Category: Case Definition

Chronic fatigue syndrome: a clinical and laboratory study with a well matched control group

Abstract:

OBJECTIVE: To investigate the relation between severity of complaints, laboratory data and psychological parameters in patients with chronic fatigue syndrome (CFS).

SUBJECTS: Eighty-eight patients with CFS and 77 healthy controls matched for age, sex and geographical area.

METHODS: Patients and controls visited our outpatient clinic for a detailed medical history, physical examination and psychological tests: Checklist Individual Strength (CIS). Beck Depression Inventory (BDI) and Sickness Impact Profile (SIP). Venous blood was drawn for a complete blood cell count, serum chemistry panel, C-reactive protein and serological tests on a panel of infectious agents.

RESULTS: All patients fulfilled the criteria for CFS as described by Sharpe et al. (J R Soc Med 1991; 84: 118-21), only 18 patients (20.5%) fulfilled the CDC criteria. The outcome of serum chemistry tests and haematological tests were within the normal range. No significant differences were found in the outcome of serological tests. Compared to controls, significant differences were found in the results on the CIS, the BDI, and the SIP. These results varied with the number of complaints (CDC criteria). When the number of complaints was included as the covariate in the analysis, there were no significant differences on fatigue severity, depression, and functional impairment between patients who fulfilled the CDC criteria and patients who did not.

CONCLUSION: It is concluded that the psychological parameters of fatigue severity, depression and functional impairment are related to the clinical severity of the illness. Because the extensive panel of laboratory tests applied in this study did not discriminate between patients and controls, it was not possible to investigate a possible relation between the outcomes of psychological and laboratory testing.

Comment in: Chronic fatigue syndrome: a clinical and laboratory study with a well-matched control group. [J Intern Med. 2004]

 

Source: Swanink CM, Vercoulen JH, Bleijenberg G, Fennis JF, Galama JM, van der Meer JW. Chronic fatigue syndrome: a clinical and laboratory study with a well matched control group. J Intern Med. 1995 May;237(5):499-506. http://www.ncbi.nlm.nih.gov/pubmed/7738491

 

Chronic fatigue syndrome and myalgic encephalomyelitis

Comment on:

Chronic fatigue syndrome. Distinguish between syndromes… [BMJ. 1994]

Chronic fatigue syndrome. Role of psychological factors overemphasised. [BMJ. 1994]

 

Editor,-Our recent editorial on the chronic fatigue syndrome and myalgic encephalomyelitis prompted considerable correspondence,’ which raised issues of case definition, clinical management, and attitudes towards people with psychiatric illnesses. Sadly, many of our critics show that the editor of the BMJ is wrong to state in the “editor’s choice” in the issue of 14 May that “only the naivest medical students think that diseases have some independent, objective reality.” Medical students show greater intellectual sophistication in tackling the classification of ill defined illnesses than many patients and doctors-and particularly medical practitioners with self diagnosed myalgic encephalomyelitis.

Case definition-Ellen M Goudsmit’ and Nick Anderson’ assert that research criteria for the chronic fatigue syndrome fail to distinguish myalgic encephalomyelitis and exaggerate psychiatric associations. The best replicated research finding, however, is that patients suffer substantial emotional morbidity, whether the chronic fatigue syndrome is defined by British or, as patient groups prefer, Australian or American criteria. All three sets of criteria can be used to identify cases on a continuum of fatigue, which includes myalgic encephalomyelitis. We did not cite DO Ho-Yen’s prevalence study as it used an idiosyncratic definition of cases of the ‘chronic fatigue syndrome and surveyed doctors’ diagnoses rather than patients.

You can read the full comment here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2540769/pdf/bmj00450-0067b.pdf

 

Source: Lawrie SM, Pelosi AJ. Chronic fatigue syndrome and myalgic encephalomyelitis. BMJ. 1994 Jul 23;309(6949):275. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2540769/

 

Chronic fatigue syndrome: point and counterpoint

Abstract:

Two clinical investigators with divergent views on chronic fatigue syndrome (CFS) were invited to debate their positions at the 1993 annual meeting of The Infectious Disease Society of America. Major points of the discourse focused on the value of the US Centers for Disease Control and Prevention case definition of CFS, the potential roles of infectious and allergic problems in the syndrome, the confounding problem of concurrent psychiatric problems, and the utility of diagnostic tests.

 

Source: Straus SE, Komaroff AL, Wedner HJ. Chronic fatigue syndrome: point and counterpoint. J Infect Dis. 1994 Jul;170(1):1-6. http://www.ncbi.nlm.nih.gov/pubmed/8014482

 

Chronic fatigue syndrome. …and study them separately

Comment on: Chronic fatigue syndrome: prevalence and outcome. [BMJ. 1994]

 

Editor,-The struggle over myalgic encephalomyelitis and the chronic fatigue syndrome is not, as S M Lawrie and A J Pelosi suggest, whether they are physical or mental illnesses. Both sides in this debate accept that most illnesses combine organic and psychological factors. The struggle is about methodology and definition and, in particular, how different methodologies and definitions inevitably lead to different findings on the degree to which depression is a perpetuating agent in these conditions.

One side favours studying the chronic fatigue syndrome as a single entity, arguing that there is insufficient knowledge at present to differentiate between different chronic fatigue syndromes. This side prefers Sharpe et al’s broad definition of the syndrome, which includes depressive illness, anxiety disorders, and the hyperventilation syndrome.2 Unsurprisingly, studies that use these criteria find higher levels of depression ) or “psychosocial disorders”-yet another woolly term).

The other side argues that there is sufficient knowledge to distinguish specific chronic fatigue syndromes, particularly the much studied myalgic encephalomyelitis, and that it must be better science in these cases to study such syndromes in their own right. Furthermore, it argues that the study groups used in research based on broadbrush criteria will have been so aetiologically heterogeneous as to invalidate the findings. This side, which includes the national patient organisations, equates myalgic encephalomyelitis with Holmes et als tighter definition of the chronic fatigue syndrome, which focuses more on organic symptoms and, again unsurprisingly, finds lower levels of depression similar to those found in patients with cancer and multiple sclerosis-that is, the levels that might be predicted in any chronic illness.3

You can read the rest of this comment here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2540172/pdf/bmj00440-0054a.pdf

 

Source: Anderson N. Chronic fatigue syndrome. …and study them separately. BMJ. 1994 May 14;308(6939):1298. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2540172/

 

Chronic fatigue syndrome. Distinguish between syndromes…

Comment in: Chronic fatigue syndrome and myalgic encephalomyelitis. [BMJ. 1994]

Comment on: Longitudinal study of outcome of chronic fatigue syndrome. [BMJ. 1994]

 

EDITOR,-I note that several people writing in the BMY are still confusing myalgic encephalomyelitis with the chronic fatigue syndrome. I wish to clarify matters. From a scientist’s point of view, the main problem is not the term chronic fatigue syndrome but the various diagnostic criteria that go with it. For instance, the strict Australian definition adopted by Wilson et al is similar to that for myalgic encephalomyelitis.2 As a result, it is reasonably certain that in this article the two names probably refer to the same disease.

The “Oxford” criteria used in Britain, however, are far broader, covering all patients whose severe, unexplained fatigue has been present for at least half of the time and for at least six months. The only other requirements are that the fatigue must have had a definite onset and that it affects both physical and mental functioning. Unlike with the strict Australian definition, no immunological criteria have to be met.2 Moreover, there do not have to be appreciable fluctuations in symptoms still a major criterion for myalgic encephalomyelitis.

In terms of prevalence, a recent study found that 17 of 686 (2-5%) attenders in general practice fulfilled the Oxford criteria for the chronic fatigue syndrome.3 When a further four patients who did not meet the criterion of a definite onset were also included the estimated prevalence increased to 3%. In contrast, the prevalence of myalgic encephalomyelitis rarely exceeds 1-5 per 1000.4

Most patients who fulfil the Oxford criteria suffer not from myalgic encephalomyelitis but from more common conditions, notably depression, anxiety states, sleep disorders, and fibromyalgia. None of these disorders occur in epidemics …

You can read the rest of this comment here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2540201/pdf/bmj00440-0053c.pdf

 

Source: Goudsmit EM. Chronic fatigue syndrome. Distinguish between syndromes… BMJ. 1994 May 14;308(6939):1297-8. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2540201/

 

A comparison of case definitions of chronic fatigue syndrome

Abstract:

We compared three case definitions of chronic fatigue syndrome (CFS) applied to patients followed in CFS clinics at two institutions. All patients had debilitating fatigue without apparent etiology; patients with medical conditions associated with chronic fatigue and with major psychiatric disorders were stratified and presented separately. Patients were classified according to whether they met case definitions developed by a Centers for Disease Control and Prevention (CDC) Working Group, a British group, or an Australian group. When findings for 805 patients followed at the two clinics were combined, 61% met the CDC criteria, 55% met the British criteria, and 56% met the Australian criteria; these proportions were relatively similar at both sites. In addition, similar laboratory abnormalities were found for all case groups and for fatigued patients who met none of the three case definitions. These data suggest that more inclusive case definitions may be superior.

 

Source: Bates DW, Buchwald D, Lee J, Kith P, Doolittle TH, Umali P, Komaroff AL. A comparison of case definitions of chronic fatigue syndrome. Clin Infect Dis. 1994 Jan;18 Suppl 1:S11-5. http://www.ncbi.nlm.nih.gov/pubmed/8148436

 

Prevalence of fatigue and chronic fatigue syndrome in a primary care practice

Abstract:

BACKGROUND: Our goals were to determine the prevalence of unusual, debilitating fatigue and the frequency with which it was associated with the chronic fatigue syndrome (CFS) or other physical or psychological illness in an outpatient clinic population.

METHODS: We prospectively evaluated a cohort of 1000 consecutive patients in a primary care clinic in an urban, hospital-based general medicine practice. The study protocol included a detailed history, physical examination, and laboratory and psychiatric testing.

RESULTS: Five patients who came because of CFS studies were excluded. Of the remaining 995, 323 reported fatigue, and 271 (27%) complained of at least 6 months of unusual fatigue that interfered with their daily lives. Of the 271, self-report or record review revealed a medical or psychiatric condition that could have explained the fatigue in 186 (69%). Thus, 85 (8.5%) of 995 patients had a debilitating fatigue of at least 6 months’ duration, without apparent cause. Of these patients, 48 refused further evaluation, and 11 were unavailable for follow-up; 26 completed the protocol. Three of the 26 were hypothyroid, and one had a major psychiatric disorder. Of the remaining 22 patients, three met Centers for Disease Control and Prevention criteria for CFS, four met British criteria, and 10 met the Australian case definition. The point prevalences of CFS were thus 0.3% (95% confidence interval [CI], 0% to 0.6%), 0.4% (95% CI, 0% to 0.8%), and 1.0% (95% CI, 0.4% to 1.6%) using the Centers for Disease Control and Prevention, British, and Australian case definitions, respectively. These estimates were conservative, because they assumed that none of the patients who refused evaluation or were unavailable for follow-up would meet criteria for CFS.

CONCLUSIONS: While chronic, debilitating fatigue is common in medical outpatients, CFS is relatively uncommon. Prevalence depends substantially on the case definition used.

 

Source: Bates DW, Schmitt W, Buchwald D, Ware NC, Lee J, Thoyer E, Kornish RJ, Komaroff AL. Prevalence of fatigue and chronic fatigue syndrome in a primary care practice. Arch Intern Med. 1993 Dec 27;153(24):2759-65. http://www.ncbi.nlm.nih.gov/pubmed/8257251

 

The chronic fatigue syndrome

Sir, Although many doctors equate chronic fatigue syndrome (Oxford definition) with what we call myalgic encephalomyelitis (ME), there are some noteworthy differences.

Firstly, in Britain, chronic fatigue syndrome is an umbrella term covering a number of different conditions including neurasthenia, effort syndrome and fibromyalgia. ME is a more specific entity (see the ‘ 10, 1992) and unlike the above, has been closely linked to a persistent infection and immune system activation.

Secondly, while profound fatigue is undeniably the most common symptom of ME, it is rather different from the type of tiredness which people normally experience after exertion. For example, it is often accompanied by feelings of illness which are so unlike anything which people have had before that patients frequently say they cannot describe it. Some have referred to the latter as a severe ‘flu-like’ malaise, others have likened it to being poisoned. Regrettably, having subsumed ME under a general heading of chronic fatigue syndrome, this important and disabling aspect of ME will almost certainly be overlooked.

You can read the rest of this letter here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2399627/pdf/postmedj00050-0083a.pdf

 

Source: Macintyre A, Hume MC. The chronic fatigue syndrome. Postgrad Med J. 1993 Feb;69(808):164. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2399627/

 

Diagnostic criteria for chronic fatigue syndrome by the CFS Study Group in Japan

Abstract:

Much interest recently has been given to chronic fatigue syndrome (CFS) in Japan as other countries. The CFS Study Group sponsored by the Ministry of Health and Welfare has been developed since April 1991, A diagnostic criteria for CFS was newly proposed by this group. The criteria is substantially based upon the working case definition, which was made by Holmes and colleagues in 1988. There are some modification from CDC working case definition; the criteria of probable cases of CFS was defined, and postinfectious CFS was also given.

 

Source: Kitani T, Kuratsune H, Yamaguchi K. Diagnostic criteria for chronic fatigue syndrome by the CFS Study Group in Japan. Nihon Rinsho. 1992 Nov;50(11):2600-5. [Article in Japanese] http://www.ncbi.nlm.nih.gov/pubmed/1287236

 

Definition of the chronic fatigue syndrome and its issues

Abstract:

This article reviewed Definition of CFS proposed by CDC 1988. There are several issues in Definition for CFS of CDC. It is presented that other chronic clinical conditions have been satisfactorily excluded, including preexisting psychiatric diseases in (2) of major criteria.

However, fibromyalgia can not be excluded from the fifth symptom of minor criteria, myalgia, and also depression from the ninth symptom.

It is practically difficult to define impairment of average daily activity below 50% of the patient’s premorbid activity level for a period of at least 6 months, as shown in (1) of major criteria, and it is not adapted for a first visit patient.

Definition for CFS of CDC has been discussed on EBV infection, but not written on postviral fatigue syndrome and myalgic encephalomyelitis. Especially whether epidemic type of CFS is present or not was not discussed. Diagnostic criteria of CFS is necessary for clinical practice.

 

Source: Hashimoto N. Definition of the chronic fatigue syndrome and its issues. Nihon Rinsho. 1992 Nov;50(11):2591-9. [Article in Japanese] http://www.ncbi.nlm.nih.gov/pubmed/1287235