Family Practice Vol. 16, No. 6, 602-604
© Oxford University Press 1999
Chronic Fatigue Syndrome and Primary Fibromyalgia Syndrome as recognized by GPs
University Hospital Nijmegen, Department of Medical Psychology, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands,
a Department of Medical Microbiology,
b Department of General Internal Medicine and
c Department of Family Medicine, Social Medicine and Nursing Home Medicine, The Netherlands.
Bazelmans E, Vercoulen JHMM, Swanink CMA, Fennis JFM, Galama JMD, van Weel C, van der Meer JWM and Bleijenberg G. Chronic Fatigue Syndrome and Primary Fibromyalgia Syndrome as recognized by GPs. Family Practice 1999; 16: 602–604. A modified version of this article has been published in Dutch, in Ned Tijdschr Geneeskd, 1997; 31: 1520–1523.
Received 5 February 1999; Revised 21 June 1999; Accepted 25 June 1999.
Abstract
Background. Prevalence studies on Chronic Fatigue Syndrome (CFS) are rare. Because of the similarity in symptoms, the prevalence of Primary Fibromyalgia Syndrome (PFS) was investigated at the same time.
Objectives. To determine the prevalence of CFS and PFS as recognized by GPs in The Netherlands and to inform them of the existence of CFS.
Methods. A postal questionnaire was sent to all GPs.
Results. The questionnaire was returned by 60% of the GPs. Seventy-three per cent reported one or more CFS patients and 83% one or more PFS patients in their practice.
Conclusion. The estimated prevalence of CFS as recognized by GPs of 112 (PFS 157) patients per 100,000 is a minimum estimate.
Keywords. Chronic Fatigue Syndrome, GPs, Primary Fibromyalgia Syndrome.
Introduction
Chronic Fatigue Syndrome (CFS) is described as severe fatigue which has persisted for more than 6 months, is not relieved by bedrest and leads to severe disability in daily life. A physical explanation for this condition has not yet been found. Various other complaints can accompany the fatigue, such as muscular pain, headache, memory and concentration problems, and depression. Despite extensive research, the cause of CFS is still unknown and the diagnosis is established by means of exclusion. For this reason, some physicians do not accept CFS as a disease. However, CFS has since been recognized as a disease by the World Health Organisation and has been included in the International Classification of Diseases (ICD 10).
Many of the symptoms of CFS are also characteristic of the Primary Fibromyalgia Syndrome (PFS). To prevent confusion, one has to inquire for both syndromes. In this article, the results of a study carried out among Dutch GPs are described. There were two major aims. The first was to gain insight into the number of CFS and PFS cases as recognized by GPs in The Netherlands. The second aim was to confront all GPs in The Netherlands with the existence of CFS and to give them information about this disease.
Method
All 6657 GPs in The Netherlands received a mailed questionnaire. A Dutch institute for health research (NIVEL) provided their names and addresses. In the questionnaire the GPs were asked to report the size of their practice, the number of CFS and PFS patients in their practice and the distribution of these patients according to age and sex. A text with a definition of CFS and PFS was included in the questionnaire. For CFS a complaint duration of 1 year was used. If a response was not received within 6 weeks, a reminder was sent.
Results
Response
In total, 4027 questionnaires were returned (60.5%). Of the 4027 questionnaires 3881 (58.3%) were suitable for analysis. A reason for not completing or not filling in the questionnaire was given by 397 of these 3881 GPs. Twenty-seven of the responders (0.7%) said they "never make this diagnosis, find the diagnosis too difficult, or find the diagnosis insufficient", and 37 GPs (1.0%) said they "refuse to make this diagnosis or do not believe in this disease". Other reasons given for not completing the questionnaire were "I do not have my own patient database", "this is not a scientific study", "I do not participate in surveys", "I do not yet have insight", or "I will not review my patient data for this purpose".
Number of CFS and PFS patients as recognized by GPs
The frequency distribution of CFS and PFS patients in their practice, as reported by GPs, is shown in Figure 1
. Seventy-three per cent of the GPs stated that they had one or more CFS patients in their practice. Eighty-three per cent of the GPs reported that they had one or more PFS patients in their practice.
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Since the size of the average practice, as indicated by the GPs, was 2486 patients, the number of CFS patients as recognized by GPs in The Netherlands is 112 per 100 000 inhabitants; for PFS, it is 157 per 100 000 inhabitants. Overall, 81% of the CFS patients and 87% of the PFS patients were female. Among CFS patients, 55% were between 25 and 44 years old versus 48% of the PFS patients.
Discussion
In this survey, GPs reported to recognize 112 CFS patients and 157 PFS patients per 100 000 inhabitants. This means that there are at least 17 000 CFS patients and 24 000 PFS patients in The Netherlands, in a total population of about 15 million inhabitants. The data obtained from this study were validated by comparing the age and sex of the CFS patients of this survey with those of a population of 298 CFS patients who were previously studied in detail by our research group.1 In that cohort, 75% were female and 62% were between 25 and 44 years of age. The respective values for this study are 81% and 55%.
The prevalence rate based on recognitions by GPs in our study is considerably lower than those found in population-based studies, in which prevalence rates of up to 0.56 and 2.6%, respectively, were found.2,3 Such differences may be due to a number of causes. Although a response rate of 60% can be considered high, the question is whether it can be considered representative for all GPs and whether the data can be generalized. It is likely that there were more GPs that did not accept this condition among the 40% non-responders than among the 60% responders. However, if a GP never establishes the diagnosis CFS, this does not mean that there are no patients with CFS in his practice. In addition, the GPs who did fill in the questionnaire may have been conservative in making the diagnosis. The fact that CFS was relatively unknown among GPs also played a role. It is quite likely that only those patients with an obvious diagnosis were included in this survey. If such a survey were to be repeated in the future, then one might expect that a higher number of CFS patients will be recognized by GPs because the presentation of information leads to better recognition. Furthermore, in the present study a fairly conservative definition of CFS was used as far as the duration of the complaints: a fatigue persisting for at least 1 year. This was applied because we had the impression that a number of patients recover within 6 months to a year. If the label CFS is attached to these complaints at an early stage, this may have the effect of perpetuating the complaints. However, in the current agreement on the CDC criteria, in which our group also participated, duration of the complaints is 6 months. This is another reason why the number of CFS patients found in our study will be a low estimate of the number of CFS patients in The Netherlands.
If we take into consideration the fact that 1% of the GPs refuse to establish this diagnosis or do not believe in the disease and that 0.7% do not make the diagnosis or find the condition too difficult to diagnose, then acceptance of the diagnosis CFS is not as poor as is so often suggested. This was also concluded by Denz and Murdoch, who found that the clinical validity of chronic fatigue syndrome was accepted by 90% of the GPs in Otago, New Zealand.4 Fitzgibbon et al. found that CFS as a distinct clinical entity was accepted by 58% of the GPs in Ireland, and that 82% would consider a diagnosis of CFS in their own patients with chronic debilitating fatigue.5 In view of the 60% response rate and the generally positive reactions in our study, it can be said that the aim of confronting and informing all Dutch GPs about the existence of CFS was achieved. Nevertheless, there are still more GPs that diagnose PFS (83%) than diagnose CFS (73%). It is of interest that 27% of the GPs who do not diagnose CFS 65% still diagnose PFS. Of the 17% of the GPs that do report not to have PFS patients in their practice, only 46% diagnose CFS. Because CFS and PFS are rather similar diagnoses, this may indicate that PFS is more accepted than CFS.
Acknowledgments
The study was supported by grants from the ME foundation, the VSB Foundation and the National Foundation for Chronic Diseases.
References
1 Vercoulen JHMM, Swanink CMA, Galama JMD, Fennis JFM, Meer JWM van der, Bleijenberg G. Dimensional assessment of chronic fatigue syndrome. J Psychosom Res 1994; 38: 383–392.[Web of Science][Medline]
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Wessely S, Chalder T, Hirsch S, Wallace P, Wright D. The prevalence and morbidity of chronic fatigue and chronic fatigue syndrome: a prospective primary care study. Am J Pub Health 1997; 87: 1449–1455.
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Lawrie SM, Pelosi AJ. Chronic fatigue syndrome in the community. Prevalence and associations. Br J Psychiatry 1995; 166: 793–797.
4 Denz-Penhey H, Murdoch JC. General practitioners acceptance of the validity of chronic fatigue syndrome as a diagnosis. N Z Med J 1993; 106: 122–124.[Medline]
5 Fitzgibbon EJ, Murphy D, O'Shea K, Kelleher C. Chronic debilitating fatigue in Irish general practice: a survey of general practitioners' experience. Br J Gen Pract 1997; 47: 618–622.[Web of Science][Medline]
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