COMMENTARY

Are Patients With Newly Diagnosed Diabetes Mellitus Being Prescribed Metformin?

Gregory A. Nichols, PhD

May 11, 2012

Patterns of Medication Initiation in Newly Diagnosed Diabetes Mellitus: Quality and Cost Implications

Desai NR, Shrank WH, Fischer MA, et al
Am J Med. 2012;125:302.e1-302.e7

Study Summary

This retrospective analysis of prescription claims data covered 254,973 diabetes patients who were newly initiated on oral hypoglycemic monotherapy between January 2006 and December 2008. The researchers then analyzed the monthly frequency of prescriptions for each class of antidiabetic medications along with the associated costs.

The proportion of patients initially treated with metformin increased from 51% to 65% over the 3-year period. Prescriptions for sulfonylureas decreased from 26% to 18% over the same period. Thiazolidinedione (TZD) use also declined significantly from 20.1% to 8.3%, while the use of dipeptidyl peptidase-4 (DPP-4) inhibitors grew from 0.4% to 7.3%.

Over a 6-month period, the cost for patients who were initiated on agents other than metformin or sulfonylureas was $677 per patient. The cost for those initiated on metformin or a sulfonylurea, by contrast, was $116 and $118, respectively.

Viewpoint

The American Diabetes Association and the European Association for the Study of Diabetes currently recommend initiating metformin when diabetes is first diagnosed,[1] a recommendation that was already in place over the course of this study.[2] It is rather disturbing, then, that about 35% of newly initiated therapy in this study was for something other than metformin, especially considering the substantial cost differences between metformin and other agents (except sulfonylureas).

The latest clinical guideline from the American College of Physicians does not call for metformin initiation at diagnosis, but it does recommend metformin as the initial therapy after lifestyle modifications have failed.[3] However, observational studies have suggested that patients are more likely to attain glycemic goals with metformin, and to maintain them for longer periods, when initiated at diagnosis and before glycemic levels have been allowed to rise.[4,5] In any case, whether initiated immediately or after attempting lifestyle changes, metformin should be the first medication attempted.

Another disturbing finding was that patients receiving pharmacy coverage from Medicare or sources other than employer or carve-out plans were less likely to receive metformin. This suggests that patients with coverage sources that do not include cost containment-based formularies were more likely to start newer and more expensive medications. Whether there was clinical justification for this could not be determined from the data, but the implications demand further investigation.

Abstract

References

  1. Nathan DM, Buse JB, Davidson MB, et al. Medical management of hyperglycemia in type 2 diabetes: a consensus algorithm for the initiation and adjustment of therapy: a consensus statement of the American Diabetes Association and the European Association for the Study of Diabetes. Diabetes Care. 2009;32:193-203. Abstract

  2. Nathan DM, Buse JB, Davidson MB, et al. Management of hyperglycaemia in type 2 diabetes: a consensus algorithm for the initiation and adjustment of therapy. A consensus statement from the American Diabetes Association and the European Association for the Study of Diabetes. Diabetologia. 2006;49:1711-1721. Abstract

  3. Qaseem A, Humphrey LL, Sweet DE, Starkey M, Shekelle P, for the Clinical Guidelines Committee of the American College of Physicians. Oral Pharmacologic Treatment of Type 2 Diabetes Mellitus: A Clinical Practice Guideline From the American College of Physicians. Ann Intern Med. 2012;156:218-231. Abstract

  4. Nichols GA, Conner C, Brown JB. Initial nonadherence, primary failure and therapeutic success of metformin monotherapy in clinical practice. Curr Med Res Opin. 2010;26:2127-2135. Abstract

  5. Brown JB, Conner C, Nichols GA. Secondary failure of metformin monotherapy in clinical practice. Diabetes Care. 2010;33:501-506. Abstract