Early Diagnosis Of Asymptomatic Chronic Obstructive Pulmonary Disease (COPD) Patients

PrefaceAsymptomatic chronic obstructive pulmonary disease ( COPD) means that COPD patients have no symptoms ,but they really have airflow limitation according to pulmonary function test and can diagnosed with COPD. They seldom went to hospital because of no symptoms. However they are easy to diagnose with COPD in epidemic survey.Our survey shows that the asymptomatic COPD patients really exist. Most of them belong to early stage of COPD - stage â…  ( mild) and stage â…¡ ( moderate ). They are difficult to diagnose because of no differential clinical manifestation. Pulmonary function test is gold standard of diagnosis. FEV₁/FVC can reflect mild airflow limitation and can make diagnosis even in early stage of disease. But can only single pulmonary function test diagnose asymptomatic COPD ? How is the reliability? There were few studies about this . The aim of present study is to survey the presence and early diagnosis of asymptomatic COPD. The early diagnosis of asymptomatic COPD should be possible and obejective.Object and instrumentWe have survryed in Heishan in September,2003 and Yuhong in August , 2004. Ninty cases of asymptomatic COPD were found. We surveyed them again in December,2005 and in April ,2006. The data of 69 asymptomatic COPD patients were collected.Instrument:Microloopl. 07 pulmonary function instrument, IL - 8 ELASA. kit,LD4 -2A low rate zentrifugen, Microplate reader.MethodsInformation of questionare and symptom were obtained, physical examination and pulmonary function test were performed, vein blood were drawn. It was the same people who take part in the survey for two times. We use the same pulmonary function instrument in the second survey. All instruments should be test and standarize. We test pulmonary function for three times and save the best one. The patients whose FEVj/FVC <70% and ameliorating rate < 15% after inhaling Shadinganchun 400ug were diagnosed with COPD excluding other card-iovescular and pulmonary disease.ELASA test were performed in testing Serum IL - 8.ResultsThe information of 69 cases of asymptomatic COPD patients were obtained , while missing ones were 21 cases. In the asymptomatic COPD patients, 36 males and 33 females ,the mean age was 64.2 ±9.7 years,there were 36 cases 52. 17% (36/69) ( named as deteriorating group) whose pulmonary function were deteriorating;and 33 cases 47. 83% (33/69) (named as ameliorating group) whose pulmonary function were ameliorating. There was statistical difference in these two groups in FEVj/FVC. This means the dynamical change in two groups FEV,/FVC was the most prominent and sensitive. The FEV, of asymptomatic COPD patients was correlated with smoking years,r = -0. 949( P =0. 014 <0. 05 ) . Serum IL - 8 level was 380. 19 ±217. 56pg/ml. FEV/FVC was correlated with IL - 8.DiscussionThe asymptomatic COPD patients really exist by epidemic survey. EarlyCOPD patients have or not have symptoms when only mild airway limitation exit. But pulmonary function test is sensetive to diagnose airway limitation and gold standard of diagnosing COPD. They have no typical clinical manifestation. But can only single pulmonary function test make diagnosis? We survey asymptomatic COPD patients for the second time after 27 months. There were 36 cases 52. 17% (36/69) (Deteriorating group) whose pulmonary function were deteriorating;while 33 cases 47. 83% (33/69) (ameliorating group) whose pulmonary function were ameliorating and they cant diagnosed COPD as their FEV,/FVC > 70%. What's the reason? Maybe as follows:1. Most asymptomatic COPD patients belong to early stage of COPD - stage I and stage II ( approximately 71% ). The early pathology can be reversed .Smoking is the definite risk factor of COPD. Quitting smoking can ameliorate pulmonary function. The FEVj was correlated with smoking years ,r = - 0. 949 ( P = 0. 014). Lower airway bacterial colonization ( LABC) was correlated with progressive airflow limitation . Increaced bacterial quantity and variance of bacterial was correlated with decrease of pulmonary function. Even stable COPD have LABC. So FEVj/FVC may be related to children'and recently respiratory infection especially AECOPD .2. The asymptomatic COPD patients' pathogenesis :The acute exacerbation of COPD make infiltratoin of inflammatory cell and expression of cytokine . But stable COPD shows enhance of airway inflammation . This is related to LABC. LABC can make infiltratoin of neutrophils cells and release of cytokine (IL -8 ). There was statistical difference in these two groups in IL -8. FEV,/FVC was correlated with IL - 8.3. Pulmonary function test should gain patients' cooperation and controll quanlity. Spirometry isnt at large. Is cheap instrument perfect? FEV,/FVC et, al test should gain patient' s cooperation. This means that the repeatabilityxsensitivity and specificity are' t perfect.Conclutions1. The asymptomatic COPD patients really exist.2. Pulmonary function test is gold standard of diagnosing COPD. Only single pulmonary function test cant diagnose COPD. It should be observed dynamically.3. The degree of airflow limitation was correlated with smoking, lower airway bacterial colonization ( LABC) and IL - 8 and so on. The decreace of pulmonary function maybe related to smoking .children'respiratory infection and IL-8.