U.S. insulin pricing began increasing dramatically in 2010, possibly caused by rising artificial insulin production and market domination by several pharmaceutical companies. Studies over the last 20 years have shown that such high prices are associated with patient rationing of insulin. The commercially-insured population includes patients with both type 1 and 2 diabetes who have experienced increasing cost sharing over the last decade, often in the form of high deductible health plans. This rise in insulin pricing combined with higher cost sharing might increase life-threatening diabetes-related complications. We hypothesized that diabetic ketoacidosis (DKA) and hyperosmolar coma (HOC) would increase after the sharp rise in insulin prices that began in 2010. We applied an interrupted times series design, with 2010 used as the change point given previous research showing that insulin prices began rising sharply in this year. We studied a large commercially insured population with an average annual number of diabetes patients of 507,578 during 2005-2014. Patients with diabetes were identified using a standard algorithm based on ICD9 codes and oral antidiabetes medicines. We calculated annual emergency department visit rates for combined DKA and HOC in this population. We use a first-order autoregressive segmented regression model to determine if there was a change in the complication trend from before to after 2010. The estimated 2005 rate of DKA and HOC emergency department visits was 50.9 per 10,000 diabetes patients (p<0.001), which decreased to 36.2 per 10,000 by 2009 (trend: -3.7 per 10,000 per year; p<0.001). However, from 2010-2014 the complication rate rose by 5.2 per 10,000 per year (p=0.002) relative to the 2005-2009 trend.
In conclusion, life-threatening hyperglycemia-related complications among commercially-insured diabetes patients increased after the 2010 insulin price increase.
A. Meiri: None. K. Callaway: None. J. Wharam: None.
National Institutes of Health; Centers for Disease Control and Prevention