The risk of type 2 diabetes mellitus in multiple sclerosis and neuromyelitis optica spectrum disorder: A nationwide cohort study

Background and objectives: An association has been suggested between premorbid type 2 diabetes mellitus (T2DM) and the risk of multiple sclerosis (MS). However, little is known about the risk of developing T2DM in MS and neuromyelitis optica spectrum disorder (NMOSD). This study aimed to determine the T2DM risk in patients with MS and NMSOD. Methods: The Korean National Health Insurance Service database was analyzed, and 1,801 and 1,721 adults with MS and NMOSD, respectively, who were free of T2DM between January 2010 and December 2017, were included. Matched controls were selected based on age, sex, and the presence of hypertension and dyslipidemia. Results: The risk of developing T2DM was 1.54 times higher in NMOSD than in the controls (adjusted hazard ratio [aHR], 95 % confidence interval [CI] = 1.20–1.96). However, increased T2DM risk was not observed in MS (aHR = 1.13, 95 % CI = 0.91–1.42). The T2DM risk in patients with NMOSD was higher in those who received steroid treatment (aHR = 1.77, 95 % CI = 1.36–2.30) but not in those who did not (aHR = 0.59, 95 % CI = 0.24–1.43, p for interaction = 0.02). Discussion: T2DM risk was increased in NMOSD but not in MS. Administering steroid treatment to patients with NMOSD may increase their T2DM risk.