An observational study has shown that patients with type 2 diabetes mellitus treated with a combination of Sitagliptin and Metformin initiated Insulin therapy at a slower rate during the period of observation than patients treated with a combination of sulfonylurea and Metformin.
The retrospective cohort study used a propensity score matched sample from the GE Centricity Electronic Medical Record database, initially including 7,728 patients with type 2 diabetes who used Sitagliptin ( n=3,864 ) or a sulfonylurea ( n=3,864 ) as dual therapy with Metformin for at least 90 days after starting Sitagliptin or the sulfonylurea in 2006 to 2013.
The objectives of the study were to assess the differences in time to initiation of Insulin use and the proportion of the population initiating Insulin among patients taking the combination of Sitagliptin and Metformin, and patients taking the combination of a sulfonylurea and Metformin. Differences in known baseline characteristics, including demographics, clinical and laboratory measures, and comorbidities, were balanced using propensity score matching.
The Kaplan-Meier estimator was utilized to assess the cumulative progression to Insulin use between the groups using Sitagliptin and Metformin, and sulfonylurea and Metformin. The Cox proportional hazards regression model was utilized to assess the progression to Insulin use by year between the two groups.
In the 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 Sitagliptin; 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 ) has shown that patients taking Sitagliptin progressed more slowly to Insulin use than patients taking a sulfonylurea ( p=0.0034 ).
The Cox proportional hazard regression analysis has indicated that by year six, patients in the Sitagliptin group were 24% less likely to initiate Insulin during the period of observation compared to patients taking a sulfonylurea ( hazard ratio, HR = 0.76; p = 0.0011 ).
Similar results were observed in the sub-group of patients with a baseline A1C of less than 9% ( 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% ( HR = 0.75; p = 0.1818 ).
Results of this observational study need to be confirmed through a randomized clinical trial, the gold standard of clinical research. ( Xagena )
Source: American Diabetes Association ( ADA ) 74th Scientific Sessions, 2014