Correspondence
would be misplaced unless it is meant to describe the central government’s treatment of its exploitable citizens living at the periphery. I declare that I have no conflicts of interest.
Chris David Simms [email protected] Dalhousie University, Halifax, Nova Scotia B3H 1R2, Canada 1
2 3
4
5
Koplan J, Bond T, Merson M, et al. Towards a common definition of global health. Lancet 2009; 373: 1993–95. Horton R. Offline: is global health neocolonialist? Lancet 2013; 382: 1690. Foreign Affairs, Trade and Development Canada, News Releases. Harper government launches new international trade plan. http://www.international.gc.ca/media/comm/ news-communiques/2013/11/27a. aspx?lang=eng (accessed Jan 9, 2014). The Economist. Canada’s foreign policy: snubbed. Oct 14, 2010. http://www.economist. com/node/17254504 (accessed Dec 6, 2013). Jones N. Canada to investigate muzzling of scientists. Nature, April 2, 2013. http://blogs. nature.com/news/2013/04/canada-toinvestigate-muzzling-of-scientists.html (accessed Dec 6, 2013).
Premature mortality in patients with epilepsy We read with interest Seena Fazel and colleagues’ Article (Nov 16, p 1646)1 on premature mortality in epilepsy. Sleep disturbance has been reported to be more prevalent (twotimes more) in patients with partial epilepsy compared with controls, and most domains of sleep were substantially affected.2 In addition, sleep disturbance in individuals with epilepsy is associated with substantial impairment of quality of life.2 Interestingly, a meta-analysis showed that non-depressed patients with insomnia have a two-fold risk of developing depression compared with people with no sleep difficulties.3 In a cohort study of 75 000 Norwegians, sleeping problems were shown to be a marker of suicide risk, preponderantly due to the presence of sleeping problems and mixed anxiety and depression. 4 Consequently, neuropsychiatric disorders and sleep disruptions could have a common 510
mechanistic origin. 5 Therefore, we wonder whether Fazel and colleagues1 have collected data about sleep disturbances in their sample. Furthermore, functional imaging of the brain (eg, PET) could help us to understand suicidal behaviour in more detail. Maybe there is a suicidal brain independent of concomitant diseases or a specific disease (eg, epilepsy) that triggers a pattern of suicidal brain dysfunction. We declare that we have no conflicts of interest.
*Andreas Otte, Dieter Riemann andreas.otte@hs-offenburg.de Biomedical Engineering, University of Applied Sciences, D-77652 Offenburg, Germany (AO); and Department of Clinical Psychophysiology, Hospital for Psychiatry and Psychotherapy, University Medical Center, Freiburg, Germany (DR) 1
2
3
4
5
Fazel S, Wolf A, Långström N, Newton CR, Lichtenstein P. Premature mortality in epilepsy and the role of psychiatric comorbidity: a total population study. Lancet 2013; 382: 1646–54. De Weerd A, De Haas S, Otte A, et al. Subjective sleep disturbance in patients with partial seizures and impact on quality of life: a questionnaire-based study. Epilepsia 2004; 45: 1397–404. Baglioni C, Battagliese G, Feige B, et al. Insomnia as a predictor of depression: a meta-analytic evaluation of longitudinal epidemiological studies. J Affect Disord 2011; 135: 10–19. Bjørngaard JH, Bjerkeset O, Romundstad P, Gunnell D. Sleeping problems and suicide in 75 000 Norwegian adults: a 20 year follow-up of the HUNT I study. Sleep 2011; 34: 1155–59. Wulff K, Gatti S, Wettstein JG, Foster RG. Sleep and circadian rhythm disruption in psychiatric and neurodegenerative disease. Nat Rev Neurosci 2010; 11: 589–99.
We commend Seena Fazel and colleagues1 on their study highlighting the risk of premature death in people with epilepsy and the role of psychiatric comorbidity in increasing this mortality. Although the observed odds ratio for premature mortality was similar to that in a previous study using similar methods,2 we wonder to what extent the mortality estimates were inflated by inclusion of status epilepticus in the epilepsy cohort. In most cases, status epilepticus is a symptom of an acute brain insult (ie, stroke, anoxia) and does not fulfil criteria for epilepsy.3 Such cases of status epilepticus have a high
mortality, related to the underlying cause. 3,4 It would be interesting to know the proportion of cases with status epilepticus in Fazel and colleagues’ cohort and whether their exclusion would alter mortality estimates. Fazel and colleagues1 found that compared with controls without epilepsy or psychiatric disorders, psychiatric comorbidity in epilepsy was associated with an increased mortality overall and specifically for suicide and accidents. The presence of multiplicative or additive interaction between epilepsy and psychiatric disorder was not addressed. Our calculations find synergy between substance misuse and epilepsy for external causes of death, suicide, and vehicle accidents, but not for other accidents. Negative multiplicative interaction was noted for all other associations. On the additive scale most associations between epilepsy and any psychiatric disorder, depression and substance misuse showed positive additive interactions for external causes of death, suicide, and vehicle accidents. This suggests that public health interventions are needed to reduce these specific deaths. We declare that we have no conflicts of interest.
*Torbjörn Tomson, Dale C Hesdorffer [email protected] Department of Clinical Neuroscience, Karolinska Institutet, SE 171 76 Stockholm, Sweden (TT); and Gertrude H Sergievksy Center and Department of Epidemiology, Columbia University, New York, NY, USA (DCH) 1
2
3
4
Fazel S, Wolf A, Långström N, Newton CR, Lichtenstein P. Premature mortality in epilepsy and the role of psychiatric comorbidity: a total population study. Lancet 2013; 382: 1646–54. Nilsson L, Tomson T, Farahmand BY, Diwan V, Persson PG. Cause-specific mortality in epilepsy: a cohort study of more than 9 000 patients once hospitalized for epilepsy. Epilepsia 1997; 38: 1062–68. Neligan A, Shorvon S. Frequency and prognosis of convulsive status epilepticus of different causes. Arch Neurol 2010; 67: 931–40. Logroscino G, Hesdorffer DC, Cascino G, Annegers JF, Hauser WA. Short-term mortality after a first episode of status epilepticus. Epilepsia 1997; 38: 1344–49.
www.thelancet.com Vol 383 February 8, 2014
would be misplaced unless it is meant to describe the central government’s treatment of its exploitable citizens living at the periphery. I declare that I have no conflicts of interest.
Chris David Simms [email protected] Dalhousie University, Halifax, Nova Scotia B3H 1R2, Canada 1
2 3
4
5
Koplan J, Bond T, Merson M, et al. Towards a common definition of global health. Lancet 2009; 373: 1993–95. Horton R. Offline: is global health neocolonialist? Lancet 2013; 382: 1690. Foreign Affairs, Trade and Development Canada, News Releases. Harper government launches new international trade plan. http://www.international.gc.ca/media/comm/ news-communiques/2013/11/27a. aspx?lang=eng (accessed Jan 9, 2014). The Economist. Canada’s foreign policy: snubbed. Oct 14, 2010. http://www.economist. com/node/17254504 (accessed Dec 6, 2013). Jones N. Canada to investigate muzzling of scientists. Nature, April 2, 2013. http://blogs. nature.com/news/2013/04/canada-toinvestigate-muzzling-of-scientists.html (accessed Dec 6, 2013).
Premature mortality in patients with epilepsy We read with interest Seena Fazel and colleagues’ Article (Nov 16, p 1646)1 on premature mortality in epilepsy. Sleep disturbance has been reported to be more prevalent (twotimes more) in patients with partial epilepsy compared with controls, and most domains of sleep were substantially affected.2 In addition, sleep disturbance in individuals with epilepsy is associated with substantial impairment of quality of life.2 Interestingly, a meta-analysis showed that non-depressed patients with insomnia have a two-fold risk of developing depression compared with people with no sleep difficulties.3 In a cohort study of 75 000 Norwegians, sleeping problems were shown to be a marker of suicide risk, preponderantly due to the presence of sleeping problems and mixed anxiety and depression. 4 Consequently, neuropsychiatric disorders and sleep disruptions could have a common 510
mechanistic origin. 5 Therefore, we wonder whether Fazel and colleagues1 have collected data about sleep disturbances in their sample. Furthermore, functional imaging of the brain (eg, PET) could help us to understand suicidal behaviour in more detail. Maybe there is a suicidal brain independent of concomitant diseases or a specific disease (eg, epilepsy) that triggers a pattern of suicidal brain dysfunction. We declare that we have no conflicts of interest.
*Andreas Otte, Dieter Riemann andreas.otte@hs-offenburg.de Biomedical Engineering, University of Applied Sciences, D-77652 Offenburg, Germany (AO); and Department of Clinical Psychophysiology, Hospital for Psychiatry and Psychotherapy, University Medical Center, Freiburg, Germany (DR) 1
2
3
4
5
Fazel S, Wolf A, Långström N, Newton CR, Lichtenstein P. Premature mortality in epilepsy and the role of psychiatric comorbidity: a total population study. Lancet 2013; 382: 1646–54. De Weerd A, De Haas S, Otte A, et al. Subjective sleep disturbance in patients with partial seizures and impact on quality of life: a questionnaire-based study. Epilepsia 2004; 45: 1397–404. Baglioni C, Battagliese G, Feige B, et al. Insomnia as a predictor of depression: a meta-analytic evaluation of longitudinal epidemiological studies. J Affect Disord 2011; 135: 10–19. Bjørngaard JH, Bjerkeset O, Romundstad P, Gunnell D. Sleeping problems and suicide in 75 000 Norwegian adults: a 20 year follow-up of the HUNT I study. Sleep 2011; 34: 1155–59. Wulff K, Gatti S, Wettstein JG, Foster RG. Sleep and circadian rhythm disruption in psychiatric and neurodegenerative disease. Nat Rev Neurosci 2010; 11: 589–99.
We commend Seena Fazel and colleagues1 on their study highlighting the risk of premature death in people with epilepsy and the role of psychiatric comorbidity in increasing this mortality. Although the observed odds ratio for premature mortality was similar to that in a previous study using similar methods,2 we wonder to what extent the mortality estimates were inflated by inclusion of status epilepticus in the epilepsy cohort. In most cases, status epilepticus is a symptom of an acute brain insult (ie, stroke, anoxia) and does not fulfil criteria for epilepsy.3 Such cases of status epilepticus have a high
mortality, related to the underlying cause. 3,4 It would be interesting to know the proportion of cases with status epilepticus in Fazel and colleagues’ cohort and whether their exclusion would alter mortality estimates. Fazel and colleagues1 found that compared with controls without epilepsy or psychiatric disorders, psychiatric comorbidity in epilepsy was associated with an increased mortality overall and specifically for suicide and accidents. The presence of multiplicative or additive interaction between epilepsy and psychiatric disorder was not addressed. Our calculations find synergy between substance misuse and epilepsy for external causes of death, suicide, and vehicle accidents, but not for other accidents. Negative multiplicative interaction was noted for all other associations. On the additive scale most associations between epilepsy and any psychiatric disorder, depression and substance misuse showed positive additive interactions for external causes of death, suicide, and vehicle accidents. This suggests that public health interventions are needed to reduce these specific deaths. We declare that we have no conflicts of interest.
*Torbjörn Tomson, Dale C Hesdorffer [email protected] Department of Clinical Neuroscience, Karolinska Institutet, SE 171 76 Stockholm, Sweden (TT); and Gertrude H Sergievksy Center and Department of Epidemiology, Columbia University, New York, NY, USA (DCH) 1
2
3
4
Fazel S, Wolf A, Långström N, Newton CR, Lichtenstein P. Premature mortality in epilepsy and the role of psychiatric comorbidity: a total population study. Lancet 2013; 382: 1646–54. Nilsson L, Tomson T, Farahmand BY, Diwan V, Persson PG. Cause-specific mortality in epilepsy: a cohort study of more than 9 000 patients once hospitalized for epilepsy. Epilepsia 1997; 38: 1062–68. Neligan A, Shorvon S. Frequency and prognosis of convulsive status epilepticus of different causes. Arch Neurol 2010; 67: 931–40. Logroscino G, Hesdorffer DC, Cascino G, Annegers JF, Hauser WA. Short-term mortality after a first episode of status epilepticus. Epilepsia 1997; 38: 1344–49.
www.thelancet.com Vol 383 February 8, 2014
