Category: Epidemiology

Suicide risk in people with chronic fatigue syndrome

The risk of dying is increased in many illnesses, but the mortality associated with chronic fatigue syndrome is relatively unexplored. In The Lancet, Emmert Roberts and colleagues1 report results from a case register study that linked the clinical details of more than 2000 people with chronic fatigue syndrome presenting to a specialist clinic (in London and the south of England) with mortality outcomes over 7 years. This is the largest study of its type so far, and used a robust case definition. The researchers noted that the overall risk of death in patients with chronic fatigue syndrome seemed no different from the risk in the general population. Cancer mortality was also similar. However, the findings for suicide deaths were striking—five people died during the 7-year period. Based on the suicide rate in the general population of England and Wales, the expected number would have been less than one death by suicide. In other words, suicide risk was increased almost seven-fold. A previous US study2 reported an increase in suicide mortality in people with fatigue symptoms, but was too small to show an increased suicide risk in those who met the criteria for chronic fatigue syndrome.

The results of the current study are potentially very important but need to be interpreted with caution. The study was quite small for an investigation of mortality (n=2147 patients of whom 17 died). This small sample meant that the stratified analyses in particular (investigation of the risk of death in sex, age, diagnostic, and deprivation subgroups) lacked statistical power. The increased suicide mortality (sex-standardised mortality ratio 6·85, 95% CI 2·22–15·98; p=0·002) was based on just a few deaths and the confidence intervals were wide. Two fewer suicide deaths would have meant that the findings were no longer significant.

The cohort itself was well defined but consisted of people who attended a national specialist centre run jointly by general medical and mental health service providers. This could mean that participants were representative of people with more severe or complex chronic fatigue syndrome, and the mortality findings might not be applicable to people with the disorder in primary care.

Read the rest of this comment here: http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(16)00270-1/fulltext

Comment on

Source: Kapur N, Webb R. Suicide risk in people with chronic fatigue syndrome. Lancet. 2016 Apr 16;387(10028):1596-7. doi: 10.1016/S0140-6736(16)00270-1. Epub 2016 Feb 10. http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(16)00270-1/fulltext (Full article)

 

 

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

Abstract:

BACKGROUND: Mortality associated with chronic fatigue syndrome is uncertain. We investigated mortality in individuals diagnosed with chronic fatigue syndrome in secondary and tertiary care using data from the South London and Maudsley NHS Foundation Trust Biomedical Research Centre (SLaM BRC) Clinical Record Interactive Search (CRIS) register.

METHODS: We calculated standardised mortality ratios (SMRs) for all-cause, suicide-specific, and cancer-specific mortality for a 7-year observation period using the number of deaths observed in SLaM records compared with age-specific and sex-specific mortality statistics for England and Wales. Study participants were included if they had had contact with the chronic fatigue service (referral, discharge, or case note entry) and received a diagnosis of chronic fatigue syndrome.

FINDINGS: We identified 2147 cases of chronic fatigue syndrome from CRIS and 17 deaths from Jan 1, 2007, to Dec 31, 2013. 1533 patients were women of whom 11 died, and 614 were men of whom six died. There was no significant difference in age-standardised and sex-standardised mortality ratios (SMRs) for all-cause mortality (SMR 1·14, 95% CI 0·65-1·85; p=0·67) or cancer-specific mortality (1·39, 0·60-2·73; p=0·45) in patients with chronic fatigue syndrome when compared with the general population in England and Wales. This remained the case when deaths from suicide were removed from the analysis. There was a significant increase in suicide-specific mortality (SMR 6·85, 95% CI 2·22-15·98; p=0·002).

INTERPRETATION: We did not note increased all-cause mortality in people with chronic fatigue syndrome, but our findings show a substantial increase in mortality from suicide. This highlights the need for clinicians to be aware of the increased risk of completed suicide and to assess suicidality adequately in patients with chronic fatigue syndrome.

FUNDING: National Institute for Health Research (NIHR) Biomedical Research Centre at South London and Maudsley NHS Foundation Trust and King’s College London.

Copyright © 2016 Roberts et al. Open Access article distributed under the terms of CC BY. Published by Elsevier Ltd.. All rights reserved.

 

Source: Roberts E, Wessely S, Chalder T, Chang CK, Hotopf M. 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 Apr 16;387(10028):1638-43. doi: 10.1016/S0140-6736(15)01223-4. Epub 2016 Feb 10. http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(15)01223-4/fulltext (Full article)

Comment in

 

Increased risk of chronic fatigue syndrome in patients with migraine: A retrospective cohort study

Abstract:

OBJECTIVE: The common concurrence of migraine and chronic fatigue syndrome (CFS) has been reported but whether migraine poses a higher risk of CFS remains unknown. In this retrospective case-control study, we examined the association between the 2 disorders by using a nationwide, population-based database in Taiwan.

METHODS: The data were retrieved and analyzed from the National Health Insurance Research Database (NHIRD) of Taiwan; 6902 newly diagnosed migraine cases from 2006-2010 were identified in a subset of the NHIRD, and 27,608 migraine-free individuals were randomly selected as the comparison cohort. The multivariate Cox proportional hazards regression model was used to investigate the risk of CFS in migraineurs after adjustment for demographic characteristics and comorbidities.

RESULTS: After adjustment for the covariates, the risk of CFS was 1.5-fold higher in the migraine cohort than in the comparison cohort (52.72 vs. 28.85 per 10,000 person-years). Intriguingly, the risk was most prominent in the oldest group (≥ 65 years), with a 2.11-fold increased risk (95% confidence interval 1.31-3.41) of CFS. In addition, the adjusted cumulative incidence of CFS in the follow-up years was higher in the migraine group (log-rank test, P < .0001), and CFS incidence appeared to increase with the frequency of migraine diagnoses.

CONCLUSION: The current study demonstrated an increased risk of CFS in migraineurs. Proposed mechanisms in previous studies such as mitochondrial dysfunction and central sensitization may underlie the shared pathophysiology of these seemingly distinct but potentially overlapping disorders.

Copyright © 2015 Elsevier Inc. All rights reserved.

 

Source: Lau CI, Lin CC, Chen WH, Wang HC, Kao CH. Increased risk of chronic fatigue syndrome in patients with migraine: A retrospective cohort study. J Psychosom Res. 2015 Dec;79(6):514-8. doi: 10.1016/j.jpsychores.2015.10.005. Epub 2015 Oct 20. https://www.ncbi.nlm.nih.gov/pubmed/26505533

 

Chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) is associated with pandemic influenza infection, but not with an adjuvanted pandemic influenza vaccine

Abstract:

BACKGROUND: Chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) is associated to infections and it has been suggested that vaccination can trigger the disease. However, little is known about the specific association between clinically manifest influenza/influenza vaccine and CFS/ME. As part of a registry surveillance of adverse effects after mass vaccination in Norway during the 2009 influenza A (H1N1) pandemic, we had the opportunity to estimate and contrast the risk of CFS/ME after infection and vaccination.

METHODS: Using the unique personal identification number assigned to everybody who is registered as resident in Norway, we followed the complete Norwegian population as of October 1, 2009, through national registries of vaccination, communicable diseases, primary health, and specialist health care until December 31, 2012. Hazard ratios (HRs) of CFS/ME, as diagnosed in the specialist health care services (diagnostic code G93.3 in the International Classification of Diseases, Version 10), after influenza infection and/or vaccination were estimated using Cox proportional-hazards regression.

RESULTS: The incidence rate of CFS/ME was 2.08 per 100,000 person-months at risk. The adjusted HR of CFS/ME after pandemic vaccination was 0.97 (95% confidence interval [CI]: 0.91-1.04), while it was 2.04 (95% CI: 1.78-2.33) after being diagnosed with influenza infection during the peak pandemic period.

CONCLUSIONS: Pandemic influenza A (H1N1) infection was associated with a more than two-fold increased risk of CFS/ME. We found no indication of increased risk of CFS/ME after vaccination. Our findings are consistent with a model whereby symptomatic infection, rather than antigenic stimulation may trigger CFS/ME.

Copyright © 2015 Elsevier Ltd. All rights reserved.

 

Source: Magnus P, Gunnes N, Tveito K, Bakken IJ, Ghaderi S, Stoltenberg C, Hornig M, Lipkin WI, Trogstad L, Håberg SE. Chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) is associated with pandemic influenza infection, but not with an adjuvanted pandemic influenza vaccine. Vaccine. 2015 Nov 17;33(46):6173-7. doi: 10.1016/j.vaccine.2015.10.018. Epub 2015 Oct 17. https://www.ncbi.nlm.nih.gov/pubmed/26475444

 

Increased Risk of Chronic Fatigue Syndrome Following Atopy: A Population-Based Study

Abstract:

Several hypotheses have been proposed to explain the etiopathogenesis of chronic fatigue syndrome (CFS), including immune dysregulation. However, few population-based prospective cohort studies have been conducted on CFS and atopy.

We investigated the relationship between atopy and CFS by using a population-based cohort study. In this prospective, population-based cohort study of the National Health Insurance Research Database, we identified 42,558 patients with atopy and 170,232 patients without atopy from 2005 to 2007 with follow-up to 2011. The incidence rates and risks for CFS were estimated using Cox proportion hazards regression.

The overall incidence rate of CFS was higher in the atopy cohort compared with the nonatopy cohort (1.37 versus 0.87 per 1000 person-year), with an adjusted hazard ratio of 1.48 (95% confidence interval 1.30-1.69). The risk of CFS in the atopy cohort increased 1.47- to 1.50-fold for each nonexisting comorbidity. Patients with numerous atopic symptoms exhibited a biological gradient of increasing risk for CFS, and the risk changed significantly after adjustment for age, sex, and comorbidities, increasing from 1.46- to 2.59-fold.

We revealed that atopy is associated with CFS, particularly in patients with numerous atopic syndromes. The actual mechanism for CFS development in patients with atopy remains unclear and requires further investigation. We recommend researching the subsequent fatigue symptom in patients with atopy, particularly those with multiple atopic syndromes.

 

Source: Yang TY, Kuo HT, Chen HJ, Chen CS, Lin WM, Tsai SY, Kuo CN, Kao CH. Increased Risk of Chronic Fatigue Syndrome Following Atopy: A Population-Based Study. Medicine (Baltimore). 2015 Jul;94(29):e1211. doi: 10.1097/MD.0000000000001211. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4603016/ (Full article)

 

Chronic fatigue syndrome: Features of a population of patients from northern Italy

Abstract:

In this study we analyzed the clinical features of a population of Italian patients with chronic fatigue syndrome (CFS) diagnosed according to the CDC-1994 criteria. The aim was to investigate CFS patients and their relatives, in order to search for events related to the onset of the disease and to identify correlations with other diseases. The analysis was carried out by examining medical records belonging to 82 patients suffering from the syndrome. The documentation was collected between 2008 and 2011 and provided by the non-profit Italian organization AMCFS (Associazione Malati di CFS). The influence of gender on the age of onset and association with potential risk factors were investigated in patients and in their relatives. From the results a significant correlation between the age of onset and autoimmunity was observed.

© The Author(s) 2015.

 

Source: Capelli E, Lorusso L, Ghitti M, Venturini L, Cusa C, Ricevuti G. Chronic fatigue syndrome: Features of a population of patients from northern Italy. Int J Immunopathol Pharmacol. 2015 Mar;28(1):53-9. Doi: 10.1177/0394632015572074. https://www.ncbi.nlm.nih.gov/pubmed/25816406

 

Chronic fatigue syndrome and fibromyalgia in Canada: prevalence and associations with six health status indicators

Abstract:

INTRODUCTION: Few studies have considered the factors independently associated with chronic fatigue syndrome (CFS) and/or fibromyalgia (FM) or considered the impact of these conditions on health status using population-based data.

METHODS: We used data from the nationally representative 2010 Canadian Community Health Survey (n = 59 101) to describe self-reported health professional-diagnosed CFS and/or FM, and their associations with 6 health status indicators.

RESULTS: In 2010, diagnosed CFS and FM are reported by 1.4% (95% confidence interval [CI]: 1.3%-1.6%) and 1.5% (1.4%-1.7%), respectively, of the Canadian household population aged 12 years and over, with comorbid CFS and FM affecting 0.3% (0.3%-0.4%) of that population. Prevalent CFS and/or FM were more common among women, adults aged 40 years and over, those with lowest income, and those with certain risk factors for chronic disease (i.e. obesity, physical inactivity and smoking). After controlling for differences between the groups, people with CFS and/or FM reported poorer health status than those with neither condition on 5 indicators of health status, but not on the measure of fair/poor mental health. Having both CFS and FM and having multiple comorbid conditions was associated with poorer health status.

CONCLUSION: Co-occurrence of CFS and FM and having other chronic conditions were strongly related to poorer health status and accounted for much of the differences in health status. Understanding factors contributing to improved quality of life in people with CFS and/or FM, particularly in those with both conditions and other comorbidities, may be an important area for future research.

 

Source: Rusu C, Gee ME, Lagacé C, Parlor M. Chronic fatigue syndrome and fibromyalgia in Canada: prevalence and associations with six health status indicators. Health Promot Chronic Dis Prev Can. 2015 Mar;35(1):3-11. [Article in English, French; Abstract available in French from the publisher] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4939456/ (Full article)

 

Two age peaks in the incidence of chronic fatigue syndrome/myalgic encephalomyelitis: a population-based registry study from Norway 2008-2012

Abstract:

BACKGROUND: The aim of the current study was to estimate sex- and age-specific incidence rates of chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) using population-based registry data. CFS/ME is a debilitating condition with large impact on patients and their families. The etiology is unknown, and the distribution of the disease in the general population has not been well described.

METHODS: Cases of CFS/ME were identified in the Norwegian Patient Register (NPR) for the years 2008 to 2012. The NPR is nationwide and contains diagnoses assigned by specialist health care services (hospitals and outpatient clinics). We estimated sex- and age-specific incidence rates by dividing the number of new cases of CFS/ME in each category by the number of person years at risk. Incidence rate ratios were estimated by Poisson regression with sex, age categories, and year of diagnosis as covariates.

RESULTS: A total of 5,809 patients were registered with CFS/ME during 2008 to 2012. The overall incidence rate was 25.8 per 100,000 person years (95% confidence interval (CI): 25.2 to 26.5). The female to male incidence rate ratio of CFS/ME was 3.2 (95% CI: 3.0 to 3.4). The incidence rate varied strongly with age for both sexes, with a first peak in the age group 10 to 19 years and a second peak in the age group 30 to 39 years.

CONCLUSIONS: Early etiological clues can sometimes be gained from examination of disease patterns. The strong female preponderance and the two age peaks suggest that sex- and age-specific factors may modulate the risk of CFS/ME.

 

Source: Bakken IJ, Tveito K, Gunnes N, Ghaderi S, Stoltenberg C, Trogstad L, Håberg SE, Magnus P. Two age peaks in the incidence of chronic fatigue syndrome/myalgic encephalomyelitis: a population-based registry study from Norway 2008-2012. BMC Med. 2014 Oct 1;12:167. doi: 10.1186/s12916-014-0167-5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4189623/ (full article)

Comment:

Increased risk of chronic fatigue syndrome following herpes zoster: a population-based study

Erratum in

  • Eur J Clin Microbiol Infect Dis. 2014 Sep;33(9):1661.

Abstract:

Chronic fatigue syndrome (CFS) is a complex disorder accompanied by unexplainable persistent fatigue, in which several etiological factors exist, such as viral infections. Using the National Health Insurance Research Database (NHIRD) of Taiwan, this study evaluated the association between herpes zoster (HZ) infection and the risk of CFS, and examined the possibility of patients developing postviral fatigue effects, including the possibility of developing other unexplainable chronic fatigue conditions.

In this prospective cohort study using the NHIRD, we identified 9,205 patients with HZ infection [ICD-9 (International Classification of Disease, Ninth Revision), code 053] and 36,820 patients without HZ infection (non-HZ) from 2005 to 2007, and followed up to the end of 2010. The incidence rate of CFS was higher in the HZ cohort than in the non-HZ cohort (4.56 vs. 3.44 per 1,000 person-years), with an adjusted hazard ratio of 1.29 [95 % confidence interval (CI) = 1.09-1.53]. It was shown that the risk of CFS without comorbidity for each patient increased from 1.25- to 1.36-fold between the CFS and non-CFS cohorts; with long-term follow-up, the HZ cohort showed a significantly higher cumulative incidence rate of developing CFS than the non-HZ patients.

We propose that patients with chronic fatigue might exist in a subset of patients that would be associated with HZ infection. The actual mechanism of development of CFS that is attributed to HZ infection remains unclear. The findings of this population cohort study provide pivotal evidence of postviral fatigue among patients with HZ infection.

 

Source: Tsai SY, Yang TY, Chen HJ, Chen CS, Lin WM, Shen WC, Kuo CN, Kao CH. Increased risk of chronic fatigue syndrome following herpes zoster: a population-based study. Eur J Clin Microbiol Infect Dis. 2014 Sep;33(9):1653-9. doi: 10.1007/s10096-014-2095-x. Epub 2014 Apr 9. https://www.ncbi.nlm.nih.gov/pubmed/24715153

 

Predictors of Post-Infectious Chronic Fatigue Syndrome in Adolescents

Abstract:

This study focused on identifying risk factors for adolescent post-infectious chronic fatigue syndrome (CFS), utilizing a prospective, nested case-control longitudinal design in which over 300 teenagers with Infectious Mononucleosis (IM) were identified through primary care sites and followed.

Baseline variables that were gathered several months following IM, included autonomic symptoms, days in bed since IM, perceived stress, stressful life events, family stress, difficulty functioning and attending school, family stress and psychiatric disorders. A number of variables were predictors of post-infectious CFS at 6 months; however, when autonomic symptoms were used as a control variable, only days spent in bed since mono was a significant predictor. Step-wise logistic regression findings indicated that baseline autonomic symptoms as well as days spent in bed since mono, which reflect the severity of illness, were the only significant predictors of those who met CFS criteria at 6 months.

 

Source: Jason LA, Katz BZ, Shiraishi Y, Mears CJ, Im Y, Taylor R. Predictors of Post-Infectious Chronic Fatigue Syndrome in Adolescents. Health Psychol Behav Med. 2014 Jan 1;2(1):41-51. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3956649/ (Full article)