Longitudinal Evaluation of Lung Function Associated with Emphysema in Healthy Smokers / 결핵및호흡기질환

BACKGROUND: Smoking reduces pulmonary function and induces various lung diseases. Recently, the rate of emphysema detection has increased due to lung cancer screening with low-dose chest computed tomography (CT). The purpose of this study was to evaluate changes in lung function associated with emphysema in healthy smokers. METHODS: One hundred and ninety one healthy smokers, who had undergone a low-dose chest CT (LDCT) scan as part of lung cancer screening and had revisited the health center after a median 23.9 months' time, were recruited into this study. The severity of emphysema was calculated by the direct observation of a radiologist and a pulmonologist indipendently. Longitudinal changes in lung function according to emphysema based on LDCT and type of smoker was analyzed. RESULTS: Of the participants in this study, 25% of healthy smokers had emphysema, which was mild in severity, in older patients (p=0.003) and in heavy smokers (p<0.001). FEV1/FVC and FEF25-75% were decreased in current smokers with emphysema (p=0.001 and p=0.009, respectively) and without emphysema (p=0.001 and p=0.042). Although lung function was not decreased in ex-smokers without emphysema, FEV1/FVC and FEF25-75% were decreased in ex-smoker with emphysema (p=0.020 and p=0.010). CONCLUSION: Upon examination with LDCT, the prevalence of emphysema was higher in healthy smokers was than in non-smokers. Lung function was diminished in smokers with emphysema, in spite of former smoker.

Longitudinal Evaluation of Lung Function Associated with Emphysema in Healthy Smokers / 결핵및호흡기질환

BACKGROUND: Smoking reduces pulmonary function and induces various lung diseases. Recently, the rate of emphysema detection has increased due to lung cancer screening with low-dose chest computed tomography (CT). The purpose of this study was to evaluate changes in lung function associated with emphysema in healthy smokers. METHODS: One hundred and ninety one healthy smokers, who had undergone a low-dose chest CT (LDCT) scan as part of lung cancer screening and had revisited the health center after a median 23.9 months' time, were recruited into this study. The severity of emphysema was calculated by the direct observation of a radiologist and a pulmonologist indipendently. Longitudinal changes in lung function according to emphysema based on LDCT and type of smoker was analyzed. RESULTS: Of the participants in this study, 25% of healthy smokers had emphysema, which was mild in severity, in older patients (p=0.003) and in heavy smokers (p<0.001). FEV1/FVC and FEF25-75% were decreased in current smokers with emphysema (p=0.001 and p=0.009, respectively) and without emphysema (p=0.001 and p=0.042). Although lung function was not decreased in ex-smokers without emphysema, FEV1/FVC and FEF25-75% were decreased in ex-smoker with emphysema (p=0.020 and p=0.010). CONCLUSION: Upon examination with LDCT, the prevalence of emphysema was higher in healthy smokers was than in non-smokers. Lung function was diminished in smokers with emphysema, in spite of former smoker.

Immunohistochemical Expression and Prognostic Value of VEGF, HIF-1alpha, EGFR in Non-Small Cell Lung Cancer / 결핵및호흡기질환

BACKGROUND: Vascular endothelial growth factor (VEGF) is a potent mediator of angiogenesis. VEGF production is regulated by HIF-1alpha and EGFR. This study examined the relationship between the clinicopathological factors and VEGF, HIF-1alpha and EGFR protein overexpression, and evaluated their prognostic value in patients with a surgically resected non-small cell lung cancer (NSCLC). METHODS: Patients who underwent a surgical resection at Kangnam St. Mary's hospital were reviewed retrospectively. The core biopsy samples from 54 patients with NSCLC were assembled on a tissue microarray (TMA), and immunohistochemical staining for the VEGF, HIF-1alpha and EGFR proteins was performed. The overexpression of these proteins was evaluated in relation to age, gender, histology and staging by univariate analysis. The clinicopathological prognostic factors were analyzed. RESULTS: Multivariate analysis performed by Cox regression (odds ratio 2.8, 95% CI 1.0~8.2, p=0.046) revealed HIF-1alpha overexpression to be an unfavorable factor. There was no correlation between the overexpression of these proteins and the clinicopathological factors. VEGF showed a positive relationship with EGFR, but there was no statistical significance [p(chi2)=0.06]. CONCLUSION: HIF-1alpha overexpression predicts shorter survival in patients with a surgically resected NSCLC. Therefore, HIF-1alpha may be a poor prognostic factor in NSCLC.

Inhibitory effect of CXC chemokine receptor 4 antagonist AMD3100 on bleomycin induced murine pulmonary fibrosis

CXC chemokine receptor 4 (CXCR4), which binds the stromal cell-derived factor-1 (SDF-1), has been shown to play a critical role in mobilizing the bone marrow (BM)-derived stem cells and inflammatory cells. We studied the effects of AMD3100, CXCR4 antagonist, on a murine bleomycin-induced pulmonary fibrosis model. Treatment of mice with AMD3100 in bleomycin-treated mice resulted in the decrease of SDF-1 in bronchoalveolar lavage (BAL) fluids at an early stage and was followed by the decrease of fibrocytes in the lung. AMD3100 treatment decreased the SDF-1 mRNA expression, fibrocyte numbers in the lung at an early stage (day 3) and CXCR4 expression at the later stage (day 7 and 21) after bleomycin injury. The collagen content and pulmonary fibrosis were significantly attenuated by AMD3100 treatment in later stage of bleomycin injury. AMD3100 treatment also decreased the murine mesenchymal and hematopoietic stem cell chemotaxis when either in the stimulation with bleomycin treated lung lysates or SDF-1 in vitro. In BM stem cell experiments, the phosphorylation of p38 MAPK which was induced by SDF-1 was significantly blocked by addition of AMD3100. Our data suggest that AMD3100 might be effective in preventing the pulmonary fibrosis by inhibiting the fibrocyte mobilization to the injured lung via blocking the SDF-1/CXCR4 axis.

Relationship between Arousal Indices and Clinical Manifestations in Patients Who Performed Polysomnography / 결핵및호흡기질환

BACKGROUND: Repeated arousals during sleep have been known to be associated with excessive daytime sleepiness and cardiovascular complications. We investigated the relationship between arousal indices and clinical parameters. METHODS: We retrospectively reviewed medical records of 41 patients who performed polysomnography for a diagnosis of obstructive sleep apnea syndrome. We defined total arousal index (TAI) as the number of arousals per hour and respiratory arousal index (RAI) as the number of arousals associated with apnea or hypopnea per hour. RESULTS: There were significant positive correlations between arousal indices and apnea-hypopnea index (AHI) (RAI vs. AHI, r=0.958, p<0.001; TAI vs. AHI, r=0.840, p<0.001). RAI and mean oxygen saturation showed a significant negative correlation with each other (r=-0.460, p=0.002). TAI revealed a significant positive correlation with mean systolic blood pressure (MSBP) and mean diastolic blood pressure (MDBP) (TAI vs. MSBP, r=0.389, p=0.014; TAI vs. MDBP, r=0.373, p=0.019). There was no significant correlation between arousal indices and parameters of sleepiness. RAI had a significant positive correlation with body mass index (BMI) and neck circumference (NC) (RAI vs. BMI, r=0.371, p=0.017; RAI vs. NC, r=0.444, p=0.004). When partial correlation analysis was performed to adjust for other variables, there was significant correlation between RAI and AHI (r=0.935, p<0.001). CONCLUSION: This study shows that respiratory arousal index could be a useful index reflecting of severity of obstructive sleep apnea syndrome. Arousal during sleep would be concerned in the development of cardiovascular complication of obstructive sleep apnea. And some anthropometric factors would contribute to the development of arousals during sleep. Further studies are needed to clarify any cause-effect relationship.

A Case of Sarcoidosis That Was Initially Misdiagnosed as Nontuberculous Mycobacteria Pulmonary Disease / 결핵및호흡기질환

There are several respiratory diseases that show chronic granulomatous inflammation for the histologic finding. Among them, sarcoidosis and tuberculosis are not easy to differentiate when the clinical and radiological features present similar patterns. The increasing incidence of nontuberculous mycobacteria pulmonary disease is making it more difficult for clinicians to arrive at a proper diagnosis. A 69 year old male patient visited our hospital with chronic cough as his chief compliant. His radiologic findings were multiple enlarged mediastinal lymphadenpathies with innumerable micronodules and multiple patch infiltrations. The spleen biopsy finding showed chronic granulomatous inflammation, and Mycobacterium avium was identified on the bronchoscopic culture. Because of these findings, we treated him with drugs for nontuberculous mycobacteria disease other than sarcoidosis. However, during the treatment, his symptoms and radiological features became aggravated. Thus, we reviewed the radiologic and pathologic findings and decided to treat him with steroid, which relieved his symptoms and improved the radiologic findings. We report here on a case of sarcoidosis that was initially misdiagnosed as nontuberculous mycobacteria pulmonary disease.

The Soluble Tumor Necrosis Factor-Alpha Receptor Suppresses Airway Inflammation in a Murine Model of Acute Asthma

PURPOSE: Tumor necrosis factor-alpha (TNF-alpha) is a proinflammatory cytokine that has been implicated in many aspects of the airway pathology in asthma. TNF-alpha blocking strategies are now being tried in asthma patients. This study investigated whether TNF-alpha blocking therapy inhibits airway inflammation and airway hyperresponsiveness (AHR) in a mouse model of asthma. We also evaluated the effect of TNF-alpha blocking therapy on cytokine production and adhesion molecule expression. MATERIALS AND METHODS: Ovalbumin (OVA) sensitized BALB/c female mice were exposed to intranasal OVA administration on days 31, 33, 35, and 37. Mice were treated intraperitoneally with soluble TNF-alpha receptor (sTNFR) during the OVA challenge. RESULTS: There were statistically significant decreases in the numbers of total cell and eosinophil in bronchoalveolar lavage fluid (BALF) in the sTNFR treated group compared with the OVA group. However, sTNFR-treatment did not significantly decrease AHR. Anti-inflammatory effect of sTNFR was accompanied with reduction of T helper 2 cytokine levels including interleukin (IL)-4, IL-5 and IL-13 in BALF and vascular cell adhesion molecule 1 expression in lung tissue. CONCLUSION: These results suggest that sTNFR treatment can suppress the airway inflammation via regulation of Th2 cytokine production and adhesion molecule expression in bronchial asthma.

A Case of Chronic Expanding Hematoma with Initial Presentation as Massive Hemotpysis through Bronchopleural Fistula in the Thorax / 결핵및호흡기질환

Chronic expanding hematoma of the thorax is a specific subtype of the chronic empyema. It presents as a slowly expanding intrathoracic mass which result in dyspnea or recurrent hemoptysis. The symptoms develop months or years after tuberculous pleurisy, trauma or surgery. Usually, it shows three common findings: a giant mass lesion in the thorax, some surrounding calcifications, the absence of signs or symptoms of infection. We report a case of chronic expanding hematoma of the thorax, initially presenting as massive hemoptysis through bronchopleural fistula which resulted in radiologic findings of new air-fluid level within the previous pleural lesion filled with unknown materials.

IP-10 Decreases TNF-alpha Induced MUC5AC Expression in Human Airway Epithelial Cells: a Possible Relation with Little Sputum Production in Idiopathic Pulmonary Fibrosis / 결핵및호흡기질환

BACKGROUND: IPF is characterized by chronic, fibrosing inflammatory lung disease of unknown etiology. Typical symptoms of IPF are exertional dyspnea with nonproductive cough. Why patients with typical IPF have dry cough rather than productive cough, is unknown. IP-10 plays an important regulatory role in leukocyte trafficking into the lung. The present study investigated the effect of IP-10 in the pathogenesis of dry cough rather than productive cough in IPF patients. METHODS: IP-10 concentration was measured by ELISA from BALF of IPF patients. To evaluate the role of IP-10 in mucin expression, the expression of the MUC5AC mucin gene was measured in NCI-H292 cells, a human pulmonary mucoepidermoid carcinoma cell line, after stimulation by TNF-alpha with or without IP-10 pretreatment. EGFR-MAPK expression was also examined as a possible mechanism. RESULTS: IP-10 levels were significantly higher in the BALF of IPF patients compared to healthy controls. IP-10 pretreatment reduced TNF-alpha induced MUC5AC mucin expression by inhibiting the EGFR-MAPK signal transduction pathway in NCI-H292 cells. CONCLUSION: These findings suggest that little mucus production in IPF patients might be attributable to IP-10 overproduction, which inhibits the EGFR-MAPK signal transduction pathway required for MUC5AC mucin gene expression.

Prognostic Value of Vascular Endothelial Growth Factor (VEGF) and Basic Fibroblast Growth Factor (bFGF) Expression in Resected Non-small Cell Lung Cancer / 결핵및호흡기질환

BACKGROUND: Tumor angiogenesis plays an important role in tumor growth, maintenance and metastatic potential. Tumor tissue produces many types of angiogenic growth factors. Vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) have both been implicated to have roles in tumor angiogenesis. In this study, the expression of tissue VEGF and bFGF from non-small cell lung cancer (NSCLC) patients were analyzed. METHODS: We retrospectively investigated 35 patients with a histologically confirmed adenocarcinoma or squamous cell carcinoma of the lung, where the primary curative approach was surgery. An ELISA was employed to determine the expression of VEGF and bFGF in extracts prepared from 35 frozen tissue samples taken from the cancer patients. RESULTS: VEGF and bFGF concentrations were significantly increased in lung cancer tissue as compared with control (non-cancerous) tissue. The VEGF concentration was significantly increased in T2 and T3 cancers as compared with T1 cancer. Expression of VEGF was increased in node-positive lung cancer tissue as compared with node-negative lung cancer tissue (p=0.06). VEGF and bFGF expression were not directly related to the stage of lung cancer and patient survival. CONCLUSION: Expression of VEGF and bFGF were increased in lung cancer tissue, and the expression of VEGF concentration in lung cancer tissue was more likely related with tumor size and the presence of a lymph node metastasis than the expression of bFGF. However, in this study, expression of both VEGF and bFGF in tissue were not associated with patient prognosis.

A Case of Colon Obstruction Developed as a Complication of Acute Pancreatitis / 대한소화기학회지

In acute pancreatitis, colonic complications such as mechanical obstruction, ischemic necrosis, hemorrhage, and fistula are rare but their outcomes are fatal. It is known that colonic obstruction in acute pancreatits is more likely found in splenic flexure and transverse colon caused by severe inflammation of body and tail of pancreas leading to pressure necrosis. A 43-year-old man presented with abdominal distension lasting for 2 weeks. The patient had been admitted to our institution 6 weeks prior to the current admission, and the abdominal CT scan performed during the first admission revealed the pancreatic enlargement with peri-pancreatic fatty infiltration and fluid collection. At that time he was diagnosed as acute pancreatitis. The conservative management resulted in clinical improvent so that the patient was discharged. Upon the second admission, abdominal CT scan revealed multiple pseudocysts in the tail portion of pancreas with concominant wall thickening and narrowing of the proximal descending colon, and a dilatation of the bowel proximal to the splenic flexure. An obstruction of the descending colon as a complication of acute pancreatitis was suspected and the patient underwent left hemicolectomy. Abdominal distension was relieved after the operation and he was discharged on the 15th hospital days.

Extranodal Marginal Zone Lymphoma Occurring along the Trachea and Central Airway

Extranodal marginal zone lymphoma is a low-grade B cell lymphoma that presents with an indolent clinicopathologic nature. Although this tumor can occur in various sites, including the gastrointestinal tract and lungs, it develops and spreads extremely rarely along the trachea and central airway. We report a case of extranodal lymphoma of mucosa-associated lymphoid tissue with tracheobronchial involvement. An 83-year-old woman presented with a cough and dyspnea. Bronchoscopic evaluation confirmed diffuse, multiple nodular lesions in both the trachea and large bronchi, and she was diagnosed with an extranodal marginal zone lymphoma of the tracheobronchial tree. After systemic chemotherapy, she survived for more than 18 months.

Utility of B-type Natriuretic Peptide in Patients with Acute Respiratory Distress Syndrome / 결핵및호흡기질환

BACKGROUND: B-type natriuretic peptide (BNP) has been shown to be strong mortality predictors in a wide variety of cardiovascular syndromes. Little is known about BNP in patients with acute respiratory distress syndrome (ARDS). We studied whether BNP can predict mortality in patients with ARDS. METHOD: Echocardiographic study was done to all patients with ARDS, and we excluded patient with low ejection fraction (less than 50%) or showing any features of diastolic dysfunction. 47 patients were enrolled between December, 2003 and February, 2006. Parameters including BNP were obtained within 24h hours at the time of enrollment. RESULT: Mean BNP concentrations and APACHE II scores differed between the survivors and nonsurvivors (BNP, 219.5 +/- 57.7 pg/mL vs 492.3 +/- 88.8 pg/mL; p=0.013, APACHE II score, 17.4 +/- 1.6 vs 23.1 +/- 1.3, p=0.009, respectively). With the use of the threshold value for BNP of 585 pg/mL, the specificity for the prediction of mortality was 94%. The threshold value for APACHE II of 15.5 showed sensitivity of 87%. 'APACHE II + 11xlogBNP' showed sensitivity 63%, and specificity 82%, using threshold value for 46.14. CONCLUSION: BNP concentrations and APCHE II scores were more elevated in nonsurvivors than survivors in patients with ARDS who have normal ejection fraction. BNP can predict mortality. Further study should be done.

Clinical and Radiological Characteristics of Non-Tuberculous Bronchial Anthracofibrosis / 결핵및호흡기질환

BACKGROUND: Bronchial anthracofibrosis, which is defined as bronchial narrowing with black pigmentation of the overlying bronchial mucosa, is frequently associated with tuberculosis. The aim of this study was to examine the relationship between bronchial anthrocofibrosis and to identify the clinical and radiological characteristics of non-tuberculous bronchial anthracofibrosis. METHODS: All patients who showed bronchial anthracofibrosis in more than one segment on a bronchoscopic examination from January 2003 to July 2006 at Kangnam St. Mary's hospital were enrolled in this study. The underlying diseases, baseline clinical characteristics, characteristic findings on a computed tomogram (CT) of the chest, pathologic findings of the bronchial mucosa, and the clinical response to steroid therapy were analyzed retrospectively. RESULTS: A total 54 patients (19 males, 35 females) were enrolled with a mean age of 75 years. The most common presenting symptoms were cough, sputum and dyspnea. The predominant X-ray findings were peribronchial soft tissue attenuation with or without calcification, mediastinal lymphadenopathy with or without calcification and atelectasis. Fourteen non-tuberculous anthracofibrosis patients were treated with steroid. Nine patients were improved clinically, and 6 patients were improved radiologically. CONCLUSION: Bronchial anthracofibrosis is frequently associated with various pulmonary diseases not only tuberculosis but also COPD pneumonia etc.

Clinical and Radiological Characteristics of Non-Tuberculous Bronchial Anthracofibrosis / 결핵및호흡기질환

BACKGROUND: Bronchial anthracofibrosis, which is defined as bronchial narrowing with black pigmentation of the overlying bronchial mucosa, is frequently associated with tuberculosis. The aim of this study was to examine the relationship between bronchial anthrocofibrosis and to identify the clinical and radiological characteristics of non-tuberculous bronchial anthracofibrosis. METHODS: All patients who showed bronchial anthracofibrosis in more than one segment on a bronchoscopic examination from January 2003 to July 2006 at Kangnam St. Mary's hospital were enrolled in this study. The underlying diseases, baseline clinical characteristics, characteristic findings on a computed tomogram (CT) of the chest, pathologic findings of the bronchial mucosa, and the clinical response to steroid therapy were analyzed retrospectively. RESULTS: A total 54 patients (19 males, 35 females) were enrolled with a mean age of 75 years. The most common presenting symptoms were cough, sputum and dyspnea. The predominant X-ray findings were peribronchial soft tissue attenuation with or without calcification, mediastinal lymphadenopathy with or without calcification and atelectasis. Fourteen non-tuberculous anthracofibrosis patients were treated with steroid. Nine patients were improved clinically, and 6 patients were improved radiologically. CONCLUSION: Bronchial anthracofibrosis is frequently associated with various pulmonary diseases not only tuberculosis but also COPD pneumonia etc.

Inflammatory and Remodeling Events in Asthma with Chronic Exposure to House Dust Mites: A Murine Model

Although animal models with ovalbumin have been used to study chronic asthma, there are difficulties in inducing recurrence as well as in maintaining chronic inflammation in this system. Using a murine model of house dust mite (HDM)-induced bronchial asthma, we examined the airway remodeling process in response to the chronic exposure to HDM. During the seventh and twelfth weeks of study, HDM were inhaled through the nose for three consecutive days and airway responsiveness was measured. Twenty-four hours later, bronchoalveolar lavage and histological examination were performed. The degree of overproduction of mucus, subepithelial fibrosis, and the thickness of the peribronchial smooth muscle in the experimental group was clearly increased compared to the control group. In addition, HDM-exposed mice demonstrated severe airway hyperreactivity to methacholine. In the bronchoalveolar lavage fluid, the number of total cells and eosinophils was increased; during the twelfth week, the number of neutrophils increased in the experimental group. With regard to changes in cytokines, the concentrations of IL-4, IL- 13, and transforming growth factor-beta (TGF-beta) were increased in the experimental group. The data suggest that eosinophils, IL-4, IL-13, and TGF-beta might play an important role in the airway remodeling process and that neutrophils may be involved with increased exposure time.

Time Sequence of Airway Remodeling in a Mouse Model of Chronic Asthma: the Relation with Airway Hyperresponsiveness

During the course of establishing an animal model of chronic asthma, we tried to elucidate the time sequence of airway hyperresponsiveness (AHR), airway inflammation, airway remodeling, and associated cytokines. Seven-week-old female BALB/c mice were studied as a chronic asthma model using ovalbumin (OVA). After sensitization, mice were exposed twice weekly to aerosolized OVA, and were divided into three groups depending on the duration of 4 weeks, 8 weeks, and 12 weeks. At each time point, airway responsiveness, inflammatory cells, cytokines in bronchoalveolar lavage fluids (BALF), serum OVA-specific IgE, IgG1, IgG2a, and histological examination were carried out. AHR to methacholine, increased levels of OVA-specific IgG1 and IgG2a, and goblet cell hyperplasia were continuously sustained at each time point of weeks. In contrast, we observed a time-dependent decrease in serum OVA-specific IgE, BALF eosinophils, BALF cytokines such as IL-13, transforming growth factor-beta1, and a time-dependent increase in BALF promatrix metalloproteinase-9 and peribronchial fibrosis. In this OVA-induced chronic asthma model, we observed airway remodelings as well as various cytokines and inflammatory cells being involved in different time-dependent manners. However, increased airway fibrosis did not directly correlate with a further increase in airway hyperresponsiveness.

Diffuse Nodular Interstitial Infiltrations with Bilateral Hilar Lymphadenopathy / 결핵및호흡기질환

Lymphocytic interstitial pneumonia(LIP) is an uncommon condition in which the alveolar septa and extra-alveolar interstitial space are markedly expanded by small lymphocytes, plasma cells and histiocytes. Chest radiographs generally show nonspecific patterns with the most common pattern showing bibasilar reticular or reticulonodular infiltrates. Hilar or mediastinal lymphadenopathy and pleural effusions are usually absent. We encountered a 42-year-old female patient who was admitted to hospital because of exertional dyspnea and palpitation. The chest X-ray showed an enlarged bilateral hilar shadow and diffusely increased bronchovascular markings in both lung fields. The chest CT showed diffuse nodular infiltrations with mild septal thickening and combined patchy ground glass opacity in both lungs, and conglomerated mediastinal and bilateral hilar lymphadenopathy. A diagnosis of LIP was made from the tissue pathology taken by a thoracoscopic lung biopsy. The patient showed clinical and radiographic improvement after 3 months of treatment with prednisolone. We report a case of LIP presenting as diffuse nodular interstitial infiltrations with multiple mediastinal and bilateral hilar lymphadenopathy.

A Case of Tracheal Diverticula in a Hemoptysis Patient with Tuberculosis Sequela and Fungus Ball / 결핵및호흡기질환

We experienced a rare case of trachea diverticula combined with the sequela of tuberculosis and a fungus ball. The patient had complained of coughing and hemoptysis for a long time after experiencing tuberculosis. He was admitted due to hemoptysis and the aggravation of coughing. The CT scan showed a variable sized trachea diverticula combined with tuberculosis sequela and a fungus ball in the right lung fields. The diagnosis was made by bronchoscopy and a CT scan. After bronchial artery embolization and conservative treatment, the patient's symptoms improved and the patient was discharged.

Analysis of Sleep Questionnaires of Patients who Performed Overnight Polysomnography at the University Hospital / 결핵및호흡기질환

BACKGROUND: The objective of this study was to understand sleep-related problems, and to determine whether the sleep questionnaires is a clinically useful method in patients who need polysomnography. METHODS: Subjects were patients who performed polysomnography and who asked to answer a sleep questionnaires at the Sleep Disorders Clinic of St. Paul's Hospital, Catholic University of Korea. Baseline characteristics, past medical illness, behaviors during sleep-wake cycle, snoring, sleep-disordered breathing and symptoms of daytime sleepiness were analyzed to compare with data of polysomnography. RESULTS: The study population included 1081 patients(849 men, 232 female), and their mean age was 44.2+/-12.8 years. Among these patients, 38.9% had an apnea-hypopnea index(AHI) < 5, 27.9% had 5 < or = AHI < 20, 13.2% had 20 < or = AHI < 40, and 20.0% had 40 < or = AHI. The main problems for visiting our clinic were snoring(91.7%), sleep apnea(74.5%), excessive daytime sleepiness(8.0%), insomnia(4.3%), bruxism(1.1%) and attention deficit(0.5%). The mean value of frequency of interruptions of sleep was 1.6 and the most common reason was urination(46.3%). Epworth Sleepiness Scale(ESS) had a weak correlation with AHI(r=0.209, p<0.01). When we performed analysis of sleep questionnaires, there were significant differences in the mean values of AHI according to the severity of symptoms including snoring, daytime sleepiness, taking a nap and arousal state after wake(p<0.05). CONCLUSION: On the basis of statistical analysis of sleep questionnaires, the severity of subjective symptoms such as ESS, snoring, daytime sleepiness and arousal state after wake correlated with the AHI significantly. Therefore the sleep questionnaires can be useful instruments for prediction of the severity of sleep disorder, especially sleep-disordered breathing.