title: Increased rates of sequelae post-encephalitis in individuals attending primary care practices in the United Kingdom: a population-based retrospective cohort study.
abstract: The true extent of sequelae in encephalitis survivors relative to rates within the general population is not known. This study aimed to quantify increased risks of epilepsy, depressive disorders, anxiety disorders, psychotic disorders, bipolar disorder, cognitive problems, dementia, headache, and alcohol abuse among encephalitis cases. 2460 exposed individuals diagnosed with incident encephalitis in the Clinical Practice Research Datalink and 47,914 unexposed individuals without a history of encephalitis were included. Multivariable Poisson regression was used to estimate adjusted rate ratios in individuals with encephalitis compared to the general population and to estimate whether the effect of these outcomes varied over time. Individuals with encephalitis had an increased risk of all investigated outcomes. The highest RR was seen for epilepsy (adjusted RR 31.9; 95 % confidence interval 25.38-40.08), whereas the lowest was seen for anxiety disorders (1.46, 1.27-1.68). The second highest RRs were for particular psychiatric illnesses, including bipolar disorder (6.34, 3.34-12.04) and psychotic disorders (3.48, 2.18-5.57). The RR was highest in the first year of follow-up for all outcomes except headache; this was particularly true for epilepsy (adjusted RR in first year of follow-up 139.6, 90.62-215.03). This study shows that sequelae are common in survivors of encephalitis. We confirm the presence of outcomes more commonly linked to encephalitis and describe those less commonly identified as being associated with encephalitis. The results of this study have important implications for the management of encephalitis patients and for the design of tertiary prevention strategies, as many of these sequelae are treatable.
authors.affiliation: Virus Reference Department, Public Health England, National Infection Service, 61 Colindale Avenue, London, NW9 5EQ, UK. juliagranerod@hotmail.com.
authors.forename: Julia
authors.initials: J
authors.lastname: Granerod
authors.affiliation: Department of Neurology, Chelsea and Westminster Hospital, London, SW10 9NH, UK.
authors.forename: Nicholas W S
authors.initials: NW
authors.lastname: Davies
authors.affiliation: New York State Psychiatric Institute, New York, NY, 10032, USA.
authors.forename: Parashar P
authors.initials: PP
authors.lastname: Ramanuj
authors.affiliation: Encephalitis Society, Malton, YO17 7DT, UK.
authors.forename: Ava
authors.initials: A
authors.lastname: Easton
authors.affiliation: Virus Reference Department, Public Health England, National Infection Service, 61 Colindale Avenue, London, NW9 5EQ, UK.|Influenza Laboratory, Oswaldo Cruz Institute/Fiocruz, Rio de Janeiro, CEP 21040-360, Brazil.
authors.forename: David W G
authors.initials: DW
authors.lastname: Brown
authors.affiliation: London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK.
authors.forename: Sara L
authors.initials: SL
authors.lastname: Thomas
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D004660:Encephalitis / Q000150:complications* / Q000453:epidemiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D011320:Primary Health Care / Q000706:statistics & numerical data; D012189:Retrospective Studies; D006113:United Kingdom / Q000453:epidemiology; D055815:Young Adult
keywords: Encephalitis; Epidemiology; Epilepsy; Outcomes; Sequelae