Comparative cost-effectiveness of metformin-based dual therapies associated with risk of cardiovascular diseases among Chinese patients with type 2 diabetes: Evidence from a population-based national cohort in Taiwan.
OBJECTIVE
To assess the cost-effectiveness of metformin-based dual therapies associated with cardiovascular disease (CVD) risk in a Chinese population with type 2 diabetes.


METHODS
We utilized Taiwan's National Health Insurance Research Database (NHIRD) 1997-2011, which is derived from the claims of National Health Insurance, a mandatory-enrollment single-payer system that covers over 99% of Taiwan's population. Four metformin-based dual therapy cohorts were used, namely a reference group of metformin plus sulfonylureas (Metformin-SU) and metformin plus acarbose, metformin plus thiazolidinediones (Metformin-TZD), and metformin plus glinides (Metformin-glinides). Using propensity scores, each subject in a comparison cohort was 1:1 matched to a referent. The effectiveness outcome was CVD risk. Only direct medical costs were included. The Markov chain model was applied to project lifetime outcomes, discounted at 3% per annum. The bootstrapping technique was performed to assess uncertainty in analysis.


RESULTS
Metformin-glinides was most cost-effective in the base-case analysis; Metformin-glinides saved $194 USD for one percentage point of reduction in CVD risk, as compared to Metformin-SU. However, for the elderly or those with severe diabetic complications, Metformin-TZD, especially pioglitazone, was more suitable; as compared to Metformin-SU, Metformin-TZD saved $840.1 USD per percentage point of reduction in CVD risk. Among TZDs, Metformin-pioglitazone saved $1831.5 USD per percentage point of associated CVD risk reduction, as compared to Metformin-rosiglitazone.


CONCLUSIONS
When CVD is considered an important clinical outcome, Metformin-pioglitazone is cost-effective, in particular for the elderly and those with severe diabetic complications.
Institute of Clinical Pharmacy and Pharmaceutical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan. Electronic address: huangtz@mail.ncku.edu.tw.
Huang-Tz
HT
Ou
Institute of Clinical Pharmacy and Pharmaceutical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
Yen-Ting
YT
Chen
Department of Economics, National Cheng Kung University, Tainan, Taiwan.
Ya-Ming
YM
Liu
Department of Family Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Department of Family Medicine, National Cheng Kung University Hospital, Tainan, Taiwan.
Jin-Shang
JS
Wu
D020909:Acarbose / Q000191:economics / Q000627:therapeutic use; D000368:Aged; D002318:Cardiovascular Diseases / Q000191:economics / Q000453:epidemiology*; D003362:Cost-Benefit Analysis; D048909:Diabetes Complications / Q000191:economics / Q000453:epidemiology*; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy* / Q000191:economics; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D007004:Hypoglycemic Agents / Q000191:economics / Q000627:therapeutic use*; D008297:Male; D008390:Markov Chains; D008687:Metformin / Q000191:economics / Q000627:therapeutic use*; D008875:Middle Aged; D000077205:Pioglitazone; D012306:Risk; D000077154:Rosiglitazone; D013453:Sulfonylurea Compounds / Q000191:economics / Q000627:therapeutic use*; D013624:Taiwan / Q000453:epidemiology; D045162:Thiazolidinediones / Q000191:economics / Q000627:therapeutic use*
D007004:Hypoglycemic Agents; D013453:Sulfonylurea Compounds; D045162:Thiazolidinediones; D000077154:Rosiglitazone; D008687:Metformin; D020909:Acarbose; D000077205:Pioglitazone
Cardiovascular diseases; Cost effectiveness analysis; Metformin-based dual therapy, Chinese; Type 2 diabetes mellitus