Predictors of outcome in fatigued employees on sick leave: results from a randomised trial

Abstract:

OBJECTIVE: The main objective of this study was to identify predictors of fatigue caseness, work resumption and chronic fatigue syndrome (CFS)-like caseness in a sample of fatigued employees on sick leave.

METHODS: For 12 months, 151 fatigued employees on sick leave, 44% of whom met research criteria for CFS at baseline, were followed. Measures included fatigue, health aspects, psychological problems, burnout, causal attributions and self-efficacy. Logistic regression analysis was used to determine associations between predictor variables at baseline and outcome at follow-up.

RESULTS: After 12 months, 43% of the patients were no longer fatigue cases, and 62% had resumed work. Recovery from fatigue caseness was predicted by stronger psychological attributions and other perception-related factors, whereas work resumption was predicted by lower age, male sex, CFS-like caseness and less cognitive difficulties. Lower physical functioning scores were predictive of (the development of) CFS-like caseness.

CONCLUSION: Recovering from persistent fatigue and work resumption seem to result from different underlying processes and do not necessarily fall together. As many factors associated with outcome in fatigue reflect illness perception, the prevention of persistent fatigue and CFS may partly be achieved by the modification of perception.

 

Source: Huibers MJ, Bleijenberg G, van Amelsvoort LG, Beurskens AJ, van Schayck CP, Bazelmans E, Knottnerus JA. Predictors of outcome in fatigued employees on sick leave: results from a randomised trial. J Psychosom Res. 2004 Nov;57(5):443-9. http://www.ncbi.nlm.nih.gov/pubmed/15581647

 

Sociodemographic and symptom correlates of fatigue in an adolescent primary care sample

Abstract:

PURPOSE: To describe the prevalence of prolonged fatigue, chronic fatigue syndrome (CFS)-like illness, and associated symptom patterns in adolescents attending primary care.

METHODS: The design was cross-sectional. A questionnaire designed by the authors assessing fatigue and associated symptoms was administered to 901 adolescents (aged 11-18 years) attending 12 primary care clinics in the Chicago area. Prevalence rates for prolonged fatigue and CFS-like illness were calculated. Univariate comparisons involving sociodemographic data and fatigue severity were made between adolescents with and without prolonged fatigue, and sociodemographic and symptom predictors of prolonged fatigue were identified using logistic regression analysis.

RESULTS: Prolonged fatigue (> or = 1 month) occurred at a rate of 8.0% and CFS-like illness occurred at a rate of 4.4%. Adolescents with prolonged fatigue were significantly older and also reported greater fatigue severity than those without fatigue. Findings from logistic regression indicated that, in addition to increasing age, headaches, muscle pains, fever, and fatigue made worse by exercise were significantly associated with prolonged fatigue.

CONCLUSIONS: Abnormal fatigue is a disabling and prevalent condition in adolescents in primary care. It is associated with a number of additional symptoms, many of which may have viral origins.

 

Source: Mears CJ, Taylor RR, Jordan KM, Binns HJ; Pediatric Practice Research Group. Sociodemographic and symptom correlates of fatigue in an adolescent primary care sample. J Adolesc Health. 2004 Dec;35(6):528e.21-6. http://www.ncbi.nlm.nih.gov/pubmed/15581533

 

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)

 

Prediction of peak oxygen uptake in patients fulfilling the 1994 CDC criteria for chronic fatigue syndrome

Abstract:

PURPOSE: To establish an inexpensive, simple method of predicting peak oxygen uptake (VO2peak) in patients fulfilling the 1994 Centers for Disease Control and Prevention (CDC) criteria for chronic fatigue syndrome (CFS).

DESIGN: A retrospective observational study.

SETTING: An outpatient tertiary care chronic fatigue clinic.

SUBJECTS: Two hundred and forty consecutive patients fulfilling the 1994 CDC criteria for CFS.

INTERVENTIONS: Heart rate, metabolic and ventilatory parameters were measured continuously during a maximal exercise stress test on a bicycle ergometer. Using the equation peak oxygen uptake = 13.1 x peak workload +284 (used by Mullis et al., Br J Sports Med 1999; 33: 352-56), VO2peak was predicted from the peak workload of a maximal exercise capacity test. Pearson correlation coefficient and linear regression analysis were used to establish the most accurate way to predict VO2peak.

RESULTS: Percentage error encountered when comparing actual measured VO2peak with predicted value was 17.3% (+/-10.0). A strong correlation between VO2peak and peak workload was observed (r= 0.89, p < 0.001). A regression analysis established the relation as VO2peak = 10.47 x peak workload +284.1, where VO2peak is given in ml/min and peak workload in W (error in prediction = 11.0+/-9.5%).

CONCLUSIONS: Monitoring of the peak workload during a maximal, graded bicycle ergometric test suffices to predict the VO2peak. When predicting VO2peak the used operational definition for the diagnosis of CFS could be taken into account. Compared with the equation used by Mullis et al., peak workload is multiplied by 10.47 in order to predict peak oxygen uptake in CDC-defined CFS patients.

 

Source: Nijs J, De Meirleir K. Prediction of peak oxygen uptake in patients fulfilling the 1994 CDC criteria for chronic fatigue syndrome. Clin Rehabil. 2004 Nov;18(7):785-92. http://www.ncbi.nlm.nih.gov/pubmed/15573835

 

Association between chronic fatigue syndrome and the corticosteroid-binding globulin gene ALA SER224 polymorphism

Abstract:

Chronic fatigue syndrome (CFS) is characterized by idiopathic fatigue of greater than 6 months’ duration with postexertional exacerbation and many other symptoms. A trend toward relative hypocortisolism is described in CFS. Twin and family studies indicate a substantial genetic etiologic component to CFS. Recently, severe corticosteroid-binding globulin (CBG) gene mutations have been associated with CFS in isolated kindreds. Human leukocyte elastase, an enzyme important in CBG catabolism at inflammatory sites, is reported to be elevated in CFS. We hypothesized that CBG gene polymorphisms may act as a genetic risk factor for CFS.

A total of 248 patients with CFS defined by Centers for Disease Control criteria, and 248 controls were recruited. Sequencing and restriction enzyme testing of the CBG gene coding region allowed detection of severe CBG gene mutations and a common exon 3 polymorphism (c.825G–>T, Ala-Ser224).

Plasma CBG levels were measured in 125 CFS patients and 198 controls by radioimmunoassay. Total and free (calculated and measured) cortisol levels were ascertained in single samples between 8-10 a.m. The age of onset (mid 30s) and gender ratio (2.2:1, female:male) of the patients were similar to those reported in U.S. epidemiologic studies.

A trend toward a preponderance of serine224 homozygosity among the CFS patients was noted, compared with controls (chi2 = 5.31, P = 0.07). Immunoreactive-CBG (IR-CBG) levels were higher in Serine/Alanine (Ser/Ala) than Ala/Ala subjects and higher again in Ser/Ser subjects, this effect was strongest in controls; Ser/Ser: 46.1+/-1.8 (n = 31, P = 0.03) vs. Ser/Ala: 42.4+/-1.0 (n = 56, P = 0.05) vs. Ala/Ala: 40.8+/-1.7 microg/mL (n = 21). Despite higher CBG levels, there was a nonsignificant trend toward lower total and free plasma cortisol in serine allele positive patients, total cortisol: Ser/Ser: 13.3+/-1.4 (n = 34) vs. Ser/Ala: 14.0+/-0.7 (n = 66) vs. Ala/Ala: 15.4+/-1.0 (n = 23).

Homozygosity for the serine allele of the CBG gene may predispose to CFS, perhaps due to an effect on hypothalamic-pituitary-adrenal axis function related to altered CBG-cortisol transport function or immune-cortisol interactions.

 

Source: Torpy DJ, Bachmann AW, Gartside M, Grice JE, Harris JM, Clifton P, Easteal S, Jackson RV, Whitworth JA. Association between chronic fatigue syndrome and the corticosteroid-binding globulin gene ALA SER224 polymorphism. Endocr Res. 2004 Aug;30(3):417-29. http://www.ncbi.nlm.nih.gov/pubmed/15554358

 

Exhaustion–not fatigue

Erlend Hem & Jon Håvard Loge refutes the language gap in this Journal no. 18/2004 our argument that “chronic  exhaustion syndrome” should be the Norwegian term for “chronic fatigue syndrome” ( 1 , 2 ). In his speech, they write that “many patients with somatic diseases and fatigue would probably feel somewhat alien to mention symptom as fatigue, because fatigue usually linked to a prior activity” ( 2 ).

You can read the rest of this comment here: http://tidsskriftet.no/article/1095666

 

Source: Wyller VB, Wyller TB. Exhaustion–not fatigue. Tidsskr Nor Laegeforen. 2004 Nov 4;124(21):2802; author reply 2802. [Article in Norwegian] http://tidsskriftet.no/article/1095666 (Full article)

 

Factors influencing the diagnosis of chronic fatigue syndrome

Abstract:

BACKGROUND: Most of what is believed about chronic fatigue syndrome (CFS) is based on clinic-based studies. These studies may not reflect CFS cases in the population.

METHODS: We used data from a population-based study of CFS to identify factors associated with receiving a CFS diagnosis. Wichita, Kan, residents were screened by random-digit dialing. Eligible individuals completed a telephone interview. Respondents meeting CFS criteria were invited for a clinical evaluation to confirm CFS. We analyzed all persons with confirmed CFS. The main outcomes of this study, prevalence and incidence of CFS, are published elsewhere. Herein, we present an exploratory analysis with previous CFS diagnosis as the outcome, predicted by demographic and symptom characteristics.

RESULTS: We confirmed CFS in 90 subjects; 14 (16%) had been previously diagnosed as having CFS. Persons in the middle- vs the higher-income group were more likely to have been diagnosed as having CFS (9 [29%] of 31 subjects vs 3 [8%] of 39 subjects; P = .03), as were those with sudden vs gradual fatigue onset (7 [41%] of 17 subjects vs 4 [6%] of 64 subjects; P < .01), those reporting tender lymph nodes (7 [33%] of 21 subjects vs 7 [10%] of 69 subjects; P = .02), and those reporting a sore throat (6 [35%] of 17 subjects vs 8 [11%] of 73 subjects; P = .02). Only 17 (21%) of 81 subjects had sudden fatigue onset, and tender lymph nodes (reported in 21 [23%] of 90 subjects) and a sore throat (reported in 17 [19%] of 90 subjects) were the least common symptoms.

CONCLUSION: Most cases of CFS in the population are unrecognized by the medical community; persons diagnosed as having CFS may be different from persons with CFS in the general population.

 

Source: Solomon L, Reeves WC. Factors influencing the diagnosis of chronic fatigue syndrome. Arch Intern Med. 2004 Nov 8;164(20):2241-5. http://www.ncbi.nlm.nih.gov/pubmed/15534161

 

Perceived stigma in functional somatic syndromes and comparable medical conditions

Abstract:

OBJECTIVE: To determine if patients with functional somatic syndromes (FSS) perceive greater levels of stigma than patients with comparable medical conditions that have a clear medical pathology.

METHODS: Patients with chronic fatigue syndrome (CFS), fibromyalgia (FM), or irritable bowel syndrome (IBS) were compared to multiple sclerosis (MS), rheumatoid arthritis (RA), and inflammatory bowel disease (IBS), respectively.

RESULTS: There were greater levels of perceived stigma in the combined group of FSS compared to the medical control group. When each FSS was compared to its matched control group, only CFS had a higher level of perceived stigma. These results remained when controlling for other variables relevant to stigma.

CONCLUSIONS: The higher level of perceived stigma in CFS may be due to the ambiguity of its status as a medical condition. The absence of this effect in FM and IBS is consistent with a greater level of acceptance of these disorders as medical illnesses.

 

Source: Looper K, Kirmayer LJ. Perceived stigma in functional somatic syndromes and comparable medical conditions. J Psychosom Res. 2004 Oct;57(4):373-8. http://www.ncbi.nlm.nih.gov/pubmed/15518673

 

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)

 

Differential-display PCR of peripheral blood for biomarker discovery in chronic fatigue syndrome

Abstract:

We used differential-display PCR of peripheral blood mononuclear cells (PBMCs) to search for candidate biomarkers for chronic fatigue syndrome(CFS). PBMCs were collected from a subject with CFS and an age- and sex-matched control before and 24 h after exercise. RNA expression profiles were generated using 46 primer combinations, and the similarity between the individuals was striking.

Differentially expressed bands were excised, reamplified, and sequenced, yielding 95 nonredundant sequences, of which 50 matched to known gene transcripts, 38 matched to genes with unknown functions, and 7 had no similarity to any database entry. Most (86%) of the differences between the two subjects were present at baseline.

Differential expression of ten genes was verified by real-time reverse-transcription PCR: five (cystatin F, MHC class II, platelet factor 4, fetal brain expressed sequence tag, and perforin) were downregulated, and the remaining five genes (cathepsin B, DNA polymerase epsilon4, novel EST PBMC191MSt, heparanase precursor, and ORF2/L1 element) were upregulated in the subject with CFS. Many of these genes have known functions in defense and immunity, thus supporting prior suggestions of immune dysregulation in the pathogenesis of CFS.

Differential-display PCR is a powerful tool for identification of candidate biomarkers. Investigation of these markers in samples from well-designed epidemiological studies of CFS will be required to determine the validity of these candidate biomarkers. The real-time reverse-transcription PCR assays that we developed for assay of these biomarkers will facilitate high-throughput testing of these additional samples.

 

Source: Steinau M, Unger ER, Vernon SD, Jones JF, Rajeevan MS. Differential-display PCR of peripheral blood for biomarker discovery in chronic fatigue syndrome. J Mol Med (Berl). 2004 Nov;82(11):750-5. Epub 2004 Oct 14. http://www.ncbi.nlm.nih.gov/pubmed/15490094