Long-acting insulin analogues and the risk of diabetic retinopathy among patients with type 2 diabetes: A population-based cohort study

Aim: To determine whether the use of long-acting insulin analogues is associated with an increased risk of incident diabetic retinopathy (DR) among patients with type 2 diabetes. Methods: Using data from the Clinical Practice Research Datalink Aurum, this retrospective, population-based cohort study included patients with type 2 diabetes who initiated a long-acting insulin analogue (glargine, detemir, degludec) or Neutral Protamine Hagedorn (NPH) insulin. The primary outcome was incident DR. We used Cox proportional hazards models with inverse probability of treatment weighting to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for incident DR with insulin analogues versus NPH insulin. Results: There were 66 280 new users of long-acting insulin analogues and 66 173 new users of NPH insulin. The incidence rate of DR was 101.7 per 1000 person-years (95% CI, 98.7-104.8) for insulin analogues and 93.2 (95% CI, 90.0-96.5) per 1000 person-years for NPH insulin. Compared with the current use of NPH insulin, insulin analogues were not associated with the risk of incident DR (HR 1.04, 95% CI, 0.99-1.09). The adjusted HRs were 0.84 (95% CI, 0.66-1.07) for proliferative DR and 1.02 (95% CI, 0.97-1.08) for non-proliferative DR. Conclusions: Compared with NPH insulin, long-acting insulin analogues were not associated with the risk of incident DR among patients with type 2 diabetes. This finding provides important reassurance regarding the safety of long-acting insulin analogues with respect to incident DR.