Twenty percent of VA users are estimated to have Type 2 diabetes. In the VA, metformin is commonly used as first line therapy and the usual recommended second-line agent is a member of the sulfonylurea class. Despite the availability and function of these two classes of medication, over half of VA patients with diabetes require further blood sugar lowering medication beyond metformin and sulfonylurea (MET-SU). The two most common drug classes used for patients not achieving adequate glycemic control on MET-SU are thiazolidinediones (TZDs), short- and long-acting insulin, insulin analogues, and human insulin. Unfortunately, there are few data comparing the effectiveness of various medications available for use at this treatment transition.
This project aims to describe the variation in glucose lowering medication prescribing patterns throughout the VA in patients who transition from MET-SU to additional treatments. We will develop a statistical model that predicts variation in glucose lowering medication prescribing patterns. In addition, we will estimate the relationship between anti-diabetic medication prescribing patterns and short and longer-term health outcomes.
This study will examine the causal relationship between prescribing patterns and risk-adjusted health outcomes using a unique national sample of VA patients diagnosed with diabetes (between January 1st, 2000 and December 31st, 2005) and instrumental variables analysis. The criteria for identifying diabetes will be a prescription for anti-diabetes medication in the current year and/or 2+ diabetes codes for inpatient and/or outpatient visits over a two month period. We will require that all patients in the cohort have a medication history that includes both MET-SU and that they add at least one TZD or type of insulin at some point during the study. For risk adjustment and outcomes we will limit the cohort to individuals who are low-income and eligible for Medicare. We will follow all individuals through 2010, but will not add new patients to the cohort after 2005.
Preliminary findings indicated that ongoing use of sulfonylureas after initiation of a 3rd diabetes medication is associated with increased risk of hospitalization for ambulatory care sensitive conditions. Additional analyses demonstrated that initiation of sulfonylureas as a 2nd diabetes medication is also associated with increased risks of hospitalization and mortality. A comparison of outcomes among patients starting NPH or alalogue insulin found no siginificant difference between the two medication classes.
Our findings imply that clinicians should balance the potential benefits of continued use of sulfonylureas against the previously unreported risks of hospitalization for ambulatory care sensitive conditions and mortality. Clinicians and managers should also be aware of the lack of improved outcomes associated with the use of analogue insulin, which is more costly than NPH.
- Prentice JC, Conlin PR, Gellad WF, Edelman D, Lee TA, Pizer SD. Long-term outcomes of analogue insulin compared with NPH for patients with type 2 diabetes mellitus. The American journal of managed care. 2015 Mar 1; 21(3):e235-43.
- Prentice JC, Conlin PR, Gellad WF, Edelman D, Lee TA, Pizer SD. Capitalizing on prescribing pattern variation to compare medications for type 2 diabetes. Value in health : the journal of the International Society for Pharmacoeconomics and Outcomes Research. 2014 Dec 1; 17(8):854-62.
- Prentice JC, Conlin PR, Edelman, D, Gellad W, Lee T, Pizer SD. Comparative Effectiveness of Second Line Agents for Type 2 Diabetes. Poster session presented at: AcademyHealth Annual Research Meeting; 2014 Jun 10; San Diego, CA.
- Prentice JC, Pizer SD. The Power of Observational Data to Compare Treatments for Type 2 Diabetes on Long-Term Outcomes. Presented at: VA Health Economics Resource Center (HERC) Seminar; 2014 Apr 16; Boston, MA.
- Prentice JC, Pizer SD. Are there long-term benefits to prescribing long-acting analogue insulin compared to human insulin? Paper presented at: American Public Health Association Annual Meeting and Exposition; 2013 Nov 6; Boston, MA.
- Prentice J, Conlin P, Edelman D, Gellad WF, Lee T, Pizer S. Are there long-term benefits to prescribing long-acting analogue insulin compared to human insulin? Poster session presented at: AcademyHealth Annual Research Meeting; 2013 Jun 25; Baltimore, MD.
- Pizer S, Prentice J, Gellad WF, Conlin P. Long-term sulfonylurea use increases risks among patients with type 2 diabetes. Paper presented at: AcademyHealth Annual Research Meeting; 2013 Jun 24; Baltimore, MD.
Diabetes and Related Disorders
Treatment - Comparative Effectiveness