Sociodemographic, clinical factors may influence insulin initiation in type 2 diabetes

The researchers found an inverse association between insulin initiation and age, and black and Hispanic participants were less likely to have insulin initiated compared with white participants.

Initiation of insulin in patients with type 2 diabetes may be affected by patient age, race or ethnicity, and diabetes complications, a recent study indicated.

Researchers performed a retrospective analysis of participants in the Look AHEAD (Action for Health in Diabetes) trial to identify factors that independently predicted insulin initiation in type 2 diabetes. Look AHEAD included ambulatory U.S. adults with type 2 diabetes who were overweight or obese and had a primary care clinician. In the current study, Cox proportional hazards models were used to estimate the association between patient characteristics and time to initiation of insulin. In addition, time-varying adjustment was performed for HbA1c over the 10 years of the study and for various clinical and socioeconomic factors. Study results were published online Jan. 19 by the Journal of General Internal Medicine.

The current study included 3,913 participants from Look AHEAD who were not using insulin at baseline. Mean age was 58.9 years, 58.8% were women, and 67.9% were white. Mean HbA1c level was 7.1%; mean diabetes duration was 5.5 years. Over a median follow-up of 8.0 years, 1,087 participants (27.8%) initiated insulin therapy. The researchers found an inverse association between insulin initiation and age (adjusted hazard ratio, 0.88 per 10 years; P=0.025). Patients with more diabetes complications were at higher risk for insulin initiation (P<0.001 for trend), and body mass index, smoking status, chronic kidney disease, cardiovascular disease, and family history of diabetes were independently associated with insulin initiation. Black and Hispanic participants had a lower risk for insulin initiation compared with white participants (adjusted hazard ratios, 0.77 [P=0.008] and 0.66 [P<0.001], respectively). No association was seen between insulin initiation and socioeconomic variables.

The researchers noted that they could not distinguish between clinician and patient preference in the decision to initiate insulin and that precise HbA1c level at insulin initiation was unknown. In addition, they pointed out that neuropathy and retinopathy were determined by self-report, that participants in Look AHEAD were not representative of all patients with type 2 diabetes, and that participants in clinical trials in general may differ from the general population in medical adherence and other factors. However, based on their analysis, the authors noted an independent association between insulin initiation and patient age, race or ethnicity, diabetes complications, and other clinical features in type 2 diabetes. “The predictors of insulin initiation identified in this study should guide future efforts to determine the patient and provider contributions to the insulin transition, and to inform evidence-based strategies for tailoring the use of insulin to a patient's characteristics and needs,” they wrote.