Risk factors for invasive meningococcal disease: a retrospective analysis of the French national public health insurance database.

Vaccination of at-risk populations against Neisseria meningitidis is an important strategy to prevent invasive meningococcal disease (IMD). The objective of this study was to characterize preexisting risk factors in patients with IMD and to compare their relative importance. This case-control analysis was performed in the French national public health insurance database (SNDS). Cases consisted of all people hospitalized for IMD in France over a six-year period (2012-2017). Controls were matched by age, gender, and district of residence. Medical risk factors were identified from ICD-10 codes in the SNDS. Socioeconomic risk factors studied were low household income and social deprivation of the municipality of residence. Associations of these risk factors with hospitalization for IMD were quantified as odds ratios (ORs) between cases and controls with their 95% confidence intervals (95%CI). The medical risk factors showing the most robust associations were congenital immunodeficiency (OR: 39.1 [95%CI: 5.1-299], acquired immunodeficiency (10.3 [4.5-24.0]) and asplenia/hyposplenia (6.7 [3.7-14.7]). In addition, certain chronic medical conditions, such as autoimmune disorders (5.4 [2.5-11.8]), hemophilia (4.7 [1.8-12.2]) and severe chronic respiratory disorders (4.3 [3.1-6.2]) were also strongly associated, as was low household income (1.68 [1.49-1.80]). In conclusion, this study has documented potential risk factors associated with hospitalization for IMD in a large and comprehensive sample of individuals with IMD in France. Several of the risk factors identified may help identify groups who could benefit from targeted prevention measures (such as vaccination) in order to reduce the burden of IMD.