Case fatality rates of invasive meningococcal disease by serogroup and age: A systematic review and meta-analysis.

Introduction: Invasive meningococcal disease (IMD) is uncommon but still causes considerable public health burden due to its high mortality and morbidity. This review aims to quantitatively synthesise all published evidence pertinent to mortality caused by IMD and assess the effect of age and serogroup on case fatality rates (CFRs).

Methods: The PubMed and Embase databases, and the Cochrane Library were searched. Articles reporting national CFRs and published in English between January 2000 and May 2018 were eligible. The studies reporting mortality resulting from a specific symptom of IMD (e.g. meningococcal meningitis) were excluded. Mixed-effects logistic regression with a restricted cubic spline was used to analyse CFRs as a function of age. Random-effects meta-analyses were performed to estimate an overall CFR and CFRs by serogroup.

Results: Among 48 eligible studies reporting national CFRs, 40 studies were included in meta-analyses representing 163,758 IMD patients. CFRs ranged from 4.1% to 20.0% with the pooled overall CFR of 8.3% (95% confidence interval (CI): 7.5-9.1%). Serogroup B was associated with a lower pooled CFR (6.9% (95%CI: 6.0-7.8%)) than other serogroups (W: 12.8% (95%CI: 10.7-15.0%); C: 12.0% (95%CI: 10.5-13.5%); Y: 10.8% (95%CI: 8.2-13.4%)). The meta-analysis was not performed for serogroup A (MenA) cases due to a small number of MenA patients who were enrolled in eligible studies. For laboratory confirmed IMD cases, the predicted CFR was 9.0% in infants, gradually decreased to 7.0% in 7-year olds, subsequently increased to 15.0% in young adults aged 28 years, stabilised between 15 and 20% in mid-aged adults and reached a high in elderly people.

Conclusions: Our findings can provide useful information for better understanding the mortality risks, and quantifying the burden associated with IMD mortality.