Cost effectiveness of insulin glargine plus oral antidiabetes drugs compared with premixed insulin alone in patients with type 2 diabetes mellitus in Canada.
BACKGROUND
Several treatment options are available for patients with type 2 diabetes mellitus who are making the transition from oral antidiabetes drugs (OADs) to insulin. Two options currently recommended by the Canadian Diabetes Association for initiating insulin therapy in patients with type 2 diabetes who are no longer responsive to OADs alone are insulin glargine plus OADs, and premixed insulin therapy only. Because of differences in efficacy, adverse events (such as hypoglycaemia) and acquisition costs, these two treatment options may lead to different long-term clinical and economic outcomes.


OBJECTIVE
To determine the cost effectiveness of insulin glargine plus OADs compared with premixed insulin without OADs in insulin-naive patients with type 2 diabetes in Canada.


METHODS
Using treatment effects taken from a published clinical trial, the validated IMS-CORE Diabetes Model was used to simulate the long-term cost effectiveness of insulin glargine with OADs, versus premixed insulin. Input treatment effects for the two therapeutic approaches were based on changes in glycosylated haemoglobin A(1c) (HbA(1c)) at clinical trial endpoint, and hypoglycaemia rates. The analysis was conducted from the perspective of the Canadian Provincial payer. Direct treatment and complication costs were obtained from published sources (primarily from Ontario) and reported in $Can, year 2008 values. All base-case costs and outcomes were discounted at 5% per year. Sensitivity analyses were conducted around key parameters and assumptions used in the study. Outcomes included direct medical costs associated with both treatment and diabetes-related complications. Cost-effectiveness outcomes included total average lifetime (35 years) costs, life expectancy (LE), QALYs and incremental cost-effectiveness ratios (ICERs).


RESULTS
Base-case analyses showed that, compared with premixed insulin only, insulin glargine in combination with OADs was associated with a 0.051-year increase in LE and a 0.043 increase in QALYs. Insulin glargine plus OADs showed a very slight increase in total direct costs ($Can 343 +/- 2572), resulting in ICERs of $Can 6750 per life-year gained (LYG) and $Can 7923 per QALY gained. However, considerable uncertainty around the ICERs was demonstrated by insulin glargine having a 50% probability of being cost effective at a willingness-to-pay threshold of $Can 10,000 per QALY, and a 54% probability at a $Can 20,000 threshold. Base-case results were most sensitive to assumed disutilities for hypoglycaemic events, to the assumed effect of insulin glargine plus OADs on HbA(1c), and to its assumed acquisition costs.


CONCLUSIONS
These findings should be interpreted within the context of a large degree of uncertainty and of several study limitations that include a single clinical trial as the source for primary treatment assumptions and a single province as the source for most cost inputs. Under current study assumptions and limitations, insulin glargine plus OADs was projected to be a cost-effective option, compared with premixed insulin only, for the treatment of insulin-naive patients with type 2 diabetes unresponsive to OADs. Additional work is needed to examine the generalizability of the findings to individual jurisdictions of the Canadian healthcare system.
Tunis
Sandra L
SL
IMS Health Inc., Falls Church, Virginia, USA.
Sauriol
Luc
L
Minshall
Michael E
ME
D002170:Canada; D003362:Cost-Benefit Analysis; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy* / Q000191:economics*; D004359:Drug Therapy, Combination / Q000191:economics; D005260:Female; D006442:Glycated Hemoglobin / Q000378:metabolism; D006801:Humans; D007004:Hypoglycemic Agents / Q000191:economics* / Q000627:therapeutic use; D007328:Insulin / Q000031:analogs & derivatives* / Q000191:economics / Q000627:therapeutic use; D000069036:Insulin Glargine; D049528:Insulin, Long-Acting; D008297:Male; D008687:Metformin / Q000191:economics* / Q000627:therapeutic use; D008875:Middle Aged; D019057:Quality-Adjusted Life Years; D013453:Sulfonylurea Compounds / Q000191:economics* / Q000627:therapeutic use
D006442:Glycated Hemoglobin; D007004:Hypoglycemic Agents; D007328:Insulin; D000069036:Insulin Glargine; D049528:Insulin, Long-Acting; D008687:Metformin; D013453:Sulfonylurea Compounds; C517652:hemoglobin A1c protein, human; C057619:glimepiride