Effect of non-persistent use of oral glucose-lowering drugs on HbA_1c goal attainment

ABSTRACT

Objectives: The aim of this study was to quantify the effect of non-persistence with oral glucose-lowering drugs (OGLD) on HbA_1c goal attainment (< 7%) in daily practice.

Methods: From the PHARMO Record Linkage System comprising among others linked drug dispensing and clinical laboratory data from approximately 2.5 million individuals in the Netherlands, new users of OGLD in the period 1999–2004 were identified. Patients with a baseline HbA_1c ≥ 7% and at least one HbA_1c measurement in the period of 6–12 months after treatment onset were included in the study cohort. Persistence with OGLD in the first year of treatment was determined using the method of Catalan. In case the first treatment episode overlapped the first HbA_1c measurement within 6–12 months after treatment onset, a patient was considered persistent at that measurement. Patients with a HbA_1c < 7% were defined as having attained goal.

Results: The study cohort included 2023 patients with a mean baseline HbA_1c of 8.9 ± 1.8%. Three-quarters (1512 patients) were persistent with any OGLD at the first HbA_1c measurement within 6–12 months after treatment onset; of these, 861 (57%) were at goal. Of the 511 non-persistent patients, 239 (47%) were at goal. Non-persistent patients were about 20% less likely to attain goal (RRadj 0.82; 95%CI 0.74–0.91), compared to persistent OGLD users.

Conclusion: Non-persistent use of OGLD leads to a 20% decreased probability of HbA_1c goal attainment in daily practice. This effect of non-persistence seems modest, but represents around 12 000 new and 10 000 prevalent OGLD users a year in the Netherlands in whom OGLD use could be better controlled.

Key Words::

• Daily practice
• HbA_1c goal attainment
• Oral glucose-lowering drugs
• Persistence
• Type 2 diabetes mellitus

Acknowledgements

Declaration of interest: This study was financially supported by an unrestricted grant from Novartis Pharma AG, Basel, Switzerland. No financial limitations were set with regards to the conduct of the study and the writing of the manuscript. S.K. and M.G. are employees of Novartis. F.P., S.B., J.E. and R.H. are employees of the PHARMO Institute. This research institute performs financially supported studies for several pharmaceutical companies, including Novartis.

Notes

* These results have been presented as a podium presentation at the ISPOR 10th Annual European Congress, 20–23 October 2007, Dublin, Ireland