Background: Diabetes mellitus is a recognized risk factor for the incidence and severity of several infectious diseases. Invasive Meningococcal Disease, which includes meningitis and sepsis caused by Neisseria meningitidis it’s a high-letality disease. At present, the Italian National Prevention Plan recommends anti-meningoccal vaccination for people with type 1 diabetes. However, it is uncertain whether Diabetes Mellitus is a risk factor for Meningococcal disease and its complications. Aim: This Meta-analysis aims to assess whether Diabetes mellitus is a risk factor for meningococcal invasive disease incidence and case-fatality rate. Material and methods: A meta-analysis was performed (PROSPERO CRD42023483441), including all the observational studies wich reported the invasive meningococcal disease incidence and/or case-fatality rate in people with and without diabetes mellitus. Studies were retrieved through a systematic search of Pubmed and Embase electronic databases. Quality of Studies was assessed through the Newcastle Ottawa Scale (NOS) Results: We included 2 large case-control population-based studies performed in France between 2012 and 2017, and Denmark (1977-2018), both with a high-quality according to NOS; and 2 smaller cohort studies on hospitalized patients performed in New York, USA in 2008-2016 (NOS, high-quality) and in Saudi Arabia in 1993 (NOS moderate-quality). Overall, data on 888 people with diabetes, and 26985 subjects without diabetes were available. The mean age was 45 years Two of those studies reported data on invasive meningococcal disease incidence, whereas 3 studies reported meningococcal disease case fatality-ratio. Diabetes Mellitus was associated with a significant higher incidence of invasive meningococcal disease (MH-OR 1.72 [95%CI 1.15-2.57]. p=0.02, (I 2=74%). Conversely, no significant association could be detected between diabetes and meningococcal disease case-fatality (MH-OR=2.13 [0.58, 7.80], p=0.25, I 2=83%). Only one study reported data on Type 1 DM, showing an OR 2.97 (95%CI 1.60-5.50) for Invasive Meningococcal Disease. Conclusions: Data on the association between diabetes mellitus and meningococcal disease are scarce. Diabetes Mellitus as a whole is associated with a higher risk for invasive meningococcal disease, therefore anti-meningococcal vaccination should be recommended also for people with type 2 diabetes mellitus.
