Assessment of the TECOS study
Sitagliptin (trade names: Januvia, Xelevia) has been approved in Germany since March 2007 for the treatment of type 2 diabetes in adults who can't lower their blood sugar levels enough through exercise and diet alone and if certain other treatments aren't an option or aren't effective enough.
In 2015, a major study on sitagliptin involving more than 14,000 men and women with diabetes was published. This study is called the TECOS study. It looked into whether sitagliptin, when given in addition to standard diabetes treatment, influences the risk of cardiovascular disease such as heart attacks or strokes in adults who have diabetes and existing cardiovascular disease.
But according to the Institute for Quality and Efficiency in Health Care (IQWiG, Germany), the data from this study can't be used to draw any conclusions relevant to standard clinical practice in Germany. Analysis of the data showed that the study participants weren't given the standard diabetes treatment used in Germany.
Who participated in the TECOS study?
This study involved people with diabetes who had been treated with metformin, glitazones or sulfonylureas (either alone as monotherapy or in combination) in the three months before the study started. People who had been treated with insulin or the combination insulin/metformin in the three months before the study started could also participate. The dose of medication had to remain constant over those three months. As well as having diabetes, all participants had existing cardiovascular disease, such as a past heart attack or stroke.
The average age of the participants at the beginning of the study was between 65 and 66. This was also an international study, with 38 countries participating.
Which treatments were compared?
The participants were randomly assigned to one of two groups:
- 7,332 men and women were given 50 or 100 mg of sitagliptin per day in addition to their previous diabetes treatment.
- 7,339 men and women were given a placebo (dummy drug) in addition to their usual diabetes treatment.
If the treatment affected kidney function, the dose of sitagliptin could be reduced during the study.
What did they find?
The results of the study showed that people who had additional treatment with sitagliptin experienced damage to the retina (retinopathy) more often than people who had additional "treatment" with a placebo. Severe hyperglycemia (high blood sugar) requiring a hospital stay was less common in people who had additional treatment with sitagliptin, though.
There were no differences between the groups in terms of the following:
- Life expectancy
- The number of cardiovascular events such as strokes or heart attacks
- Hospital admissions due to heart failure
- Side effects
The study didn't look into health-related quality of life. No usable data was available regarding symptoms due to hypoglycemia (low blood sugar).
Institute for Quality and Efficiency in Health Care (IQWiG, Germany). Sitagliptin (Diabetes mellitus Typ 2 - Benefit assessment according to §35a Social Code Book V; Dossier assessment; Commission A16-44. September 30, 2016. (IQWiG reports; Volume 444).
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