The Expanding Role of New Medications in the Treatment of Type 2 Diabetes Mellitus | Page 2
Published Online: August 21, 2013
Kristen Harrison, MPH; Frederick Brown, PharmD; Brandeis Seymore, RPh; Anthony Palmieri, PharmD, MBA; Olga S. Matlin, PhD; and Steven M. Kymes, PhD
In Table 2, we detailed the observed trends in cost of pharmaceutical treatment for people with diabetes from 2008 to 2012. Between 2008 and 2012, the average annual cost of providing pharmaceutical care for a person with T2DM increased from $667 to $741 (11.1%). During this period, the cost of the those drugs most commonly prescribed for T2DM—biguanides, sulfonylureas, and their combination—declined by over 33%, driven by a generic dispensing rate in excess of 96% for these drug classes. Conversely, the observed increase in cost of care for people with T2DM was driven by the increased annual cost of medication in less commonly prescribed drug classes: the DPP-4 inhibitors, GLP-1 receptor agonists, amylin analogue, and meglitinide agents. Of these, only the DPP-4 inhibitors and GLP-1 receptor agonists had a utilization rate in excess of 2%, and the increase in cost between 2008 and 2012 for DPP-4 inhibitors was 44% and for GLP-1 receptor agonists was 75%.
Between 2008 and 2012, approximately 85% to 90% of people naïve to diabetic medications initiated treatment on monotherapy (Table 3). Most commonly, these people with diabetes were started on biguanide monotherapy(63.8% of utilizers during the study period). For biguanides, the utilization rate as monotherapy increased from 55.5% in 2008 to 67.0% in 2012. During the same period, utilization of sulfonylurea monotherapy decreased from 14.2% to 10.8%. Between 9.9% and 14.7% of people naïve to diabetes therapy were started on more than 1 medication over the study period, most commonly on a combination of sulfonylurea and biguanide, or a combination of sulfonylureas, biguanides, and at least 1 additional drug (Table 3).
In our Uptake Cohort, we examined the addition of DPP-4 inhibitors or GLP-1 receptor agonists in people who were naïve to the use of those medications in 2011. This is illustrated in Figure 2, where, for the sake of clarity, we have scaled our fi gure to represent a hypothetical cohort of 1000 people with T2DM. In 2012, 570 of the 1000 hypothetical cohort members (57%) were on biguanides, 130 (13%) were on sulfonylureas, and 300 (30%) were on both. Less than 1% of those who were naïve to DPP-4 inhibitor or GLP-1 receptor agonist therapy in 2011 were changed to one of these medications as their primary therapy in 2012. Among those on biguanide monotherapy, 5.4% had a DPP-4 inhibitor added to their regimen and 1.6% had a GLP-1receptor agonist added in 2012. For those on sulfonylurea monotherapy, 6.0% had a DPP-4 inhibitor added and 1.2% had a GLP-1 receptor agonist added in 2012. Among the 300 (30%) who were on a combination of biguanide or sulfonylurea in 2012, 28 (9.3% of the subgroup members) had a DPP-4 inhibitor added, 8 (1.9% of the subgroup) had a GLP-1 receptor agonist added, and <1 (0.3% of the subgroup) added both. In this subgroup, there were also 5 members (less than 1.3%) who had their sulfonylurea replaced with DPP-4 inhibitors, GLP-1 receptor agonists, or both. It should be noted that of our 1000 hypothetical cohort members, 914 remained only on biguanides, sulfonylureas, or a combination of those 2 medications—fewer than 95 (or <9.5%) of patients naïve to the use of DPP-4 inhibitors or GLP-1 receptor agonists started therapy on one of those medications during the year.
Impact of New Agents and Pipeline Therapies
In these analyses, we found a prevalence of diabetic medication use of 9.6% among our plan members over the age of 40 years, with an additional 1.2% initiating therapy on diabetic medication each year. At least 70% of these members were on a biguanide, sulfonylurea, or a combination that includes these medications. We estimate that the annual cost of medication for these members was $741 in 2012, a sum that has been increasing at an average rate of 2.7% per year since 2008 despite a reduction in cost of biguanides and sufonylureas.
The new incretin-based therapies—DPP-4 inhibitors and GLP-1 receptor agonists—represent an important option to augment fi rst-line therapies for people with T2DM. Prior to the availability of these medications, first- and second-line treatment options for T2DM were primarily biguanides, sulfonylureas, basal insulin, and thiazolidinediones.5 These new therapies are considered to offer comparable glycemic management with fewer side effects than traditional therapies, including hypoglycemia, weight gain, and edema.6,7 Incretin mimetics have also been reported to improve β-cell function and reduce cardiovascular risk factors.8,9 Recent guidelines from the American Association of Clinical Endocrinologists/ American College of Endocrinology and American Diabetes Association/European Association for the Study of Diabetes support incretin-based therapies as a fundamental treatment option, suggesting that DPP-4 inhibitors and GLP-1 receptor agonists are helpful in treatment of patients with T2DM who are on other glucose-lowering medications and those naïve to therapy. The guidelines also suggest GLP-1 receptor agonists are preferred over the DPP-4 inhibitors because of their superior impact on glycated hemoglobin (A1C) levels.7,10 An additional benefit that has been reported for the GLP-1 receptor agonists is modest weight loss for people with diabetes.7-10
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