gms | German Medical Science

Background: Dipeptidyl peptidase-4 (DPP-4) inhibitors are a newer class of oral anti-hyperglycemic agents for the treatment of type 2 diabetes. They have shown reduction of blood glucose, but potential impact on cardiovascular outcomes and long-term safety remain inconclusive. For that reasons DPP-4 inhibitors should only be used, if blood glucose is inadequately controlled by metformin or if metformin is not tolerated. Furthermore the authorization requests, that before use of DPP-4 inhibitors patients should have tried diet and movement and metformin. DPP-4 inhibitors can be added if metformin is not sufficiently effective or can be used as monotherapy if metformin is contraindicated. Though an increase in DPP-4 inhibitor prescribing can be noticed. Therefore we tried to examine in which constellation DPP-4 inhibitors are mainly used.

Materials and Methods: The Techniker Krankenkasse (TK) is a large German health insurance company with more than 8.2 million insured. We used medication prescription data of TK from January 2013 to September 2013. We identified type 2 diabetes patients with first DPP-4 inhibitor (or GLP-1 analog) prescription by using ATC/DDD classification according to WIdO. DPP-4 inhibitor prescriptions were detected by 7-digit ATC-Codes A10BH01, A10BH02 and A10BH03 for monotherapy and 7-digit ATC-Codes A10BD07, A10BD08 and A10BD010 for fixed combination with metformin. GLP-1 analog prescriptions were obtained from 7-digit ATC-Codes A10BX04, A10BX07 and A10BX10. Prescription was considered to be first one if prescription of at least one of the mentioned 7-digit ATC-Codes occurred between January and September 2013 but none in 2012 (based on recipe issue date). We analyzed, if patients had prescription of other antidiabetic agents, except insulin, within one year prior first prescription. We searched for metformin (A10BA), sulfonylurea (A10BB) or combination of both by using 5-digit ATC-Code. Other antidiabetic drugs (A10BF, A10BG, and A10BD) were also identified, but not considered in detail.

Results: We identified 15.259 insured with first DPP-4 inhibitor/GLP-1 analog prescription between January and September 2013. 27.0% of the patients had no upfront antidiabetic drug therapy. 49.9% had metformin to reduce blood glucose, 4.3% had sulfonylurea and 13.8% combination of both. Interestingly also fixed combination of DPP-4 inhibitor and metformin was used for first prescription of DPP-4 inhibitors for 6.775 patients. 26.3% of these patients had no other antidiabetics before. 2.1% were treated with sulfonylurea, 14.5% with combination of sulfonylurea and metformin and 52.9% with metformin. This means that at least 26.3% had inappropriate prescription of metformin, because no metformin was used before starting DPP-4 inhibitor therapy and contraindications must be negated, because fixed combination with metformin was used.

Conclusion: Routine data of a sickness fund can be used for Health Services Research. Our results suggest that DPP-4 inhibitors are used inappropriately in every fourth patient. The early use of DPP-4 inhibitors might be associated with potential harm for each patient as well as financial burden for the community. But secondary data of course have limitations. However our findings encourage to pay more attention on prescribing of DPP-4 inhibitors.