Use of a long-term continuous glucose monitor for predicting sulfonylurea dose in patients with neonatal diabetes mellitus: a case series.

Neonatal diabetes mellitus (NDM) is a monogenic form of diabetes that presents with uncontrolled hyperglycemia during the first 6 months of life. NDM is a rare disease in which gene variants mainly cause β-cell loss or dysfunction (6q24 duplication, KCNJ11, and ABCC8). Although NDM is primarily treated through insulin therapy, it is highly challenging to manage blood glucose levels using insulin therapy during infancy. In contrast, KCNJ11 and ABCC8 mutant patients received oral sulfonylureas (SU) instead of insulin injections; however, the dose and frequency differ among individuals. Continuous glucose monitoring (CGM) is useful in patients with type 1 diabetes; but reports on patients with NDM are lacking. Herein, we report two cases of NDM with the KCNJ11 variant. We used CGM not only during insulin injection therapy but also after switching to oral SU therapy. The CGM data can also be used to determine the dose and frequency of SU. Furthermore, long-term CGM may be useful for adjusting SU dose and frequency, and maintaining good glycemic control not only during insulin injection but also during oral SU therapy.