Prediction of Postoperative Lung Function in Lung Cancer Patients Using Machine Learning Models / 결핵및호흡기질환

Background@#Surgical resection is the standard treatment for early-stage lung cancer. Since postoperative lung function is related to mortality, predicted postoperative lung function is used to determine the treatment modality. The aim of this study was to evaluate the predictive performance of linear regression and machine learning models. @*Methods@#We extracted data from the Clinical Data Warehouse and developed three sets: set I, the linear regression model; set II, machine learning models omitting the missing data: and set III, machine learning models imputing the missing data. Six machine learning models, the least absolute shrinkage and selection operator (LASSO), Ridge regression, ElasticNet, Random Forest, eXtreme gradient boosting (XGBoost), and the light gradient boosting machine (LightGBM) were implemented. The forced expiratory volume in 1 second measured 6 months after surgery was defined as the outcome. Five-fold cross-validation was performed for hyperparameter tuning of the machine learning models. The dataset was split into training and test datasets at a 70:30 ratio. Implementation was done after dataset splitting in set III. Predictive performance was evaluated by R2 and mean squared error (MSE) in the three sets. @*Results@#A total of 1,487 patients were included in sets I and III and 896 patients were included in set II. In set I, the R2 value was 0.27 and in set II, LightGBM was the best model with the highest R2 value of 0.5 and the lowest MSE of 154.95. In set III, LightGBM was the best model with the highest R2 value of 0.56 and the lowest MSE of 174.07. @*Conclusion@#The LightGBM model showed the best performance in predicting postoperative lung function.

Revised Korean Cough Guidelines, 2020: Recommendations and Summary Statements / 결핵및호흡기질환

Cough is the most common respiratory symptom that can have various causes. It is a major clinical problem that can reduce a patient’s quality of life. Thus, clinical guidelines for the treatment of cough were established in 2014 by the cough guideline committee under the Korean Academy of Tuberculosis and Respiratory Diseases. From October 2018 to July 2020, cough guidelines were revised by members of the committee based on the first guidelines. The purpose of these guidelines is to help clinicians efficiently diagnose and treat patients with cough. This article highlights the recommendations and summary of the revised Korean cough guidelines. It includes a revised algorithm for the evaluation of acute, subacute, and chronic cough. For a chronic cough, upper airway cough syndrome (UACS), cough variant asthma (CVA), and gastroesophageal reflux disease (GERD) should be considered in differential diagnoses. If UACS is suspected, first-generation antihistamines and nasal decongestants can be used empirically. In cases with CVA, inhaled corticosteroids are recommended to improve cough. In patients with suspected chronic cough due to symptomatic GERD, proton pump inhibitors are recommended. Chronic bronchitis, bronchiectasis, bronchiolitis, lung cancer, aspiration, intake of angiotensin-converting enzyme inhibitor, intake of dipeptidyl peptidase-4 inhibitor, habitual cough, psychogenic cough, interstitial lung disease, environmental and occupational factors, tuberculosis, obstructive sleep apnea, peritoneal dialysis, and unexplained cough can also be considered as causes of a chronic cough. Chronic cough due to laryngeal dysfunction syndrome has been newly added to the guidelines.

Importance of Awareness and Treatment for Diabetes in Influenza Vaccination Coverage of Diabetic Patients under 65 Years: A Population-Based Study

BackgroundInfluenza is a global public health problem causing considerable morbidity and mortality. Although vaccination is the most effective way to prevent infection, vaccination coverage is insufficient in people with chronic disease under 65 years, especially diabetes. The purpose of this study was to evaluate influenza vaccination coverage and identify factors associated with influenza vaccination in Korean diabetic adults under 65 years.MethodsData were obtained from 24,821 subjects in the Korea National Health and Nutrition Examination Survey (2014 to 2017). Socioeconomic, health-related, and diabetic factors were investigated for their relations with influenza vaccination in diabetic patients under 65 years using univariate and multivariate analyses.ResultsAmong 24,821 subjects, 1,185 were diabetic patients under 65 years and their influenza vaccination rate was 36.5%. Socioeconomic (older age, female gender, non-smoker, light alcohol drinker, lower educational level, and employed status), health-related factors (lower fasting glucose and glycosylated hemoglobin level, good self-perceived health status, more comorbidities, recent health screening, more outpatient visits, and diet therapy), and diabetic factors (more awareness and getting treated) were associated with influenza vaccination. In multivariate analysis, more awareness and getting treated for diabetes were associated with influenza vaccination in diabetic patients under 65 years (odds ratio, 1.496 and 1.413; 95% confidence interval, 1.022 to 2.188 and 1.018 to 2.054, respectively).ConclusionInfluenza vaccination rate was low in diabetic patients under 65 years, especially in those with unawareness and not getting treated for diabetes. Active screening and treatment for diabetes may be helpful to improve the influenza vaccination rate in these patients.

Revised Korean Cough Guidelines, 2020: Recommendations and Summary Statements / 결핵및호흡기질환

Cough is the most common respiratory symptom that can have various causes. It is a major clinical problem that can reduce a patient’s quality of life. Thus, clinical guidelines for the treatment of cough were established in 2014 by the cough guideline committee under the Korean Academy of Tuberculosis and Respiratory Diseases. From October 2018 to July 2020, cough guidelines were revised by members of the committee based on the first guidelines. The purpose of these guidelines is to help clinicians efficiently diagnose and treat patients with cough. This article highlights the recommendations and summary of the revised Korean cough guidelines. It includes a revised algorithm for the evaluation of acute, subacute, and chronic cough. For a chronic cough, upper airway cough syndrome (UACS), cough variant asthma (CVA), and gastroesophageal reflux disease (GERD) should be considered in differential diagnoses. If UACS is suspected, first-generation antihistamines and nasal decongestants can be used empirically. In cases with CVA, inhaled corticosteroids are recommended to improve cough. In patients with suspected chronic cough due to symptomatic GERD, proton pump inhibitors are recommended. Chronic bronchitis, bronchiectasis, bronchiolitis, lung cancer, aspiration, intake of angiotensin-converting enzyme inhibitor, intake of dipeptidyl peptidase-4 inhibitor, habitual cough, psychogenic cough, interstitial lung disease, environmental and occupational factors, tuberculosis, obstructive sleep apnea, peritoneal dialysis, and unexplained cough can also be considered as causes of a chronic cough. Chronic cough due to laryngeal dysfunction syndrome has been newly added to the guidelines.

Direct and Indirect Costs of Chronic Obstructive Pulmonary Disease in Korea / 결핵및호흡기질환

BACKGROUND: Understanding the burden of disease is important to establish cost-effective treatment strategies and to allocate healthcare resources appropriately. However, little reliable information is available regarding the overall economic burden imposed by chronic obstructive pulmonary disease (COPD) in Korea. METHODS: This study is a multicenter observational research on the COPD burden in Korea. Total COPD costs were comprised of three categories: direct medical, direct non-medical, and indirect costs. For direct medical costs, institutional investigation was performed at 13 medical facilities mainly based on the claims data. For direct non-medical and indirect costs, site-based surveys were administered to the COPD patients during routine visits. Total costs were estimated using the COPD population defined in the recent report. RESULTS: The estimated total costs were approximately 1,245 million US dollar (1,408 billion Korean won). Direct medical costs comprised approximately 20% of the total estimated costs. Of these, formal medical costs held more than 80%. As direct non-medical costs, nursing costs made up the largest percentage (39%) of the total estimated costs. Costs for COPD-related loss of productivity formed four fifths of indirect costs, and accounted for up to 33% of the total costs. CONCLUSION: This study shows for the first time the direct and indirect costs of COPD in Korea. The total costs were enormous, and the costs of nursing and lost productivity comprised approximately 70% of total costs. The results provide insight for an effective allocation of healthcare resources and to inform establishment of strategies to reduce national burden of COPD.

Factors Related to the Diagnostic Yield of Flexible Bronchoscopy without Guidance in Bronchoscopically Invisible Peripheral Lung Lesions / 결핵및호흡기질환

BACKGROUND: We aimed to analyze the factors predicting the diagnostic performance of flexible bronchoscopy without guidance in peripheral lung lesions that are endoscopically invisible. METHODS: This was a retrospective study conducted in St. Paul's Hospital, The Catholic University of Korea, between January 2007 and March 2013. We included all patients who received bronchoscopy during this period. The analyzed variables were age, sex, the etiology of the lesion, lesion size, distance from the pleura, and presence of the bronchus sign. We used multiple logistic regression analysis to identify the significant independent factors associated with diagnostic yield. RESULTS: We included 151 patients in this study. The overall diagnostic yield was 58.3%. The sensitivity was 43.2% for malignant disease and 78.1% for benign disease. The benign lung lesions (p<0.001), lesion size (p=0.015), presence of the exposed type of bronchus sign (p<0.001), and presence of cavitary lung lesions (p=0.005) were factors influencing the yield of flexible bronchoscopy by univariate analysis. In a multivariate logistic regression analysis, the exposed type of bronchus sign and benign lung lesions were independent predicting factors (odds ratio [OR]: 27.95; 95% confidence interval [CI], 7.56–103.32; p<0.001 and OR, 4.91; 95% CI, 1.76–13.72; p=0.002). CONCLUSION: The presence of the exposed type of bronchus sign and benign lung lesions are determining factors of the diagnostic yield in flexible bronchoscopy in evaluating peripheral lesions that are not endoscopically visible.

Chronic Refractory Cough / 대한내과학회지

Chronic refractory cough is defined as a cough that persists despite guideline based treatment. It is seen in 20-46% of patients presenting to specialist cough clinics and it has a substantial impact on quality of life and healthcare utilization. Several terms have been used to describe this condition, including the recently introduced term cough hypersensitivity syndrome. Key symptoms include a dry irritated cough localized around the laryngeal region. Symptoms are not restricted to cough and can include globus, dyspnea, and dysphonia. Chronic refractory cough has factors in common with laryngeal hypersensitivity syndromes and chronic pain syndromes, and these similarities help to shed light on the pathophysiology of the condition. Its pathophysiology includes cough reflex sensitivity, central sensitization, peripheral sensitization, and paradoxical vocal fold movement. Chronic refractory cough often occurs after a viral infection. The diagnosis is made once the main disease that causes chronic cough have been excluded (or treated) and cough remains refractory to medical treatment. Treatments include speech pathology interventions using techniques adapted from the treatment of hyperfunctional voice disorders, as well as the use of centrally acting neuromodulators such as gabapentin and pregabalin. Potential new treatments in development also show promise.

The Korean Cough Guideline: Recommendation and Summary Statement / 결핵및호흡기질환

Cough is one of the most common symptom of many respiratory diseases. The Korean Academy of Tuberculosis and Respiratory Diseases organized cough guideline committee and cough guideline was developed by this committee. The purpose of this guideline is to help clinicians to diagnose correctly and treat efficiently patients with cough. In this article, we have stated recommendation and summary of Korean cough guideline. We also provided algorithm for acute, subacute, and chronic cough. For chronic cough, upper airway cough syndrome (UACS), cough variant asthma (CVA), and gastroesophageal reflux disease (GERD) should be considered. If UACS is suspicious, first generation anti-histamine and nasal decongestant can be used empirically. In CVA, inhaled corticosteroid is recommended in order to improve cough. In GERD, proton pump inhibitor is recommended in order to improve cough. Chronic bronchitis, bronchiectasis, bronchiolitis, lung cancer, aspiration, angiotensin converting enzyme inhibitor, habit, psychogenic cough, interstitial lung disease, environmental and occupational factor, tuberculosis, obstructive sleep apnea, peritoneal dialysis, and idiopathic cough can be also considered as cause of chronic cough. Level of evidence for treatment is mostly low. Thus, in this guideline, many recommendations are based on expert opinion. Further study regarding treatment for cough is mandatory.

Efficacy of Team-Based Financial Incentives for Smoking Cessation in the Workplace

Worksite smoking cessation programs offer accessibility of the target population, availability of occupational health support, and the potential for peer pressure and peer support. The purpose of this study was to identify the efficacy of the financial incentives given to various teams in the workplace. St. Paul's Hospital's employees were enrolled. Each team of employees consisted of smoking participants and non-smoking fellow workers from the same department. The financial incentive of 50000 won (about $45) was rewarded to the team for each successful participant-not to individual members-after the first week and then after one month. If the smokers in the team remained abstinent for a longer time period, the team was given an incentive of 100000 won for each successful participant after 3 and 6 months. A total 28 smoking participants and 6 teams were enrolled. Self-reported abstinence rates validated by urinary cotinine test at 3, 6, and 12 months after the initial cessation were 61%, 54%, and 50%, respectively. Smokers with high nicotine dependence scores or those who began participation 1 month after enrollment initiation had a lower abstinence rate at 3 months, but not at 6 and 12 months. Participants who succeeded at smoking cessation at 12 months were more likely to be older and have a longer smoking duration history. The financial incentives given to teams could be promising and effective to improve long-term rates of smoking cessation. This approach could use peer pressure and peer support in the workplace over a longer period.

Identification of EGFR Mutations by Immunohistochemistry with EGFR Mutation-Specific Antibodies in Biopsy and Resection Specimens from Pulmonary Adenocarcinoma / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: Mutation-specific antibodies have recently been developed for identification of epidermal growth factor receptor (EGFR) mutations by immunohistochemistry (IHC). This study was designed to investigate whether the type of specimen (biopsy vs. resection) would make a difference in determining mutation status by IHC, and to evaluate whether biopsies are suitable for detection of mutant EGFR protein. MATERIALS AND METHODS: IHC was performed using mutation-specific antibodies for E746-A750 deletion (DEL) and L858R point mutation (L858R) in biopsies and tissue microarrays of resected tumors from 154 patients with pulmonary adenocarcinoma. Results were then compared with DNA sequencing data. RESULTS: Molecular-based assays detected EGFR mutations in 62 patients (40.3%), including 14 (9.1%) with DEL, and 31 (20.1%) with L858R. IHC with two mutation-specific antibodies showed a homogeneous staining pattern, and correctly identified EGFR mutation status in 89% (137/154). Overall (biopsy/resection) sensitivity, specificity, positive predictive value, and negative predictive value were 75.6% (78.3%/72.7%), 94.5% (90.9%/96.3%), 85% (78.3%/88.9%), and 90.4% (90.9%/89.7%), respectively. CONCLUSION: Our data showed that IHC using EGFR mutation-specific antibodies is useful for detection of EGFR mutations with high specificity and good sensitivity not only for resection specimens but also for biopsy materials. Therefore, IHC using EGFR mutation-specific antibodies may preclude a second biopsy procedure to obtain additional tissues for identification of EGFR mutations by molecular assays in biopsies from advanced cancer, particularly when tumor cells in the samples are limited.

A Case of Severe Pseudomembranous Tracheobronchitis Complicated by Co-infection of Influenza A (H1N1) and Staphylococcus aureus in an Immunocompetent Patient / 결핵및호흡기질환

Although influenza A (H1N1) virus leads to self-limiting illness, co-infection with bacteria may result in cases of severe respiratory failure due to inflammation and necrosis of intra-airway, as pseudomembranous tracheobronchitis. Pseudomembranous tracheobronchitis is usually developed in immunocompromised patients, but it can also occur in immunocompetent patients on a very rare basis. We report a case of pseudomembranous tracheobronchitis complicated by co-infection of inflenaza A and Staphylococcus aureus, causing acute respiratory failure in immunocompetent patients.

A Case of Pneumomediastinum and Parapneumonic Effusions Following Pharyngeal Perforation Caused by Shouting

Spontaneous pneumomediastinum is an uncommon disorder, and usually affects young men and has a benign course. Common triggers are asthma, the smoking of illicit drugs, the Valsalva maneuver, and respiratory infections. Most cases are usually due to alveolar rupture into the pulmonary interstitium caused by excess pressure. The air dissects to the hilum along the peribronchovascular sheaths and spreads into the mediastinum. However, pneumomediastinum following pharyngeal perforation is very rare, and has only been reported in relation to dental procedures, head and neck surgery, or trauma. We report a case of pneumomediastinum that developed in a 43-year-old patient with pharyngeal perforation after shouting. His course was complicated by mediastinitis and parapneumonic effusions.

Factors predictive of the failure of medical treatment in patients with pleural infection

BACKGROUND/AIMS: The clinical outcomes of some patients with pleural infection may be favorable with medical treatment alone, but in others, the disease progresses and requires additional surgical treatment. However, little is known about the factors affecting this difference. The aim of this study was to investigate the factors predictive of failure of medical treatment in patients with pleural infection. METHODS: A cohort of 127 consecutive patients who were admitted to the hospital with pleural infection was studied. Clinical manifestations and laboratory findings in patients in whom medical treatment succeeded or failed were reviewed. RESULTS: In univariate analysis, the significant factors associated with medical treatment outcome were age, smoking history, duration of chief complaint, serum albumin level, and pleural fluid glucose and lactate dehydrogenase levels (p < 0.05). Multivariate logistic regression analysis identified age and duration of chief complaint as independent predictive factors for failure of medical treatment, with odds ratios of 0.871 (p = 0.013) and 0.797 (p = 0.026), respectively. Receiver operating characteristic curve analysis determined cutoff values of 50.5 years for age and 4.5 days for duration of chief complaint. CONCLUSIONS: We demonstrated that a younger age < 50.5 years and shorter duration of chief complaint < 4.5 days were independent predictive factors for the failure of medical treatment in patients with pleural infection. This suggests their role as evaluative criteria in setting indications for the optimal treatment in patients with pleural infection. A larger, prospective study is required to confirm these findings.

Pulmonary Cryptococcosis Mimicking Primary Lung Cancer with Multiple Lung Metastases / 결핵및호흡기질환

Cryptococcosis is an invasive fungal infection, which is more common in immunocompromised patients. However, pulmonary cryptococcosis can occur in immunocompetent patients and should be considered on a differential diagnosis for nodular or mass-like lesions in chest radiograph. Recently, we experienced a patient with pulmonary cryptococcosis, successfully treated with oral fluconazole therapy. A 74-year-old female patient was referred for an evaluation of abnormal images, a large consolidative mass with multiple nodular consolidations and small nodules that mimics primary lung cancer with multiple lung to lung metastases. Computed tomography-guided lung biopsy confirmed the diagnosis of pulmonary cryptococcosis. The follow-up image taken after 4 months with oral fluconazole treatment showed marked improvement.

A Case of Tracheobronchial Aspergillosis Resolved Spontaneously in an Immunocompetent Host / 결핵및호흡기질환

A 47-year old man visited our hospital because of purulent sputum for 3 months. Chest X-ray showed destruction of both the upper lungs, and bronchoscopy revealed inflammatory change with whitish plaque on the left main bronchus through upper division of the left upper lobe. Tracheobronchial aspergillosis (TBA) was finally diagnosed as a result of histologic and microbiologic examination. However, he went abroad without medication before the diagnosis was made and visited again 10 months later. Follow-up bronchoscopy showed complete regression of the previously noted endobronchial lesion. We describe this case to consider the role of antifungal treatment in immunocompetent hosts, as well as to discuss a rare condition; TBA resolved spontaneously.

Three Cases of Cough Syncope in Lung Cancer Patients / 결핵및호흡기질환

Cough syncope is characterized by the loss of consciousness occurring after vigorous coughings. There are approximately 90 reported cases of cough syncope within the medical literature. Most cases involving middle aged, overweight and chronic bronchitic male smokers. Although many studies have been published in the medical literature, the mechanism and pathophysiology for cough syncope has not been well established. Cough syncope is treated by correcting the underlying cause when identified, or by avoiding conditions that may cause the cough syncope. In addition, cough suppression modalities can also be used. We herein report 3 cases of cough syncope presenting in lung cancer patients.

A Short-Term Effectiveness of Smoking Cessation Intervention in Outpatient Department of Pulmonology / 결핵및호흡기질환

BACKGROUND: There is very limited data present on smoking cessation rates in outpatient departments of pulmonology. In this study, we aimed to investigate the effectiveness of a brief smoking cessation intervention program in an outpatient department of pulmonology and identify predictors of smoking cessation failure. METHODS: After a brief recommendation of smoking cessation from pulmonologists, smokers willing to quit smoking were given individual counseling and supplement drugs. Fifty smokers were included in this study and baseline characteristics, smoking history and success rate were reviewed at 3 months. RESULTS: The mean age of the patients was 58.3+/-14.6 years and the total group of patients included 3 women. The rate of smoking cessation success was 74% at 3 months, and there were no differences in age, spirometric indexes and associated diseases between the smoking cessation success and failure group. The rate of supplement drug usage was not different in both groups either. However, body weight, mean number of cigarette usage per day and nicotine dependence scores in the failure group were significantly higher than in the success group. In multivariate analysis, body weight and mean number of cigarette usage per day were significant. Two smokers with a depressive disorder failed the smoking cessation. CONCLUSION: A smoking cessation intervention program in the outpatient department of pulmonology showed a favorable success rate. More intensive interventions are needed to unfavorable groups which include the obese and heavy smokers.

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 Radiolucent Foreign Body (Temporary Resin Bridge) Aspiration Accompanied by Inflammatory Polyps / 결핵및호흡기질환

This case demonstrates the rare occurrence of a radiolucent temporary resin bridge aspiration in adults while they are in a conscious and awaken state and the resultant formation of inflammatory polyps. Although no unique findings were noted in a chest x-ray, careful history taking accompanied by physical examinations can lead to clinical suspicion of foreign body aspiration in an earlier stage. Moreover, flexible bronchoscopy is a tool useful not only for the evaluation process but also for managing the aspirated foreign material.

Acute Respiratory Failure Associated with Cryptococcal Pneumonia and Disseminated Cryptococcosis in an AIDS Patient

A 36-year-old homosexual Mexican man was admitted to our hospital, with a 30-day history of fever and headache. Upon cerebrospinal fluid examination, the patient's white blood cell count was 1,580/L, total protein was 26 mg/dL, sugar was 17 mg/dL, and his intracranial pressure was 23 cmH2O. The patient was diagnosed with HIV (Human Immunodeficiency Virus) infection by serum Western blotting. Cryptococcus neoformans was isolated in cultures of the patient's blood and cerebrospinal fluids. Chest computerized tomography revealed diffuse reticulonodular infiltration and a ground-glass appearance in both perihilar regions, suggestive of either Pneumocystis carinii pneumonia or cryptococcal pneumonia. On the patient's 6th day in our hospital, bronchoalveolar lavage and transbronchial lung biopsy were conducted via bronchoscopy, and a pathologic examination of lung biopsy specimens revealed signs of cryptococcal pneumonia. This patient died on his 14th day in our hospital, as the result of acute respiratory failure, associated with cryptococcal pneumonia and disseminated cryptococcosis.