Type 2 Diabetes: Combination JANUVIA and Metformin May Delay Need for Insulin

MedicalResearch.com Interview with:
Peter Stein, M.D.
Vice president, Clinical Research for Diabetes and Dndocrinology
Merck Research Laboratories.

MedicalResearch: What are the main findings of the study?

Dr. Stein: This late-breaking observational study assessed the differences in time to initiation of insulin use and the proportion of the population initiating insulin among patients with type 2 diabetes taking the combination of JANUVIA® (sitagliptin) and metformin, and patients taking the combination of a sulfonylurea and metformin.  In this study, patients treated with a combination of JANUVIA and metformin initiated insulin therapy at a slower rate during the period of observation than patients treated with a combination of sulfonylurea and metformin.

In this study, the percentages of patients initiating insulin by years one through six were 3.6, 8.4, 12.9, 17.7, 22.4, 26.6 for patients taking JANUVIA; and 4.1, 9.4, 14.6, 21.0, 27.1, 34.1 for patients taking a sulfonylurea. An analysis of the data overall (Kaplan-Meier method) showed that patients taking JANUVIA progressed more slowly to insulin use than patients taking a sulfonylurea (p=0.0034). The Cox proportional hazard regression analysis indicated that by year six, patients in the JANUVIA group were 24 percent less likely to initiate insulin during the period of observation compared to patients taking a sulfonylurea (HR = 0.76; p = 0.0011).

Similar results were observed in the sub-group of patients with a baseline A1C of less than 9 percent (HR = 0.77; p = 0.0128]; however there was no statistically significant difference in time to insulin initiation in the sub-group with a baseline A1C of greater than or equal to 9 percent (HR = 0.75; p = 0.1818).

MedicalResearch: What should clinicians and patients take away from your report?

Dr. Stein: Type 2 diabetes is a progressive disease, so that over time many patients need to add insulin to their treatment regimens to maintain blood sugar control. This study provides insight about different oral treatment regimens and their possible effect on initiation of insulin under real-world conditions. Real-world research is an important complement to clinical trials as we seek to improve patient health outcomes.

MedicalResearch: What recommendations do you have for future research as a result of this study?

Dr. Stein: These findings provide meaningful insights for physicians in the practice setting.

Results of this observational study need to be confirmed through a randomized clinical trial, the gold standard of clinical research.

There were a number of limitations for this study:

  • Day-of-supply for prescription and stopping dates of medications were unavailable for a considerable number of patients.
  • Treatment sequences were primarily estimated based on the prescription dates.
  • While the database captured prescription and medication information, it could not be ascertained that patients adequately followed the prescribing physicians’ instructions in filling their prescriptions or taking the medications. It is possible that patients never or only partially filled the prescription.
  • Due to the absence of prescription refill data, the prescription data alone could not fully account for treatment adherence and therapy type (i.e., dual therapy versus triple therapy).
  • The Cox proportional hazard regression analysis does not account for changes in concomitant therapies and/or comorbidities that may have occurred after initiation of sitagliptin or sulfonylurea.
  • Although propensity score matching creates balanced treatment groups based on observed baseline characteristics, the possibility of potential imbalances between matched groups with regard to unobserved characteristics cannot be excluded.
  • Due to the methods employed in this analysis, the time period in which an outcome can be observed must be pre-specified and patients without complete data needed to be excluded.

Citation:

Data presented at the 74th Scientific Sessions of the American Diabetes Association

Assessing time to insulin use among type 2 diabetes patients treated with sitagliptin or sulfonylurea plus metformin dual therapy

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