Time to Failure on Oral Glucose-Lowering Agents for Patients with Type 2 Diabetes: A Retrospective Cohort Study

Introduction Research has shown that glycemic control is associated with lower rates of microvascular and long-term cardiovascular complications. In the analyses reported here, we examined treatment failure on oral glucose-lowering agents (GLAs), defined as having sustained hemoglobin A1c (HbA1c) >= 7%. Methods This study utilized the IBM (R) MarketScan (R) Claims and Laboratory Data from 1 January 2012 through 30 June 2018. Adults with type 2 diabetes (T2D) were classified based upon the maximum number of classes of GLAs prescribed per day during the time period from 1 July 2012 through 31 December 2012. Patients were followed for 5.5 years in order to examine time to failure on oral GLAs, defined based upon receipt of >= 2 consecutive HbA1c results >= 7%. Multivariable analyses employing a Cox proportional hazards model were used to examine time to failure overall and based upon the number of index classes of oral GLAs prescribed. For patients who had sustained HbA1c above the threshold, multivariable analyses examined the duration of time that HbA1c remained above the threshold (i.e, glycemic burden) and whether or not an additional oral or injectable class of GLA was added to the patient treatment regimen (i.e., clinical inertia). Results A total of 4156 patients were included in the study, of whom 16% were identified with sustained HbA1c >= 7% after 365 days (1 year) and 36% after 730 days (2 years), with half of all patients having sustained HbA1c above target after 1102 days (3 years). There was a statistically significant difference in time to having sustained HbA1c above target based upon index classes of therapy, with patients treated with more GLAs being quicker to have HbA1c above target (P < 0.0001). Among those patients who were found to have sustained HbA1c >= 7%, the average number of days in the post-period that HbA1c remained above target was 1026 (2.8 years). Only 36% of patients with sustained HbA1c above target added a GLA to their treatment regimen and, for patients who did add such a therapy, the average duration from identification of HbA1c above target until treatment intensification was 401 days (1.1 years). Multivariable analyses revealed that, among those with sustained HbA1c >= 7%, treatment with more classes of oral GLAs was associated with a significantly higher glycemic burden and significantly lower odds of clinical inertia. Conclusion These results indicate that for many patients treated with oral GLAs, glycemic control is not consistently achieved. For patients with above-target HbA1c , the results indicate a relatively large glycemic burden and clinical inertia towards treatment intensification. The findings illustrate some limitations associated with treatment of T2D with oral GLAs.