Costs and Consequences Associated With Newer Medications for Glycemic Control in Type 2 Diabetes
Article Figures & Tables
Figures
- Figure 1
Daily treatment costs. Over 15 years, the average daily treatment costs for the glyburide, sitagliptin, and exenatide strategies were $2.98, $6.51, and $7.26, respectively.
Tables
- Table 1
Assumptions regarding model parameters
Value Reference Diabetes-related parameters Interval between onset of diabetes and diagnosis (years) 10 15 Average hemoglobin A1C at time of diagnosis (%) 6.80 15 Treatment impact on A1C (%) −2.90 15 Rate of change in A1C, on treatment (%) 0.20 15 Hazard rates Normal to microalbuminuria 0.02371 Microalbuminuria to nephropathy 0.06561 Normal to peripheral neuropathy 0.0294 Normal to photocoagulation 0.0079 Side effect–related parameters Probability of weight gain while on glyburide (first 2 years) (%) 100 33 Probability of weight loss while on exenatide (first 2 years) (%) 100 33 Probability of hypoglycemia (%) Glyburide 36.10 12 Sitagliptin 6.20 12 Exenatide 16.00 34 Probability of nausea/other gastrointestinal side effects while taking glyburide (%) 4.20 19 Probability of nausea/other gastrointestinal side effects while taking exenatide (%) 57.00 13 Probability of upper respiratory infection while on sitagliptin (%) 3.50 19 Costs per day ($) Metformin, 2,000 mg 1.42 WSP, 35 Glyburide, 7.5 mg 0.42 WSP, 35 Sitagliptin, 100 mg 6.06 WSP, 35 Exenatide, 20 μg 8.37 WSP, 35 Rosiglitazone, 8 mg 5.59 WSP, 35 NPH insulin, 10 units 0.90 WSP, 35 Injection-related supplies 0.52 WSP, 35 Annual utilities following Blindness 0.69 15 Stroke 0.5 15 End-stage renal disease 0.61 15 Lower extremity amputation 0.8 15 WSP, wholesale price.
- Table 2
Side effect–related quality-of-life assumptions
Side effect Glyburide Exenatide Sitagliptin Reference Weight gain/loss −0.0031 0.0013 0 33 Hypoglycemia −0.0064 −0.0005 −0.0002 12,34,36 Nausea/gastrointestinal side effects 0 −0.0005 0 Authors' assumption; 13,33 Upper respiratory infections 0 0 −0.0001 13 Injectable 0 −0.0032 0 Authors' assumption Overall disutility associated with side effects, after weighting* −0.0095 −0.0029 −0.0003 A positive number (utility) indicates a gain in quality of life, and a negative number (disutility) indicates a loss in quality of life.
↵*The overall disutility was calculated as the weighted sum of the side effect utilities/disutilities, where the weights were 1) the probability a patient was on a given medication at a point in time and 2) the probability the side effect occurred.
- Table 3
Results of cost-effectiveness analysis
Intensive control treatment strategies Cost of medications Total costs Incremental costs QALYs Incremental QALYs Incremental cost-effectiveness ratio* Cost-effectiveness ratio, relative to glyburide strategy Glyburide as second-line therapy $65,205 $146,950 — 15.2143 — — — Sitagliptin as second-line therapy $85,418 $4,167,163 $20,213 15.3335 0.1192 $169,572 $169,572 Exenatide as second-line therapy $89,054 $170,799 $3,636 15.2998 −0.0337 Dominated $278,935 ↵*Changes in costs in $ and QALYs were calculated relative to the next most expensive treatment strategy.
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