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Abstract
Objectives To compare mortality, comorbidities and causes of death in people with psychogenic non-epileptic seizures (PNES), epilepsy and the general population.
Methods Using linkage of multiple Swedish national registers, we identified individuals with incident diagnosis of PNES, epilepsy and conversion disorder with motor symptoms or deficits, and 10 controls for each. Main outcome was all-cause mortality. Causes of death were categorised into non-natural (eg, suicide, injuries) and natural. Conditional Cox regression models were used to estimate HRs and 95% CIs for mortality. HRs were adjusted for socioeconomic factors and psychiatric comorbidities.
Results Included were 885 individuals with PNES, 50 663 with epilepsy and 1057 with conversion disorder and motor symptoms or deficits. We found 32 (3.6%) deaths among individuals with PNES, compared with 46 (0.5%) deaths in controls, giving an adjusted HR of 5.5 (95% CI 2.8 to 10.8). Patients with epilepsy had a 6.7 times higher risk of death (95% CI 6.4 to 7.0) compared with individuals without epilepsy. The association between conversion disorder with motor symptoms or deficits was non-significant after adjusting for psychiatric comorbidities. PNES carried a higher risk of natural (HR 8.1, 95% CI 4.0 to 16.4) and non-natural causes of death (HR 15.3, 95% CI 3.0 to 78.6). Suicide ranked high in patients with PNES (18.8%) and conversion disorder with motor symptoms and deficits. The association between PNES diagnosis and all-cause mortality varied with age and time since diagnosis.
Conclusion Like epilepsy, PNES carries a higher than expected risk of both natural and non-natural causes of death. The high proportion of suicides requires further investigation.
- epilepsy
Data availability statement
Data sharing not applicable as no datasets generated and/or analysed for this study. The data used in this study are national register information made under ethical permission. The authors had no special privileges in accessing the data. Dissemination of personal information is regulated by the Swedish Secrecy Act. In accordance with Swedish law, researchers seeking access to individual-level data must apply for permission through a Research Ethics Board (etikprovningsmyndigheten.se) and from the National Board of Health and Welfare (socialstyrelsen.se/en/statistics-and-data/statistics/).
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Data availability statement
Data sharing not applicable as no datasets generated and/or analysed for this study. The data used in this study are national register information made under ethical permission. The authors had no special privileges in accessing the data. Dissemination of personal information is regulated by the Swedish Secrecy Act. In accordance with Swedish law, researchers seeking access to individual-level data must apply for permission through a Research Ethics Board (etikprovningsmyndigheten.se) and from the National Board of Health and Welfare (socialstyrelsen.se/en/statistics-and-data/statistics/).
Footnotes
Contributors ZC and LZ linked the data from the registries, performed statistical analyses and interpreted the data; EB helped with the discussion of the study findings and prepared the final version of the manuscript; MB performed the review of the literature, interpreted the data; LZ and MB wrote the first draft; TT conceived the project and critically appraised the data. GE made an intellectual contribution and helped with the refinement of the manuscript. ZC acts as guarantor.
Funding This study was funded by Swedish Research Council (2018-02213).
Competing interests EB reports grants from Italian Ministry of Health, grants from Swedish Orphan Biovitrum, personal fees from Arvelle Therapeutics, grants from American ALS Association, outside the submitted work. TT reports grants form EISAI, GSK, UCB, Bial, personal fees from EISAI, Sanofi, Sun Pharma, UCB, Sandoz, grants from EU, grants from Stockholm County Council, grants from CURE, outside the submitted work. The remaining authors have nothing to disclose.
Provenance and peer review Not commissioned; externally peer reviewed.
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