Belgian Pulmonary Function Study

Study Overview
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Brief Summary
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Pulmonary function tests including spirometry, lung volumes, measurements of resistance and diffusing capacity are essential in the diagnosis of several pulmonary diseases. These tests are an integral part of the diagnosis and treatment of lung diseases, but until now there is no clear evidence for the use of many of the pulmonary function tests because of a lack of adequate studies. The obscurity largely pertains to the conditions under which combinations of the various tests are indicated. Therefore the Belgian Thoracic Society, assembling all pulmonologists and the pneumology LOK/GLEMs, will investigate this matter.

Official Title
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Belgian Pulmonary Function Study : the Belgian Thoracic Society

Conditions
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Respiratory Symptoms

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Males and females Age between 18 and 75 years old New outpatients with respiratory symptoms as dyspnoea, cough, sputum, but without firm diagnosis Results of the tests are available and acceptable Standardized list of complaints Capability of patient for doing pulmonary function tests Seen by a Pneumologist Written informed consent Exclusion Criteria: Patients with diagnosed respiratory disease Younger than 18 and older than 75 years old Recent heart attack Pneumothorax hemoptoic Suspicion of Tuberculosis Not capable to do pulmonary function tests

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 75 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Caucasian outpatients with respiratory symptoms<br>all consecutive new Caucasian outpatients with respiratory symptoms like dyspnoea, cough, sputum but without diagnosis who are being examined for the first time. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| pulmonary function tests (spirometry, volumes, resistance and diffusing capacity in that order) on the preferential diagnosis. | To determine the effect of stepwise addition of various pulmonary function tests (spirometry, volumes, resistance and diffusing capacity in that order) on the preferential diagnosis and its reflection of the gold standard (final diagnosis), a statistical score will be calculated based on 1/n differential diagnoses after every pulmonary function test. The score will contain corrections for a high number of differential diagnoses and a wrong preferential diagnosis and compared with Linear mixed model after logistic transformation. | end of study | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| % correct preferential diagnoses | To determine the effect of stepwise addition of various pulmonary function tests (spirometry, volumes, resistance and diffusing capacity in that order) on preferential diagnoses and their reflection of the gold standard (final diagnosis), the number and percentage of correct preferential diagnoses will be analysed after every pulmonary function test and compared by a generalized estimating equation model (GEE) | end of study | 
| N differential diagnoses in the subgroup with correct preferential diagnosis | To determine the effect of stepwise addition of various pulmonary function tests (spirometry, volumes, resistance and diffusing capacity in that order) on the number of differential diagnoses and their reflection of the gold standard (final diagnosis), the number of differential diagnoses in patients with correct preferential diagnosis will be analysed after each pulmonary function test and compared with Poisson GEE | end of study | 
| subgroup analyses | The primary endpoint (1/n differntial diagnoses) and 2 secondary endpoints (% correct preferential diagnoses, n differential diagnoses within correct preferential diagnosis) will be analysed in subgroups with final gold standard diagnosis of COPD, asthma, interstitial lung disease and  no pulmonary abnormality | end of study | 
| Sensitivity analysis | Primary endpoint (1/n differntial diagnoses) and 2 secondary endpoints (% correct preferential diagnoses, n differential diagnoses within correct preferential diagnosis) and subgroup analyses (asthma, COPD, interstitial lung disease and no primary pulmonary abnormality) will be evaluated not only considering final diagnosis as standard but als correct side diagnosis | end of study | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Caucasian outpatients, undiagnosed respiratory symptoms, dyspnea, cough, sputum