Trends in the use of oral antidiabetic drugs by outpatients in Taiwan: 1997-2003

To define the prescribing patterns of oral antidiabetic drugs (OADs) in Taiwan over a 7-year period (1997-2003) and to critically comment on changes observed. A cross-sectional study design was implemented using data from Taiwan's National Health Insurance Research Database between January 1997 and December 2003. Outpatients who were 18 years or older and had at least an OAD claim during the study period were identified. The unit of analysis was each OAD prescription for diabetic outpatient visits. The prescribing trends were described in terms of annual changes in prescribing rates and patterns. The numbers of OAD prescriptions rose 1.23-fold. The sulfonylurea (SU) class was the most commonly used OAD, but the prescribing rates for this class declined over time. The biguanide (BG) class was the second most frequently prescribed OAD class and its prescribing rate initially increased, peaked in 2000, and then substantially decreased. The largest increase in prescribing was for acarbose use. The prescribing rates of two new classes of OAD, meglitinide (MG) and thiazolidinedione (TZD), also significantly increased within a short period of time. A trend towards combination therapy was observed away from monotherapy. The SU class was the most commonly prescribed as monotherapy. SU plus BG was the most commonly prescribed dual therapy. Triple oral therapy showed a significant ninefold increase. The prescribing rates of OADs are shifting from the older OADs (i.e. SUs) to newer OADs [i.e. alpha-glucosidase inhibitor (AGI), MGs, and TZDs]. The prescribing patterns of OADs are moving toward combination therapy, especially triple oral therapy.