Type 2 diabetes mellitus in people with multiple sclerosis: a systematic review and meta-analysis

Abstract

BACKGROUND: Multiple sclerosis (MS) is an autoimmune disease that causes central nervous system (CNS) inflammation. Investigating comorbidities in people with MS (PwMS) is crucial, as coexisting conditions can negatively impact health outcomes and increase mortality rates. Type 2 diabetes mellitus (T2DM) is one of these comorbidities. Recent literature has not reached a consensus on the effect of MS on the risk of developing T2DM. Moreover, exploring the pooled prevalence of T2DM among PwMS is essential for a comprehensive understanding of this comorbidity burden. Therefore, this review aimed to determine the overall prevalence of T2DM among PwMS and explore any potential association between them. METHODS: PubMed/MEDLINE, Embase, Scopus, and Web of Science were systematically searched up to April 27th, 2024, to identify literature investigating the frequency of T2DM in PwMS and the association between T2DM and MS. The random-effects model was applied to estimate the pooled prevalence, odds ratio (OR), hazard ratio (HR), and their 95 confidence intervals (CIs) for the presentation of outcomes. RESULTS: Forty-five observational studies on 76,189 PwMS and 187,819 healthy controls (HCs) met the inclusion criteria. The analysis revealed the pooled prevalence of T2DM among PwMS was 5 (95 CI: 3.9 to 6.1, I2 = 97, p-heterogeneity < 0.01). Furthermore, there was no significant association between MS and the odds of developing T2DM (OR = 0.92, 95 CI: 0.67 to 1.26, p-value = 0.61, I2 = 92). Additionally, MS did not significantly change the risk of developing T2DM (HR = 1.04, 95 CI: 0.91 to 1.18, p-value = 0.58, I2 = 9). CONCLUSION: The current review indicates a low prevalence of T2DM among PwMS. Additionally, MS does not alter the risk of developing T2DM. The lack of association between MS and T2DM may reduce concerns about the impact of MS treatment on T2DM onset. Furthermore, given the high prevalence of MS, even a low prevalence of T2DM among PwMS could represent a substantial number of affected individuals, highlighting the need for early diagnosis and effective management of T2DM in this population.