Family Practice Vol. 16, No. 2, 112-116
© Oxford University Press 1999
How often is the diagnosis bronchial asthma correct?
Unit for Research and Development in Primary Health Care and Department of Primary Health Care, Göteborg University, Gothenburg,
a Asthma and Allergy Centre, Sahlgrenska University Hospital of Gothenburg, Sweden and
b Department of Primary Health Care, Göteborg University, Gothenburg, Sweden.
Dr Bertil Marklund, Unit for Research and Development, Primary Health Care, Halland, Box 113, S-311 22 Falkenberg, Sweden.
Marklund B, Tunsäter A and Bengtsson C. How often is the diagnosis bronchial asthma correct? Family Practice 1999; 16: 112–116.
Received 9 February 1998; Revised 9 September 1998; Accepted 19 November 1998.
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Abstract |
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Background. There are studies indicating that bronchial asthma is often underdiagnosed, while only a little research has been conducted as concerns overdiagnosing asthma.
Objective. We aimed to estimate the number of patients who have been given the wrong diagnosis of asthma.
Methods. All patients aged above 18 years who had visited two GPs during 1994 or 1995, with the diagnosis of bronchial asthma confirmed in the medical register, were examined by a specialist in allergies.
Results. One hundred and twenty-three patients fulfilled the criteria for being included in the study. Eighty-six patients (70%) attended the examination. Of these, 51 (59%) had bronchial asthma, six (7%) asthma in combination with chronic obstructive pulmonary disease (COPD) and 29 (34%) no asthmatic disease.
Conclusion. The study indicates that more accuracy is needed when diagnosing bronchial asthma.
Keywords. Bronchial asthma, diagnosis, primary health care..
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Introduction |
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The annual incidence of bronchial asthma starting in adulthood in the Swedish population varies between 0.1 and 0.5% depending on the definition used.1 In the city of Gothenburg, Sweden, the prevalence of asthma in 1994 was 5.5% in a population of about 450 000.2
Diagnosis of bronchial asthma is not always easy. Studies have shown underdiagnosed asthma in children,3 adolescents4 and adults,5 but little research has been done as concerns overdiagnosing asthma, in spite of the fact that symptoms similar to asthma can be seen in connection with other lung diseases such as chronic obstructive pulmonary disease (COPD), emphysema and chronic bronchitis. The same symptoms can also be seen in patients with cardiac failure, a pulmonary tumour or a hyperventilation syndrome. One group of patients with asthma-like symptoms, not mentioned above, has lately been focused upon. The disease has been called ‘functional breathing disorder' (FBD).6,7 These patients have dyspnoea without any obstruction in their airways. Careful examinations can exclude other heart or lung diseases.
As a consequence of the difficulties in diagnosing asthma, there is an obvious risk of arriving at a wrong diagnosis. The purpose of this study was to estimate the number of these patients.
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Material and methods |
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Selection of subjects
Göteborg is the second town of Sweden, situated on the west coast, comprising about 450 000 inhabitants. In primary health care about 150 GPs are working at approximately 50 primary health care units or at private practices. In order to be able to study a selected group of adult patients (>18 years of age) with the diagnosis of bronchial asthma, two receptions with computerized registers were chosen, where the computer system allowed a search for diagnosis and therapy. One of the primary health care units was a community reception unit with four GPs, and the other one a private reception with two GPs. One physician at each of the units, together with a specialist in allergic diseases, went through all his/her patients with the diagnosis of bronchial asthma. The two GPs had 5 and 10 years of clinical experience, respectively.
At some of the consultations the main reason for the consultation concerned diagnosis other than asthma, but the patient took the opportunity to renew the prescription of drugs for their asthma. Therefore we also searched for patients with no diagnosis of bronchial asthma as a heading in the records, but for whom drugs for asthma had been prescribed, and for whom the diagnosis of bronchial asthma was confirmed in the text of the records. Hence, all patients aged above 18 years who had visited these two GPs during 1994 or 1995 with the diagnosis bronchial asthma and/or using asthma-drugs were included.
Procedure
During the period 14 November 1994 to 24 February 1995, all selected patients were sent a letter inviting them to a free-of-charge, comprehensive investigation for their bronchial asthma. They were told to contact their primary health care centre in order to arrange an appointment for an examination. An overview of the examination of these patients is shown in Figure 1
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Visit 1. . The patient met a nurse educated in allergies, who followed the following procedure:
- A history was taken according to a standardized form. In addition, questions were asked about asthmatic symptoms and smoking habits.
In cases of a positive history of allergy, a skin-prick test was performed.
A ventilatory lung-function test using spirometry was made, measuring FEV1, % of predicted FEV1 and reversibility following administration of ß2-agonists. The patients were asked to stop using bronchodilators 24 hours before spirometry.
Instructions were given for peak expiratory flow (PEF) registration at home for 2 weeks, once in the morning and once in the evening, before and after ß2-agonists. A special form was used.
Visit 2. . The patient met a physician and a nurse, and the procedure was as follows:
- The PEF scores were measured.
Physical examination, including lung and heart auscultation, was performed.
The history taken at the first visit by the nurse was expanded by the doctor.
Evaluation of the diagnosis of each patient
All patients were discussed on a special meeting between the GP, the nurse and a specialist in allergic diseases at a university hospital. If the diagnosis was still considered uncertain, the examination continued in the following way: a pathological FEV1 without reversibility was completed with a cortisone test: 30 mg prednisolone daily for 2 weeks, followed by another spirometry examination. If all reversibility tests were normal and the history still uncertain, a metacholine test was added. In case of a history of exercised-induced symptoms, an exercise test was performed. During this procedure continuous registrations of ventilatory lung function were made as well as measurements of CO2 in order to show potential hyperventilation.
In this study we use an operational approach when defining bronchial asthma; see Table 1. At least one of the following criteria had to be fulfilled:
- a typical history of asthma;
increase of FEV1 >15% from the initial value after administration of a ß2-agonist;
at least three amplitude differences in PEF variations of at least 20% during 2 weeks of registration; these differences may apply both to reversibility and to variability;
increase of FEV1 >15% from the initial value after 2 weeks of treatment with oral steroids;
PC20 < 4 mg/ml at a metacholine challenge test.
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Our definition of FBD (Functional Breathing Disorder) is consistent with the description of Ringsberg et al. 1997.6,7
A condition characterized by ‘various respiratory complaints suggestive of asthma, such as heavy breathing; dyspnoea at rest, during or after exercise; coughing; sputum production; and hyperreactive airways with breathing problems often provoked by physical exercise or chemical irritants. There should be no report of wheezing.' Nor should they have ‘any other diagnosed disease that could affect the respiratory function or any other vital function'.
Negative asthma tests are required:
- "Lack of reversibility, defined as an increase of FEV1 or PEFR values after inhalation of a ß2-stimulant < 10%.
- Normal FEV1 or PEFR values before inhalation of a ß2-stimulant defined as >95% of predicted normal.
- A negative methacholine test defined as PC20
8 mg/ml.
- Variability < 20% of the PEFR values."
COPD
Those patients with an FEV1 of 
70% of the predicted value and who had a reversibility of less than 15% after administration of ß2-agonist or after 2 weeks of treatment with oral steroids (all of them smokers or ex-smokers, non of them were atopics), and with no other diagnosed disease that could explain the results, were classified as COPD patients.8
Those cases where the results were close to asthma and COPD at the same time were diagnosed as ‘asthma and COPD'. The typical patient had an atopic proved by SPT, smoker or ex-smoker, an FEV1 of 68% of that predicted and a reversibility of 18% after administration of oral steroids.
The study was approved by the regional ethics committee.
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Results |
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One hundred and twenty-three patients fulfilled the criteria for inclusion in the study and were called for examination. Ninety-seven patients (79%) turned up for the appointment. Of the 26 patients who did not, two had demense, four had moved from the district, three refused and 17 did not answer a telephone call. Eleven out of those 97 patients who attended could not fulfil the examination. The reasons for this were demense (one case), obvious language difficulties in immi-grants (two cases), a change of mind about participating (four cases) and other reasons, such as moving from the district during the study period (four cases). The final study group comprised 86 patients, 54 of them females.
As shown in Table 2, 51 out of 86 patients (59%) had asthma and six patients (7%) had asthma in combination with COPD. Fifteen patients (17%) had COPD without asthma, and three patients (3%) had another lung disease (bronchitis or old changes from tuberculosis). In 11 cases (13%), no lung disease could be detected. Those patients in whom no lung disease could be diagnosed had cardiac failure, functional breathing disorder or panic disorder.
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As far as asthma is concerned, the accuracy of previous diagnosis was best in subjects aged 50 years or younger (Table 3
). Of those aged over 50 years, 47% had been given the wrong diagnosis.
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In out-patients, the diagnosis of bronchial asthma had previously been made in 55 cases and in hospitalized patients in 31 cases. The wrong diagnosis had been made in 21 of the 55 out-patients (38%) and in 8 out of the 31 hospitalized patients (26%).
Analysis of onset of the disease showed that eight patients (9%) had been misdiagnosed for 10 years or more (Table 4). The wrong diagnosis had been made for 36% of the women, compared with 29% of the men.
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Discussion |
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This study is based on all patients with the diagnosis bronchial asthma who had consulted two GPs during a defined period. A ‘2-year' search is believed to include most of the patients with the diagnosis bronchial asthma.
Differential diagnostics as concern bronchial asthma are sometimes difficult.9–11 One of the most important, most common and most difficult differential diagnoses in bronchial asthma is COPD.11 The incidence of this disease has increased dramatically during the last few years, especially in women.12 Even if it is easy to describe different criteria for different diseases in general terms, the single case is often difficult to classify, especially when the patient fulfils the criteria for both COPD and asthma. Those patients found to have COPD or the combination of asthma and COPD may originally have had airway reversibility (i.e. correct diagnosis of asthma), but this reversibility may have been lost with time. This study showed that all of those with COPD were more than 50 years old, with only one exception. Most subjects were more than 60 years old (12 out of 15).
As concerns differential diagnosis, the diagnosis that increasingly has been taken into consideration is FBD.10 In this study, about 10% of all those who had been informed that they had asthma had, according to the re-evaluation, the diagnosis of FBD. The patient describes symptoms which are very close to those of asthma. A careful examination, like the one described in this study, is unable to show any reversibility of the lung function, not even when the patient has stopped taking his/her asthma drugs.
To summarize, every third ‘asthmatic' had been given the wrong diagnosis. The older the patient, the bigger the risk for the wrong diagnosis. These facts ought to motivate us always to reconsider the diagnosis. This proposal is relevant to out-patients as well as hospitalized patients.
Of course, a wrong diagnosis can be a problem from a medical point of view. Even if patients with bronchial asthma and those with COPD have the same type of drugs, the treatment in the emergency room can make the difference between life or death. If you treat a patient with COPD like a ‘known asthmatic' by prescribing him/ her oxygen, it can lead to a dangerous retention of carbon dioxide. It is also to be expected that those diagnosed to have asthma, although they have COPD, have inhaled more steroids than their small reversibility motivates.
Wrong treatment due to a wrong diagnosis will also have economical consequences. There is reason to believe that great amounts of inhaled steroids are prescribed to so-called ‘asthmatics' with no effect on their true disease.
We think it is important not to underestimate the psychological consequences of misdiagnosis of a chronic and potentially life-threatening disease. According to our knowledge this is not studied for asthma, but studies of other chronic diseases indicate that the wrong diagnosis will have negative psychological consequences.13 Insecurity as concerns course, prognosis and treatment is common. Information about having a chronic disease also often means a threat to the patient's identity.
This study has analysed a limited number of patients from two consultant receptions of two GPs. There is reason to be cautious when generalizing the results of this study. We want to emphasize, however, the importance of a secure and correct diagnosis in a patient with symptoms of bronchial asthma. A correct diagnosis of bronchial asthma should be the evidence base for treating the patient and also for developing quality in the handling of asthma patients. This study indicates that more accuracy is needed when diagnosing bronchial asthma—in out-patients as well as in hospitalized patients.
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Acknowledgments |
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We wish to thank the GPs C-P Anderberg, C Lütz, D Norberg, R Larsson, the specialist in asthma and allergologist O Löwhagen, and the nurse I Jahn, who so carefully contributed to the outcome of this study.
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References |
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1 Torén K, Hermansson R. Increased incidence rate of physician-diagnosed asthma among female smokers. Am J Respir Crit Care Med 1995; 151: a31.
2 Björnsson E, Plaschke P, Norrman E et al. Symptoms related to asthma and chronic bronchitis in three areas of Sweden. Eur Respir J 1994; 7: 2146–2153.[Abstract]
3 Speight AN. Is childhood asthma being underdiagnosed and undertreated? Br Med J 1978; 2: 331–332.
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Kolnaar B, Beissel E, Bosch WHJMv, Folgering HTM, Hoogen HJMv, Weel Cv. Asthma in adolescents and young adults: screening outcome versus diagnosis in general practice. Fam Pract 1994; 11: 133–140.
5 Tirimanna PRS, Schayck CPv, Otter JJd et al. Prevalence of asthma and COPD in general practice: has it changed since 1977? Br J Gen Pract 1996; 46: 277–281.[Web of Science][Medline]
6 Ringsberg KC, Löwhagen O, Sivik T. Psychological differences between asthmatics and patients suffering from an asthma-like condition, Functional Breathing Disorder: A comparison between the two groups concerning personality, psychosocial and somatic parameters. Integr Physiol Behav Sci 1993; 28: 358–367.[Web of Science][Medline]
7 Ringsberg KC et al. Physical capacity and dyspnoea in patients with asthma-like symptoms but negative asthma tests. Allergy 1997; 52: 532–540.[Web of Science][Medline]
8 Siafakas SM, Vermiere P, Pride NB et al. Optimal assessment and management of chronic obstructive pulmonary disease (COPD): European Respiratory Society consensus statement. Eur Respir J 1995; 8: 1398–1420.[Web of Science][Medline]
9 National Heart, Lung and Blood Institute, National Institute of Health, Bethesda, Maryland, USA. Global strategy for asthma management and prevention. NHLBI/WHO, Workshop report, Publication No. 95-3659, Jan. 1995.
10 Skedinger M, Brundin A, Hermansson BA. Investigation when suspecting asthma. In Larsson, K (ed.). Asthma: Clinic and Treatment. Lund Draco Läkemedel AB, 1985: 169–185.
11 Löfgren L, Struwe I. Differential diagnostics as concern bronchial asthma. In Larsson, K (ed). Asthma: Clinic and Treatment. Lund Draco Läkemedel AB, 1985: 187–197.
12 Jacobson L, Lindgren B. COPD—Economical Costs of Society, University of Lund. Studies Health Econ 1995; 9: 18–22.
13 Strauss AL, Corbin J, Fagerhaugh S et al. Chronic Illness and the Quality of Life. 2nd edn. St Louis: CV Mosby, 1984.
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