PURLs

Need an Add-on to Metformin? Consider This

Clinician Reviews. 2017 February;27(2):20-22

References

1. Ou SM, Shih CJ, Chao PW, et al. Effects of clinical outcomes of adding dipeptidyl peptidase-4 inhibitors versus sulfonylureas to metformin therapy in patients with type 2 diabetes mellitus. Ann Intern Med. 2015;163:663-672.
2. Hayward RA, Reaven PD, Wiitala WL, et al. Follow-up of glycemic control and cardiovascular outcomes in type 2 diabetes. N Engl J Med. 2015;372:2197-2206.
3. American Diabetes Association. Standards of Medical Care in Diabetes—2016. Diabetes Care. 2016;39(suppl 1).
4. Garber AJ, Abrahamson MJ, Barzilay JI, et al. Consensus Statement by the American Association of Clinical Endocrinologists and American College of Endocrinology on the Comprehensive Type 2 Diabetes Management Algorithm—2016 Executive Summary. Endocr Pract. 2016;22: 84-113.
5. Phung OJ, Scholle JM, Talwar M, et al. Effect of noninsulin antidiabetic drugs added to metformin therapy on glycemic control, weight gain, and hypoglycemia in type 2 diabetes. JAMA. 2010;303:1410-1418.
6. Gallwitz B, Rosenstock J, Rauch T, et al. 2-year efficacy and safety of linagliptin compared with glimepiride in patients with type 2 diabetes inadequately controlled on metformin: a randomised, double-blind, non-inferiority trial. Lancet. 2012;380:475-483.
7. Scirica BM, Bhatt DL, Braunwald E, et al. Saxagliptin and cardiovascular outcomes in patients with type 2 diabetes mellitus. N Engl J Med. 2013;369:1317-1326.
8. Filion KB, Azoulay L, Platt RW, et al. A multicenter observational study of incretin-based drugs and heart failure. N Engl J Med. 2016;374:1145-1154.
9. Chan JC, Malik V, Jia W, et al. Diabetes in Asia: epidemiology, risk factors, pathophysiology. JAMA. 2009;301:2129-2140.
10. Gangji AS, Cukierman T, Gerstein HC, et al. A systematic review and meta-analysis of hypoglycemia and cardiovascular events: a comparison of glyburide with other secretagogues and with insulin. Diabetes Care. 2007;30:389-394.
11. Nathan DM, Buse JB, Kahn SE, et al. Rationale and design of the glycemia reduction approaches in diabetes: a comparative effectiveness study (GRADE). Diabetes Care. 2013;36:2254-2261.
12. GoodRx. Gliptins. www.goodrx.com/gliptins. Accessed January 4, 2017.

CAVEATS

Did unmeasured confounders play a role?

Unmeasured confounders potentially bias all observational population cohort results. In this particular study, there may have been unmeasured but significant patient factors that providers used to choose diabetes medications. Also, the study did not evaluate diabetes control, although previous studies have shown similar glucose control between sulfonylureas and DPP-4 inhibitors when added to metformin.⁶

Another caveat is that the results from this study group may not be generalizable to other populations due to physiologic differences. People of Asian ancestry are at risk for T2DM at a lower BMI than people of European ancestry, which could affect the outcomes of interest.⁹

Furthermore, the study did not evaluate outcomes based on whether patients were taking first-, second-, or third-generation sulfonylureas. Some sulfonylureas (eg, glyburide) carry a higher risk for hypoglycemia, which could bias the results.¹⁰

Lastly, the study only provides guidance when choosing between a sulfonylurea and a DPP-4 inhibitor for secondline pharmacotherapy. The GRADE trial, due to be completed in 2023, is comparing sulfonylureas, DPP-4 inhibitors, GLP-1 agonists, and insulin as add-on medications to metformin; it may provide more data on which to base treatment decisions.¹¹

CHALLENGES TO IMPLEMENTATION

DPP-4s are more expensive

Sulfonylureas and DPP-4 inhibitors are both available as generic medications, but the cost of DPP-4 inhibitors remains significantly higher.¹² Higher copays and deductibles could affect patient preference. For patients without health insurance, sulfonylureas are available on the discounted drug lists of many major retailers, while DPP-4 inhibitors are not.

ACKNOWLEDGEMENT

The PURLs Surveillance System was supported in part by Grant Number UL1RR024999 from the National Center For Research Resources, a Clinical Translational Science Award to the University of Chicago. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Center For Research Resources or the National Institutes of Health.

Reprinted with permission from the Family Physicians Inquiries Network and The Journal of Family Practice. 2017;66(1):42-44.

Need an Add-on to Metformin? Consider This

References

CAVEATS

Did unmeasured confounders play a role?

CHALLENGES TO IMPLEMENTATION

DPP-4s are more expensive

ACKNOWLEDGEMENT

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