SU-derivaten bij starten insuline: Toch maar stoppen?

Background: Patients with diabetes mellitus type 2 who start insulin therapy are usually also given metformin as oral blood glucose-lowering agent. Some patients are also prescribed a sulphonylurea (SU) derivative, but it is unclear whether this is useful. We investigated whether SU in combination with metformin and insulin has a beneficial efect on beta-cell function and glycaemic control. Method: In this 12-month, multicentre, parallel-group, open-label trial, we followed up 39 patients who were started on insulin glargine because of inadequate glycaemic control. Patients, who were taking metformin and a SU derivative at intake, were randomized to continue or discontinue the SU derivative when they started insulin glargine therapy. The primary outcome was the C-peptide to glucose ratio as estimate of residual beta-cell function. Results: Baseline characteristics were comparable, except for sex, education, and quality-of-life dimensions. After 1 year, the C-peptide to glucose ratio was not significantly different in the two groups (p=0.097); however, the number of hypoglycaemic events was significantly higher (p= 0.043) and the weight gain was also greater, but not significantly so (p=0.054), in the SU group compared with the non-SU group. Conclusion: In this relatively small group, the continuation of SU during treatment with insulin plus metformin did not lead to significant differences in residual beta-cell function; however, there were more hypoglycaemic events in the SU group. These findings suggest that SU derivatives should be discontinued when patients with type 2 diabetes start insulin therapy.