Using Data From Routine Care to Estimate the Effectiveness and Potential Limitations of Outcomes-Based Contracts for Diabetes Medications.

OBJECTIVES: Outcomes-based contracts tie rebates and discounts for expensive drugs to outcomes. The objective was to estimate the utility of outcomes-based contracts for diabetes medications using real-world data and to identify methodologic limitations of this approach. METHODS: A population-based cohort study of adults newly prescribed a medication for diabetes with a publicly announced outcomes-based contract (ie, exenatide microspheres ["exenatide"], dulaglutide, or sitagliptin) was conducted. The comparison group included patients receiving canagliflozin or glipizide. The primary outcome was announced in the outcomes-based contract: the percentage of adults with a follow-up hemoglobin A1C <8% up to 1 year later. Secondary outcomes included the percentage of patients diagnosed with hypoglycemia and the cost of a 1-month supply. RESULTS: Thousands of adults newly filled prescriptions for exenatide (n = 5079), dulaglutide (n = 6966), sitagliptin (n = 40 752), canagliflozin (n = 16 404), or glipizide (n = 59 985). The percentage of adults subsequently achieving a hemoglobin A1C below 8% ranged from 83% (dulaglutide, sitagliptin) to 71% (canagliflozin). The rate of hypoglycemia was 25 per 1000 person-years for exenatide, 37 per 1000 person-years for dulaglutide, 28 per 1000 person-years for sitagliptin, 18 per 1000 person-years for canagliflozin, and 34 per 1000 person-years for glipizide. The cash price for a 1-month supply was $847 for exenatide, $859 for dulaglutide, $550 for sitagliptin, $608 for canagliflozin, and $14 for glipizide. CONCLUSION: Outcomes-based pricing of diabetes medications has the potential to lower the cost of medications, but using outcomes such as hemoglobin A1C may not be clinically meaningful because similar changes in A1C can be achieved with generic medications at a far lower cost.

Economic model of first-line drug strategies to achieve recommended glycaemic control in newly diagnosed type 2 diabetes mellitus.

OBJECTIVE: To assess the short-term direct medical costs and effectiveness associated with achieving recommended glycaemic goals using commonly prescribed first-line oral antihyperglycaemic medications in type 2 diabetes mellitus. MATERIALS AND METHODS: A literature-based, decision-tree model was developed to project the number of patients achieving glycosylated haemoglobin values of <7% on oral therapies and the associated costs over a 3-year timeframe. For each first-line strategy, patients could progress to combination therapy using two or more agents prior to the introduction of insulin. The overall cost of treatment included costs (2001/2002 values; US dollars) of comprehensive medical care, laboratory tests, patient education, drug therapy, home glucose monitoring and adverse events. RESULTS: At 3 years, the overall cost of treatment for the various first-line strategies was 6,106 US dollars for glipizide gastrointestinal therapeutic system, 6,727 US dollars for metformin immediate release, 6,826 US dollars for metformin extended release, 7,141 US dollars for glibenclamide (glyburide)/metformin, 7,759 US dollars for rosiglitazone and 9,298 US dollars for repaglinide. Costs of comprehensive routine medical care ranged from approximately 1,538-2,128 US dollars in year 1 and from approximately 952-1,543 US dollars in subsequent years, for controlled and uncontrolled patients, respectively. Adverse events represented <1%, and drug therapies represented approximately 50%, of the overall cost, respectively. Substantial cost differences between the strategies were seen within the first year. Regardless of first-line therapy, patients progressed quickly to combination therapies, with effectiveness among the agents being similar. CONCLUSIONS: Short-term costs required to provide comprehensive diabetes care and achieve glycemic goals can be substantial. The model suggests a sulphonylurea strategy may provide similar effectiveness with cost savings over other agents and should be considered when selecting an initial drug therapy in newly diagnosed patients with type 2 diabetes mellitus.

Glipizide. A review of the pharmacoeconomic implications of the extended-release formulation in type 2 diabetes mellitus.

UNLABELLED: Glipizide is a second generation sulphonylurea agent that is available in a Gastrointestinal Therapeutic System (GITS) extended-release formulation. Glipizide GITS provides more stable plasma drug concentrations than the immediate-release formulation and the once-daily regimen may optimise patient compliance. In patients with type 2 diabetes mellitus, glipizide GITS is at least as effective as the immediate-release formulation of glipizide in providing glycaemic control, and may have a greater effect on fasting plasma glucose levels. Any therapeutic advantage over other antidiabetic agents remains to be established, but in a preliminary report (n = 40) glipizide GITS provided better glycaemic control and produced less fasting insulinaemia than glibenclamide (glyburide). The incidence of hypoglycaemic symptoms with glipizide GITS is low (< or = 3%). Quality of life was improved compared with baseline after 12 weeks' treatment with glipizide GITS 5 to 20 mg/day plus diet in a US double-blind, placebo-controlled trial in 569 patients with type 2 diabetes mellitus. Hyperglycaemic symptom-related distress decreased with glipizide GITS treatment, while hypoglycaemic symptom-related distress was not significantly increased compared with placebo plus diet. Quality of life during glipizide GITS treatment has not been compared with that during treatment with other antidiabetic agents. Monthly productivity losses related to absenteeism were $US91 (1995 values) per patient lower in the glipizide GITS group compared with the placebo group in the latter prospective study. Productivity parameters improved slightly or did not change significantly in the glipizide GITS group, but deteriorated in the placebo group. Differences in direct healthcare costs between groups were small and not comprehensively reported. Glipizide GITS was the least costly strategy for first-line therapy in a US cost-of-treatment model of the first 3 years after diagnosis of type 2 diabetes mellitus. The total per-patient cost was $US4867 with glipizide GITS, $US5196 with metformin and $US5249 with acarbose (1996/1997 values). Monthly drug acquisition costs were lower, and glycosylated haemoglobin levels and patient compliance were improved, after formulary conversion from the immediate-release to the GITS formulation of glipizide in a US single-hospital retrospective analysis. CONCLUSIONS: Glipizide GITS produced better cost outcomes than metformin and acarbose in a model of 3 years' treatment of type 2 diabetes mellitus. Glipizide GITS had pharmacoeconomic and quality of life advantages over diet alone in the short term, but more clinically relevant comparisons with other antidiabetic agents are needed. There are limitations to the present data, but the available pharmacoeconomic data have been favourable for glipizide GITS.

A short-term cost-of-treatment model for type 2 diabetes: comparison of glipizide gastrointestinal therapeutic system, metformin, and acarbose.

OBJECTIVE: To compare, from a managed care perspective, the 3-year costs of 3 first-line monotherapy strategies in type 2 diabetes patients: glipizide gastrointestinal therapeutic system (GITS), metformin, and acarbose. STUDY DESIGN: A Markov model, with a Monte Carlo simulation, was developed to compare the costs to achieve full glycemic control (hemoglobin A1c of < or = 7%) with each first-line strategy. PATIENTS AND METHODS: The patient population for the model was assumed to be all newly diagnosed type 2 diabetes patients eligible for monotherapy with an oral agent. Each monotherapy could be succeeded by add-on treatments. The model included the costs of routine medical care and supplies, medication, adverse events, and treatment failures. RESULTS: Using a Monte Carlo simulation, the mean 3-year cumulative costs per patient were $4971, $5273, and $5311 for glipizide GITS, metformin, and acarbose first-line strategies, respectively. The main cost drivers were drug prices. Mean 3-year cost savings for first-line glipizide GITS were $301 over metformin and $340 over acarbose. Between 83% and 85% of all simulations showed cost savings with glipizide GITS compared with the other agents. CONCLUSIONS: The model suggests first-line monotherapy with glipizide GITS should result in desirable short-term economic benefits for managed care. Because the model incorporates recommended glycemic goals and performed well in sensitivity analyses, it should be applicable to a variety of clinical practices and useful for economic assessments of new therapies. Results of this model should be verified prospectively in typical care settings.

Cost-effectiveness analyses of the conversion of patients with non-insulin-dependent diabetes mellitus from glipizide to glyburide and of the accompanying pharmacy follow-up clinic.

At the Department of Veteran's Affairs Outpatient Clinic in Columbus, Ohio, patients with non-insulin-dependent diabetes mellitus who were receiving glipizide therapy were converted to glyburide therapy over a 6-month period starting in mid-1993. A pharmacy follow-up clinic was instituted to help patients with problems associated with the transition. The conversion was intended to reduce costs by converting from a more expensive to a less expensive drug (in terms of acquisition cost) within the same therapeutic class. An initial analysis of the conversion indicated a savings of $65,000.00 to the Department of Veterans' Affairs (VA) based on the drug acquisition cost differential alone. The purpose of our study was to retrospectively evaluate the cost-effectiveness of the conversion and pharmacy follow-up clinic from the perspective of the VA pharmacy department. Relevant costs and effectiveness (percentage of patients who achieved good glycemic control) were examined for three groups: group I--patients who were treated with glipizide, group II--patients who were treated with glipizide; group II--patients who were switched from glipizide to glyburide, accompanied by a pharmacy follow-up clinic; and group III--patients who were switched from glipizide to glyburide, with no follow-up clinic. Overall, group II had the lowest costs, and group II had to be the most effective. Cost-II effectiveness analysis indicated that, in general, the conversion from glipizide to glyburide was cost-effective. Incremental analysis performed for the follow-up group over the no follow-up group showed that for every 1% of patients who achieved good glycemic control, the VA would spend $1.01 more for the follow-up groups. This was considered to be cost-effective for the VA.

Formulary conversion from glipizide to glyburide: a cost-minimization analysis.

Economic pressure prompted us to search for and implement cost-saving strategies at Bronx Municipal Hospital. This paper describes a cost-minimization analysis of the impact of formulary substitution of glyburide for glipizide on glycemic control, safety, and costs. In 76 patients with computerized prescription records, switching from a mean daily glipizide dose of 19 mg to a mean daily glyburide dose of 10.2 mg did not affect glycemic control. A subset of 33 elderly patients experienced only three drug-related adverse events during the 2-year observation period. The conversion program yielded a 51% reduction in overall expenditures for oral hypoglycemic agents between 1991 and 1993. These findings indicate that our conversion program was successful, which has led to its becoming a model for other New York City municipal outpatient pharmacies.

Evaluation of glipizide and glyburide in a health maintenance organization.

OBJECTIVE: To determine if there was a difference in the long-term glycemic control, average daily dose, and cost of therapy in patients with noninsulin-dependent diabetes mellitus (NIDDM) treated with glyburide and glipizide in a health maintenance organization (HMO). DESIGN: Retrospective evaluation of medical and pharmacy records. SETTING: Multispecialty group practice HMO. PATIENTS: 140 NIDDM patients being treated with either glyburide (n = 70) or glipizide (n = 70) were randomly selected from the populations of patients receiving either drug using computerized pharmacy records. MAIN OUTCOME MEASURE: Mean daily doses and blood glucose measurements (fasting blood glucose, random blood glucose, hemoglobin A1C) were stratified in 3-month periods from the time the drug therapy was started or the patient first presented to the clinic for a total of 18 months. Long-term glycemic control was defined as fasting blood glucose less than 8.33 mmol/L (150 mg/dL). RESULTS: The groups were comparable with regard to age (53.4 y glyburide, 56.7 y glipizide), gender (43 M:27 F glyburide, 47 M:23 F glipizide), race (38 W/16 B/16 H glyburide, 45 W/16 B/9 H glipizide), concurrent medical conditions, adverse effects, and compliance. Long-term glycemic control was similar in both groups. Although the number of subjects who were controlled (by definition) tended to be greater in the glyburide group, no clinical or statistical difference was found. There was no statistical difference in mean daily dose between the ethnic groups, but the small numbers preclude further analysis. The glipizide group had a larger percentage increase in dose within the first year than did the glyburide group; however, the percentage increase from the 3-month dose was similar after 18 months (22.7 percent glyburide, 27.5 percent glipizide.) Average daily cost of therapy, based on mean daily dose, was slightly lower for glyburide-treated patients. CONCLUSIONS: If glycemic control is similar with glyburide and glipizide, as seen in this study, economic considerations regarding choice of therapy and formulary inclusion may be appropriate.

Conversion from glipizide to glyburide: a prospective cost-impact survey.

Despite extensive clinical experience with second-generation oral hypoglycemic agents, the relative dosing equivalence of glyburide and glipizide remains controversial. A prospective survey was conducted to determine the feasibility and cost of converting noninsulin-dependent diabetic patients from glipizide to glyburide. A total of 211 patients previously stabilized on glipizide were converted to glyburide and returned to their respective clinics at least once during the following six months. The mean daily dose (+/- SD) of glipizide before conversion was 18.7 +/- 12.32 mg; the mean daily dose of glyburide after seven months was 9.9 +/- 6.52 mg (P less than 0.001, paired t test). Glyburide was well tolerated. The conversion program appeared to be successful and resulted in a 47% reduction in the mean daily dose after conversion from glipizide to glyburide, which, in turn, conferred a 43% savings in the projected yearly expenditures for second-generation oral hypoglycemics.