OBJECTIVE: This study was to determine the prevalence and factors associated with anti-NMDAR encephalitis among affected patients.
MATERIAL AND METHODS: The protocol of this study has been registered (2019: CRD42019142002) with the International Prospective Register of Systematic Reviews (PROSPERO). The primary outcome was the incidence or prevalence of anti-NMDAR encephalitis and secondary outcomes were factors associated with anti-NMDAR encephalitis.
RESULTS: There were 11 studies and a total of 873 million patients taken from high-risk populations across 11 countries that were included in the primary analysis. The overall pooled prevalence of anti-NMDAR encephalitis among patients with medical conditions was 7.0% (95% CI = 4.4, 9.6). Those with first episode of psychosis or schizophrenia were at a higher risk of developing anti-NMDAR encephalitis with an odds ratio of 5.976 (95% CI = 1.122, 31.825).
CONCLUSION: We found that almost one-tenth of patients with medical conditions had anti-NMDAR encephalitis; particularly those with first episode of psychosis or schizophrenia were among the high-risk medical conditions.