with doing so.
Adult patients with type 2 diabetes with suboptimal glycemic control were evaluated. Suboptimal glycemic control was defined as hemoglobin A1c (HbA1c) ≥53 mmol/mol (7.0%). Patients were identified after being recommended to insulin therapy at one of two academic hospitals between 2000 and 2014. Provider notes were used to determine which patients declined insulin therapy. The main outcome measure was time to HbA1c <53 mmol/mol (7.0%).
A total of 5,307 patients were recommended insulin therapy, of whom 2,267 (42.7%) declined. Patients who initiated insulin therapy had a shorter median time to HbA1c control compared with those who declined (38 months vs. 50 months; P<0.001).
Multivariable analysis found that patients who declined insulin therapy were less likely to achieve HbA1c (hazard ratio, 0.89; 95% confidence interval [CI], 0.82-0.97; P=0.008). Factors associated with initiating insulin therapy included having diabetes complications (odds ratio [OR], 1.32; 95% CI, 1.13-1.53; P<0.001) and a higher HbA1c (OR, 1.10; 95% CI, 1.07-1.13; P<0.001). Patients were less likely to start insulin therapy if they were older (OR, 0.81; 95% CI, 0.76-0.86; P<0.001) or taking other non-insulin diabetes medications.
“Individuals with uncontrolled type 2 diabetes who declined insulin therapy subsequently had worse glycemic control,” the authors concluded. “These findings highlight the need to improve our understanding of the relationship of this common but poorly explored clinical phenomenon to blood glucose control and ultimately diabetes complications.”