Predictors of Insulin Initiation in Patients with Type 2 Diabetes: An Analysis of the Look AHEAD Randomized Trial

J Gen Intern Med. 2018 Jun;33(6):839-846. doi: 10.1007/s11606-017-4282-9. Epub 2018 Jan 19.


Background: The decision to initiate insulin in patients with type 2 diabetes is a challenging escalation of care that requires an individualized approach. However, the sociodemographic and clinical factors affecting insulin initiation are not well understood.

Objective: We sought to identify patient factors that were independent predictors of insulin initiation among participants in the Look AHEAD (Action for Health in Diabetes) clinical trial.

Design: Retrospective analysis of a randomized clinical trial.

Participants: Beginning in 2001, Look AHEAD enrolled ambulatory U.S. adults with type 2 diabetes who were overweight or obese and had a primary healthcare provider. Participants were randomized (1:1) to an intensive lifestyle intervention, or diabetes support and education. This study examined 3913 participants across the two trial arms who were not using insulin at baseline.

Main measures: We used Cox proportional hazards models to estimate the association between participant characteristics and time to insulin initiation. We performed time-varying adjustment for HbA1c measured eight times over the 10-year study period, as well as for multiple clinical and socioeconomic factors.

Key results: A total of 1087 participants (27.8%) initiated insulin during a median follow-up of 8.0 years. Age was inversely associated with insulin initiation (adjusted hazard ratio [aHR] 0.88 per 10 years, P = 0.025). The risk of insulin initiation was greater with a higher number of diabetes complications (P < 0.001 for trend); chronic kidney disease and cardiovascular disease were independently associated with insulin initiation. There was a lower risk of insulin initiation in black (aHR 0.77, P = 0.008) and Hispanic participants (aHR 0.66, P < 0.001) relative to white participants. Socioeconomic factors were not associated with insulin initiation.

Conclusions: Patient age, race/ethnicity, and diabetes complications may influence insulin initiation in type 2 diabetes, independent of glycemic control. Future work is needed to understand the drivers of racial differences in antihyperglycemic treatment, and to identify patients who benefit most from insulin.

Trial registration: NCT00017953.

Keywords: diabetes mellitus, type 2; insulin/therapeutic use; pharmacoepidemiology; risk factors.

Publication types

  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, N.I.H., Extramural

MeSH terms

  • Aged
  • Diabetes Mellitus, Type 2 / diagnosis
  • Diabetes Mellitus, Type 2 / drug therapy*
  • Diabetes Mellitus, Type 2 / epidemiology*
  • Female
  • Humans
  • Hypoglycemic Agents / administration & dosage*
  • Insulin / administration & dosage*
  • Longitudinal Studies
  • Male
  • Middle Aged
  • Obesity / diagnosis
  • Obesity / drug therapy
  • Obesity / epidemiology
  • Overweight / diagnosis
  • Overweight / drug therapy
  • Overweight / epidemiology
  • Predictive Value of Tests


  • Hypoglycemic Agents
  • Insulin

Associated data