Tag: White

An empirical delineation of the heterogeneity of chronic unexplained fatigue in women

Abstract:

OBJECTIVES: To test the hypothesis that medically unexplained chronic fatigue and chronic fatigue syndrome (CFS) are heterogeneous conditions, and to define the different conditions using both symptom and laboratory data.

METHODS: We studied 159 women from KS, USA. A total of 51 of these suffered from fatigue consistent with established criteria for CFS, 55 had chronic fatigue of insufficient symptoms/severity for a CFS diagnosis and 53 were healthy controls matched by age and body mass index (BMI) against those with CFS. We used principal components analyses to define factors that best described the variable space and to reduce the number of variables. The 38 most explanatory variables were then used in latent class analyses to define discrete subject groups.

RESULTS: Principal components analyses defined six discrete factors that explained 40% of the variance. Latent class analyses provided several interpretable solutions with four, five and six classes. The four-class solution was statistically most convincing, but the six-class solution was more interpretable. Class 1 defined 41 (26%) subjects with obesity and relative sleep hypnoea. Class 2 were 38 (24%) healthy subjects. Class 3 captured 24 (15%) obese relatively hypnoeic subjects, but with low heart rate variability and cortisol. Class 4 were 23 (14%) sleep-disturbed and myalgic subjects without obesity or significant depression. The two remaining classes with 22 (14%) and 11 (7%) subjects consisted of the most symptomatic and depressed, but without obesity or hypnoea. Class 5 had normal sleep indices. Class 6 was characterized by disturbed sleep, with low sleep heart rate variability, cortisol, and sex hormones.

CONCLUSION: Chronic medically unexplained fatigue is heterogeneous. The putative syndromes were differentiated by obesity, sleep hypnoea, depression, physiological stress response, sleep disturbance, interoception and menopausal status. If these syndromes are externally validated and replicated, they may prove useful in determining the causes, pathophysiology and treatments of CFS.

 

Source: Vollmer-Conna U, Aslakson E, White PD. An empirical delineation of the heterogeneity of chronic unexplained fatigue in women. Pharmacogenomics. 2006 Apr;7(3):355-64. https://www.ncbi.nlm.nih.gov/pubmed/16610946

 

Is the chronic fatigue syndrome an exercise phobia? A case control study

Abstract:

OBJECTIVE: The aim of this study was to test whether patients with chronic fatigue syndrome (CFS) have an exercise phobia, by measuring anxiety-related physiological and psychological reactions to ordinary activity and exercise.

METHODS: Patients and healthy but sedentary controls were assessed over 8 h of an ordinary day, and before, during and after an incremental exercise test on a motorised treadmill. To avoid confounding effects, those with a comorbid psychiatric disorder were excluded. Heart rate, galvanic skin resistance (GSR) and the amount of activity undertaken were measured, along with state and trait measures of anxiety.

RESULTS: Patients with CFS were more fatigued and sleep disturbed than were the controls and noted greater effort during the exercise test. No statistically significant differences were found in either heart rate or GSR both during a normal day and before, during and after the exercise test. Patients with CFS were more symptomatically anxious at all times, but this did not increase with exercise.

CONCLUSION: The data suggest that CFS patients without a comorbid psychiatric disorder do not have an exercise phobia.

 

Source: Gallagher AM, Coldrick AR, Hedge B, Weir WR, White PD. Is the chronic fatigue syndrome an exercise phobia? A case control study. J Psychosom Res. 2005 Apr;58(4):367-73. http://www.ncbi.nlm.nih.gov/pubmed/15992572

 

The prognosis of different fatigue diagnostic labels: a longitudinal survey

Abstract:

BACKGROUND: Several different diagnostic labels exist for the fatigue syndromes, including chronic fatigue syndrome (CFS), myalgic encephalomyelitis (ME) and postviral fatigue syndrome (PVFS). An allied condition is fibromyalgia. No study has examined prognostic differences across these different labels.

OBJECTIVE: To compare the prognoses of patients labelled with different fatigue syndromes in primary care.

METHODS: We performed a longitudinal survey, using electronic records from the General Practice Research Database. All 18,122 patients diagnosed by their GP with a fatigue syndrome from 1988-2001 with a minimum of one year of records after diagnosis were collated into four groups: CFS, ME, PVFS and fibromyalgia. CFS and ME were combined for the main analysis as no code for CFS was available until 1995. The length of illness was calculated as the interval between the diagnosis and the last recorded fatigue symptom, expressed as days per year, to account for differing lengths of record after diagnosis.

RESULTS: Patients with CFS/ME combined had a worse prognosis (median length of illness 80 days per year; interquartile range 0-242) than fibromyalgia (51; 0-244) or PVFS 0 (0-108), a significant difference, P < 0.001. In a subgroup analysis, ME had a worse prognosis (median length of illness in days per year 106; interquartile range 0-259) than CFS (33; 0-170), P < 0.001, in spite of a better course before diagnosis. Secondary outcome measures were consistent with these results.

CONCLUSION: There were important differences in outcome between the various fatigue labels, with ME having the worst prognosis and PVFS the best. This could be an adverse effect of the label ME itself. Alternatively, patients who are destined to have a worse prognosis may preferentially attract the ME label. Our data support the first interpretation.

 

Source: Hamilton WT, Gallagher AM, Thomas JM, White PD. The prognosis of different fatigue diagnostic labels: a longitudinal survey. Fam Pract. 2005 Aug;22(4):383-8. Epub 2005 Apr 1. http://fampra.oxfordjournals.org/content/22/4/383.long (Full article)

 

Subjective quality of life in patients with chronic fatigue syndrome

Abstract:

The aim of this study was to (1) assess Subjective Quality of Life (SQOL) of patients with Chronic Fatigue Syndrome (CFS) using a generic concept and to compare the findings with those in groups with mental disorders and healthy subjects, and (2) investigate whether and, if so, to what extent socio-demographic and clinical variables predict SQOL in CFS patients.

Seventy-three patients diagnosed with CFS were randomly selected and interviewed from two specialised clinics. CFS was diagnosed using the Oxford Criteria. SQOL was assessed on the Manchester Short Assessment of Quality of Life (MANSA) and Health-Related Quality of Life (HRQOL) on the Medical Outcome Study Short-Form 36 (MOS) SF-36. A battery of mood and symptom questionnaires, including the Symptom Checklist Questionnaire (SCL-90-R), was administered to assess various aspects of symptomatology as potential predictor variables.

Multiple regression analyses were conducted to identify predictors of SQOL. Overall, SQOL was low in CFS patients and less favourable than in groups with mental disorders and healthy subjects. Satisfaction was particularly low with life as a whole, leisure activities and financial situation. Whilst SQOL was only moderately correlated with HRQOL, the SCL-90-R score, especially SCL-90-R Depression scale score, was the best predictor of SQOL explaining 35% of the variance. HRQOL and generic SQOL appear distinct despite some overlap.

The findings underline that SQOL is significantly disrupted in CFS patients. Depressive symptoms are statistically the strongest ‘predictor’ of SQOL, although the direction of the relationship is not established. These data suggest that treatment of depression associated with CFS, regardless of causation, could help to improve SQOL in CFS patients.

 

Source: Rakib A, White PD, Pinching AJ, Hedge B, Newbery N, Fakhoury WK, Priebe S. Subjective quality of life in patients with chronic fatigue syndrome. Qual Life Res. 2005 Feb;14(1):11-9. http://www.ncbi.nlm.nih.gov/pubmed/15789937

 

Incidence of fatigue symptoms and diagnoses presenting in UK primary care from 1990 to 2001

Erratum in: J R Soc Med. 2005 Feb;98(2):88.

 

Abstract:

Little is known about whether the incidence of symptoms of fatigue presented in primary care, and the consequent diagnoses made, change over time. The UK General Practice Research Database was used to investigate the annual incidence of both fatigue symptoms and diagnoses recorded in UK primary care from 1990 to 2001. The overall incidence of all fatigue diagnoses decreased from 87 per 100 000 patients in 1990 to 49 in 2001, a reduction of 44%, while postviral fatigue syndromes decreased from 81% of all fatigue diagnoses in 1990 to 60% in 2001. Chronic fatigue syndrome (CFS) and myalgic encephalomyelitis (ME) together increased from 9% to 26% of all fatigue diagnoses. The incidence of fibromyalgia increased from less than 1 per 100 000 to 35 per 100 000. In contrast, there was no consistent change in the incidence of all recorded symptoms of fatigue, with an average of 1503 per 100 000, equivalent to 1.5% per year. CFS/ME and fibromyalgia were rarely diagnosed in children and were uncommon in the elderly. All symptoms and diagnoses were more common in females than in males. The overall incidence of fatigue diagnoses in general has fallen, but the incidence rates of the specific diagnoses of CFS/ME and fibromyalgia have risen, against a background of little change in symptom reporting. This is likely to reflect fashions in diagnostic labelling rather than true changes in incidence.

Comment in: Brain imaging in fatigue syndromes. [J R Soc Med. 2005]

 

Source: Gallagher AM, Thomas JM, Hamilton WT, White PD. Incidence of fatigue symptoms and diagnoses presenting in UK primary care from 1990 to 2001. J R Soc Med. 2004 Dec;97(12):571-5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1079668/ (Full article)

 

What causes chronic fatigue syndrome?

Comment in: Patients with chronic fatigue syndrome are being ignored. [BMJ. 2004]

Comment on: Childhood predictors of self reported chronic fatigue syndrome/myalgic encephalomyelitis in adults: national birth cohort study. [BMJ. 2004]

 

Chronic fatigue syndrome, also known as myalgic encephalomyelitis, is an illness of unknown nature and cause, but most medical authorities now accept its existence.1-3 Research about its cause has been hampered by the absence of a biological marker, the heterogeneous nature of the illness, and difficulties in differentiating cause from effect.2,3 Yet, some progress has been made, particularly when causes are divided into predisposing, triggering, and maintaining factors.

Women get chronic fatigue syndrome more commonly than men for unknown reasons, although increasing evidence suggests a genetic influence on the illness.1,3 Premorbid mood disorders are replicated risk markers for chronic fatigue syndrome;1,3 the risks may be inflated by shared symptoms or they may be markers for those patients with comorbid mood disorders.1,3-5 Another replicated premorbid risk marker is increased consulting of a doctor for minor illnesses up to 15 years before diagnosis,w1 w2 suggesting a general vulnerability for either ill health or seeking health care, the latter possibly being mediated by comorbid anxiety.4

You can read the rest of this comment here: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC524091/

 

Source: White PD. What causes chronic fatigue syndrome? BMJ. 2004 Oct 23;329(7472):928-9. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC524091/ (Full article)

 

The nosology of sub-acute and chronic fatigue syndromes that follow infectious mononucleosis

Abstract:

BACKGROUND: A previous principal components analysis of symptoms occurring after infectious mononucleosis suggested that a discrete fatigue syndrome occurs, which is independent of psychiatric disorder. This work has not been replicated and no latent class analysis of subjects has been published.

METHOD: We prospectively examined a cohort of 150 American primary care patients 2 and 6 months after the onset of corroborated infectious mononucleosis. A subset of 50 subjects was studied 4 years after onset. We performed principal components analyses of both psychological and somatic symptoms and latent class analyses of subjects.

RESULTS: Principal components analyses consistently delineated two fatigue factors at 2 and 6 months and one fatigue factor at 4 years. These factors were separate from a mixed anxiety and depressive factor. A four-class solution for the latent class analyses consisted of most subjects with few symptoms, a few with many symptoms, a group with predominantly mood symptoms and some subjects with fatigue symptoms.

CONCLUSIONS: The symptoms of the principal factors with fatigue were similar to those previously described. Both the factors and classes were independent of an equally delineated mood factor and class. These results support the existence of two discrete chronic fatigue syndromes after infectious mononucleosis, one of which is still demonstrable 4 years after onset.

 

Source: White PD, Thomas JM, Sullivan PF, Buchwald D. The nosology of sub-acute and chronic fatigue syndromes that follow infectious mononucleosis. Psychol Med. 2004 Apr;34(3):499-507. http://www.ncbi.nlm.nih.gov/pubmed/15259835

 

Identification of ambiguities in the 1994 chronic fatigue syndrome research case definition and recommendations for resolution

Abstract:

BACKGROUND: Chronic fatigue syndrome (CFS) is defined by symptoms and disability, has no confirmatory physical signs or characteristic laboratory abnormalities, and the etiology and pathophysiology remain unknown. Difficulties with accurate case ascertainment contribute to this ignorance.

METHODS: Experienced investigators from around the world who are involved in CFS research met for a series of three day workshops in 2000, 2001 and 2002 intended to identify the problems in application of the current CFS case definition. The investigators were divided into focus groups and each group was charged with a topic. The investigators in each focus group relied on their own clinical and scientific knowledge, brainstorming within each group and with all investigators when focus group summaries were presented. Relevant literature was selected and reviewed independent of the workshops. The relevant literature was circulated via list-serves and resolved as being relevant by group consensus. Focus group reports were analyzed and compiled into the recommendations presented here.

RESULTS: Ambiguities in the current CFS research definition that contribute to inconsistent case identification were identified. Recommendations for use of the definition, standardization of classification instruments and study design issues are presented that are intended to improve the precision of case ascertainment. The International CFS Study Group also identified ambiguities associated with exclusionary and comorbid conditions and reviewed the standardized, internationally applicable instruments used to measure symptoms, fatigue intensity and associated disability.

CONCLUSION: This paper provides an approach to guide systematic, and hopefully reproducible, application of the current case definition, so that case ascertainment would be more uniform across sites. Ultimately, an operational CFS case definition will need to be based on empirical studies designed to delineate the possibly distinct biological pathways that result in chronic fatigue.

Comment in: Identification of ambiguities in the 1994 chronic fatigue syndrome research case definition and recommendations for resolution. [BMC Health Serv Res. 2005]

 

Source: Reeves WC, Lloyd A, Vernon SD, Klimas N, Jason LA, Bleijenberg G, Evengard B, White PD, Nisenbaum R, Unger ER; International Chronic Fatigue Syndrome Study Group. Identification of ambiguities in the 1994 chronic fatigue syndrome research case definition and recommendations for resolution. BMC Health Serv Res. 2003 Dec 31;3(1):25. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC317472/ (Full article)

 

Recovery from infectious mononucleosis: a case for more than symptomatic therapy? A systematic review

Abstract:

Infectious mononucleosis is usually an acute, transiently incapacitating condition, but for some sufferers it precipitates chronic illness. It is unclear which patients are at risk of a prolonged state of illness following onset of infectious mononucleosis and if there are any useful preventive measures that would facilitate recovery. The aim of this study was to review all cohort studies and intervention trials that provide information on: (a) the longitudinal course of ill health subsequent to the onset of infectious mononucleosis; (b) the relationship between psychosocial and clinical factors and recovery rate; and (c) the effect of interventions on recovery.

A systematic review was conducted, based on a search of the PSYCHINFO, MEDLINE, EMBASE and CINHAL databases up to October 2001, and ISI Science and Social Sciences Citation Indices up to 22 November 2001. Eight papers were identified that gave data on illness following onset of infectious mononucleosis. The best evidence concluded that there is a distinct fatigue syndrome after infectious mononucleosis. Eight papers explored risk factors for prolonged illness following acute infectious mononucleosis.

Results varied on the association of acute illness characteristics and psychological features with prolonged ill health. Poor physical functioning, namely lengthy convalescence and being less fit or active, consistently predicted chronic ill health. Three trials reported on interventions that aimed to shorten the time taken to resolve symptoms after uncomplicated infectious mononucleosis. None of the drug trials found any evidence that drug therapy shortens recovery time. The trial that compared the effect of activity with imposed bed rest, found that those patients allowed out of bed as soon as they felt able reported a quicker recovery. More information is needed on the course of ill health subsequent to the onset of infectious mononucleosis. Certain risk factors associated with delay may be amenable to a simple intervention in primary care.

 

Source: Candy B, Chalder T, Cleare AJ, Wessely S, White PD, Hotopf M. Recovery from infectious mononucleosis: a case for more than symptomatic therapy? A systematic review. Br J Gen Pract. 2002 Oct;52(483):844-51. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1316091/ (Full article)

 

A comparison of patients with chronic fatigue syndrome attending separate fatigue clinics based in immunology and psychiatry

Abstract:

Hospital clinics for patients with chronic unexplained fatigue are held in departments of various disciplines. This causes difficulties for referrers in choosing the appropriate clinic and for researchers in generalizing findings from one type of clinic to others.

We randomly selected 37 outpatients attending an immunology fatigue clinic and 36 outpatients attending a psychiatry fatigue clinic, all of whom had chronic fatigue syndrome. We compared demographic factors, symptoms, disability, quality of life, psychological distress and illness attributions.

The patients from the two clinics were closely similar in their specific symptoms, disability, quality of life, psychological distress and previous attendance to mental health professionals. Psychological distress was high and equal in the two samples. The proportion of men was greater among patients attending the immunology clinic. In a post-hoc analysis, 64% of immunology attenders attributed their fatigue to physical factors, compared with 31% of psychiatry clinic attenders (chi(2)=6.35, 1 d.f., P=0.01).

These findings suggest that research data from one type of chronic fatigue clinic can be generalized to others. Clinically similar patients are referred to different clinics, and the choice of clinic may be influenced by the patients’ illness beliefs. The high levels of emotional distress suggest that psychosocial management is as important as physical management in hospital outpatients with chronic fatigue syndrome, irrespective of its aetiology.

 

Source: White PD, Pinching AJ, Rakib A, Castle M, Hedge B, Priebe S. A comparison of patients with chronic fatigue syndrome attending separate fatigue clinics based in immunology and psychiatry. J R Soc Med. 2002 Sep;95(9):440-4. http://www.ncbi.nlm.nih.gov/pubmed/12205207