Effects of obesity on metabolic and cardiovascular outcomes following insulin initiation in patients with type 2 diabetes

Abstract

Objectives: Insulin therapy induces weight gain but whether it causes long term adverse metabolic and CV outcomes in obese patients remains unclear.

Methods: A retrospective cohort study of 12,725 insulin initiators with T2D derived from UK General Practices. Multivariate linear, logistic regression analyses and Cox proportional hazard models were used to estimate HbA1c, BMI, risk of composite CV events between baseline BMI categories at 5 years.

Results: Mean age was 58.6±13.8years. The proportion of patients achieving HbA1c targets decreased across increasing BMI categories at 6 and at 12 months; p=0.0001, but not significant beyond 24 months. 1095 composite events of all-cause mortality, non-fatal stroke and MI occurred with an adjusted hazard risk (aHR) relative to normal of: (1.10; 95%CI: 0.90-1.35) in the overweight, (1.05; 95%CI: 0.86-1.29) in the obese class I, (1.03; 95%CI: 0.83-1.29) in the obese class II and (1.30; 95%CI: 1.02-1.66) in the obese class III BMI categories.

Conclusion: Among patients with T2D insulin initiators, obesity adversely influences HbA1c up to 12 months, but not beyond 24 months and is associated with a decrease in BMI compared to non-obese groups. Morbidly obese patients initiating insulin have 30% increased risk of composite CV events after 5 years.

Keywords: Cardiovascular; Insulin; Mortality; Obesity; Type 2 diabetes.