Saturday, 5 March 2016

On the question of suicide risk and chronic fatigue syndrome

The paper by Emmert Roberts and colleagues [1] (open-access) forms the basis of today's post and the finding that: "There was no significant difference in age-standardised and sex-standardised mortality ratios (SMRs) for all-cause mortality... or cancer-specific mortality in patients with chronic fatigue syndrome when compared with the general population in England and Wales." This is good news indeed bearing in mind how much a diagnosis of chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) can affect so many aspects of a person's life (see here).

The news about the diagnosis of CFS/ME not increasing 'all-cause mortality' is however tempered by the finding that author's results did show "a substantial increase in mortality from suicide"; something that has been picked up by some quarters of the media (see here). I might also direct readers to an accompanying commentary attached to the Roberts paper (see here).

The Roberts paper is open-access but a few points are worth highlighting.

Based on a participant group of over 2000 people diagnosed with CFS identified "using data from the South London and Maudsley NHS Foundation Trust Biomedical Research Centre (SLaM BRC) Clinical Record Interactive Search (CRIS) register", authors set about calculating mortality rates over a 7-year observation period (2007-2013). As per previous 'issues' on how a diagnosis of CFS is arrived at (see here) we are told that "the most inclusive criteria, and thus included all patients with a clinical diagnosis of chronic fatigue syndrome" were used.

Mortality details were cross-referenced with the participant group data initially "from the “Service User Death Report” of “the Spine”, maintained by NHS Care Records Service." Some further checking on the basis of the death certificate details and cross-referencing with ICD-10 codes "for cause of death" provided further details. Various other variables were also analysed including ethnicity, socio-economic status (SES) and the: "Presence of a lifetime diagnosis of depression was defined as having had a recorded depressive episode (ICD-10 code: F32.x) or recurrent depressive disorder (F33.x)."

Results: after some examination of the data authors "identified 2147 cases of chronic fatigue syndrome in CRIS with 17 deaths." Just over 1500 women were included for study and 11 of them had died (11/1533). Of 614 men included for study, 6 had died (6/614). Most deaths (n=8) were "from malignant neoplasm" but 5 deaths were recorded as suicide. Further: "When stratified by lifetime diagnosis of depression, 216 patients had a recorded lifetime diagnosis of F32.x or F33.x. Four (26%) of 17 patients who died had a lifetime diagnosis of depression, for two of whom the cause of death was suicide." The authors conclude that theirs is "the first study to show a specific increased risk of suicide in a population of patients with chronic fatigue syndrome compared with the general population." But also: "if there had been two fewer deaths by suicide, this risk would not be significantly increased."

Without belittling the tragedy that is suicide and the devastating impact it can have on a person's family and friends (as well as themselves), I do think it is worth reiterating a few cold, objective points. First, yes the suicide rate was heightened in this group over this period in comparison to population figures, but the overall number of cases was still low. Second, without making too many sweeping generalisations about depression, two of those five cases of suicide had a history of depression. Given the quite widely accepted greater vulnerability to suicide (attempted or actual) following a diagnosis of depression (see here), one could argue that a diagnosis of CFS/ME is potentially only coincidental to any such association. Other research has asked similar questions [2]. That is also if you assume that depression as a condition should not be included under the banner of ME/CFS [3]? Indeed reiterating that statement about 'if there were two fewer deaths by suicide, this risk would not be significantly increased' one *could* argue that the suicide rate in relation to CFS/ME is actually not increased with the depression findings taken into account. Finally, I'd also suggest that given the extent of the debilitating symptoms often associated with CFS/ME and the 'cruel' way that some/many people with CFS/ME have been treated down the years, the suicide rate reported by Roberts is perhaps lower than I think many people would have expected. Although not directly comparable with the Roberts data, suicide has been discussed on other occasions in the peer-reviewed domain with CFS/ME in mind [4].

Continuing: "This study highlights the importance of adequate assessment of mood and other psychiatric symptoms in patients with chronic fatigue syndrome, because lifetime diagnosis of depression is an independent risk factor for increased risk of completed suicide in this population. Although completed suicide was a rare event, the findings strengthen the case for robust psychiatric assessment by mental health professionals when managing individuals with chronic fatigue syndrome." I don't think anyone would quibble with the idea that a comprehensive assessment be provided to patients with ME/CFS given what is known about how psychology can be affected by the presentation of the condition (see here) and also that depression is not something to be taken lightly. I am however cautious of the idea that a 'robust psychiatric assessment' is the only thing offered to patients - "when managing" -  particularly when there is a wealth of peer-reviewed evidence on the more 'biological side' of the condition too (see here) with potentially important implications for treatment for example. I am, for example, going to be talking about the case report from Galán and colleagues [5] soon on how the "initial symptoms of mitochondrial disease in adults can easily be mistaken with CFS." Indeed, going back to that paper by Zdunke and colleagues [6] on how "there may be important differences in illness characteristics across individuals with CFS in the US and the UK, and this has implications for the comparability of research findings across these two countries" one might appreciate how much further the UK experience of CFS/ME needs to go in order to put biology and genetics on a research/clinical practice par with the influence of psychology and psychiatry in relation to the label.

And just in case you might not believe that CFS/ME can be a life-limiting condition, due respect should be paid to those who've paid the ultimate price as a result of their diagnosis.

For those who might need it, details of someone who will listen...

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[1] Roberts E. et al. Mortality of people with chronic fatigue syndrome: a retrospective cohort study in England and Wales from the South London and Maudsley NHS Foundation Trust Biomedical Research Centre (SLaM BRC) Clinical Record Interactive Search (CRIS) Register. Lancet. 2016. Feb 9.

[2] Fuller-Thomson E. & Nimigon J. Factors associated with depression among individuals with chronic fatigue syndrome: findings from a nationally representative survey. Fam Pract. 2008 Dec;25(6):414-22.

[3] Jason LA. et al. Unintended Consequences of not Specifying Exclusionary Illnesses for Systemic Exertion Intolerance Disease. Diagnostics (Basel). 2015 Jun 23;5(2):272-86.

[4] Jason LA. et al. Causes of death among patients with chronic fatigue syndrome. Health Care Women Int. 2006 Aug;27(7):615-26.

[5] Galán F. et al. Mitochondrial Myopathy in Follow-up of a Patient With Chronic Fatigue Syndrome. J Investig Med High Impact Case Rep. 2015 Sep 24;3(3):2324709615607908.

[6] Zdunek M. et al. A Cross Cultural Comparison of Disability and Symptomatology Associated with CFS. Int J Psychol Behav Sci. 2015;5(2):98-107.

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ResearchBlogging.org Roberts, E., Wessely, S., Chalder, T., Chang, C., & Hotopf, M. (2016). Mortality of people with chronic fatigue syndrome: a retrospective cohort study in England and Wales from the South London and Maudsley NHS Foundation Trust Biomedical Research Centre (SLaM BRC) Clinical Record Interactive Search (CRIS) Register The Lancet DOI: 10.1016/S0140-6736(15)01223-4