MedicalResearch.com Interview with:
Christian Hampp PhD
Senior Staff Fellow/Epidemiologist at FDA
Office of Pharmacovigilance and Epidemiology, Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD
MedicalResearch.com: What are the main findings of the study?
Dr. Hampp: Our study described U.S. market trends for antidiabetic drugs, focusing on newly approved drugs, concomitant use of antidiabetic drugs, and effects of safety concerns and restrictions on thiazolidinedione use.
We found that since 2003, the number of adult antidiabetic drug users increased by approximately 43% to 18.8 million in 2012. During 2012, 154.5 million prescriptions for antidiabetic drugs were filled in outpatient retail pharmacies. Since 2003, metformin use increased by 97% to 60.4 million prescriptions dispensed in 2012. Among antidiabetic drugs newly approved for marketing between 2003 and 2012, the dipeptidyl-peptidase-4 (DPP-4) inhibitor sitagliptin had the largest share with 10.5 million prescriptions in 2012.
Possibly triggered by safety concerns, the use of pioglitazone declined in 2012 to approximately 52% of its peak in 2008, when 14.2 million prescriptions were dispensed in outpatient retail pharmacies and the use of rosiglitazone use decreased to fewer than 13,000 prescriptions dispensed in retail or mail-order pharmacies in 2012.
MedicalResearch.com: Were any of the findings unexpected?
Dr. Hampp: Diabetes treatment guidelines recommend that metformin be used as initial therapy and be continued when other antidiabetic drugs are added, unless patients cannot tolerate it or have contraindications to metformin. Yet, our analyses showed that between 33% and 48% of sulfonylurea, DPP-4 inhibitor, thiazolidinedione, and glucagonlike peptide-1 analog use was not accompanied by metformin. It is not clear if intolerance or contraindications to metformin or other reasons can explain this apparent discrepancy between guideline recommendations and actual treatment patterns.
MedicalResearch.com: What recommendations do you have for future research as a result of this study?
Dr. Hampp: Further study is needed to understand why one-third to one-half of other non-insulin antidiabetic drug use was not concomitant with metformin despite guidelines recommending that metformin be continued when other agents are added.