Hyung Koo Kang

Systemic White Blood Cell Count as a Biomarker Associated with Severity of Chronic Obstructive Lung Disease

Background Chronic obstructive pulmonary disease (COPD), is a chronic inflammatory disorder. We evaluated whether white blood cell (WBC) count, is associated with the severity of COPD, independent of other inflammatory conditions, such as metabolic syndrome. Methods The WBC counts were compared between 1227 COPD patients and 8679 non-COPD adults older than 40. The relationships between the WBC count, lung function, and symptoms score in COPD patients, were determined, using general linear regression analyses. Results The WBC count was negatively associated with forced vital capacity (FVC, L), FVC (% predicted), forced expiry volume in one second (FEV1, L), and FEV1 (% predicted) in COPD patients. Additionally, the WBC count was independently associated with the quality of life measure, by EQ5D-index score. However, this relationship between WBC count, and disease severity, was not significant in current smokers, because of the confounding effect of smoking, on the WBC count. Conclusion The WBC count is associated with current smoking status and COPD severity, and a risk factor for poor lung function, and quality of life, especially in non-currently smoking COPD patients. The WBC count can be used, as an easily measurable COPD biomarker.

COPD assessment test score and serum C-reactive protein level in stable COPD patients

Background An eight-item questionnaire of the COPD assessment test (CAT) is widely used to quantify the impact of COPD on the patient’s health status. C-reactive protein (CRP) is associated with disease severity and adverse health outcomes of patients with COPD. This study aimed to evaluate the relationship between CAT score and serum CRP levels in stable COPD patients. Methods We evaluated the medical records of 226 patients with CAT and serum CRP measured within a week at Samsung Medical Center between October 2013 and October 2015. Results Serum CRP levels had a significantly positive relationship with CAT score (Spearman’s r=0.20, P=0.003). Patients with elevated serum CRP levels (>0.3 mg/dL) were significantly more likely to have CAT scores of ≥14. The adjusted odds ratio for elevated serum CRP levels in total CAT score was 1.06 (95% confidence interval, 1.02–1.09). Among CAT components, cough (adjusted P=0.005), phlegm (adjusted P=0.001), breathlessness going up hills/stairs (adjusted P=0.005), low confidence leaving home (adjusted P=0.002), and feeling low in energy (adjusted P=0.019) were independently associated with elevated serum CRP levels. Conclusion In stable COPD patients, serum CRP levels were independently associated with total CAT score and CAT components related to respiratory symptoms, confidence leaving home, and energy.

Relationship Between Forced Vital Capacity and Framingham Cardiovascular Risk Score Beyond the Presence of Metabolic Syndrome: The Fourth Korea National Health and Nutrition Examination Survey.

AbstractImpaired lung function is a risk factor for cardiovascular (CV) events. However, it has not been well established whether FVC reduction even within normal range is associated with cardiovascular disease (CVD) risk and whether reduced FVC is an independent relationship of CVD irrespective of metabolic syndrome. Thus, we aimed to explore the relationship between FVC and CV-event risk using the FRS beyond the presence of metabolic syndrome or abdominal obesity in a representative Korean population based on data from the nationwide Korea National Health and Nutrition Examination Survey (KNHANES IV).The study population included 9688 subjects ≥ 30 years of age with no previous diagnosis of CVD and obstructive lung disease. Using a logistic regression model and area under the curve (AUC) analysis, we evaluated the relationship between FVC quintiles and CV-event risk using the Framingham Risk Score (FRS; ≥ 10% or ≥ 20%). In addition, we examined the effect of FVC on CV-event risk based on the presence of metabolic syndrome (MetS) and abdominal obesity.After adjusting for covariates, comparison of subjects in the lowest FVC (% pred) quintile (Q1) with those in the highest quintile (Q5) yielded an odds ratio (OR) of 2.27 (95% CI, 1.91–2.71) for intermediate and high risk, and 2.89 (95% CI, 2.31–3.61) for high risk. The ORs for cardiovascular risk using FRS also increased irrespective of the presence of abdominal obesity and MetS without significant interaction. Furthermore, the addition of FVC status to MetS status and abdominal obesity status significantly increased the AUC of the model predicting CV-event risk (P < 0.001 and P < 0.001).Our study demonstrates that FVC is inversely associated with 10-year CV-event risk, irrespective of MetS and abdominal obesity in the general population without obstructive lung disease. Furthermore, the addition of FVC to MetS or abdominal obesity increased prediction of CVD event risks, implying a potential role of FVC to predict CV events.

Airflow limitation severity and post-operative pulmonary complications following extra-pulmonary surgery in COPD patients

The association between airflow limitation severity and post‐operative pulmonary complications (PPCs) among COPD patients undergoing extra‐pulmonary surgery is unknown. We evaluated the association between forced expiratory volume in 1 s (FEV1 ) and PPC in COPD patients undergoing extra‐pulmonary surgery.

Clinical significance of differentiating post‐intubation and post‐tracheostomy tracheal stenosis

Post‐intubation tracheal stenosis (PITS) and post‐tracheostomy tracheal stenosis (PTTS) are serious complications in mechanically ventilated patients. Although the aetiologies and mechanisms of PITS and PTTS are quite different, little is known about the clinical impact of differentiating one from the other.

Clinical significance of smear positivity for acid-fast bacilli after ≥5 months of treatment in patients with drug-susceptible pulmonary tuberculosis.

Abstract Patients with pulmonary tuberculosis (TB) with acid-fast bacilli (AFB)-positive sputum smear at 5 months or later during treatment are considered to be cases of treatment failure according to World Health Organization guidelines. This study evaluated the proportion, clinical characteristics, and significance of positive sputum smears after ≥5 months of standard treatment in patients with drug-susceptible pulmonary TB. This was a retrospective cohort study of 1611 patients with culture-confirmed drug-susceptible pulmonary TB who received standard anti-TB treatment from January 2009 to February 2014. Forty-one patients (2.5%) who were smear-positive after ≥5 months of treatment and 123 age- and sex-matched control patients were evaluated. Among the 41 smear-positive patients, culture of the sputum specimens yielded Mycobacterium tuberculosis (MTB) in 1 patient (2.4%), nontuberculous mycobacteria (NTM) in 7 (17.1%), and no growth in the remaining 33 patients (80.5%). Treatment was successfully completed in 40 patients (97.6%) with prolongation of the continuation phase regimens without change to second-line anti-TB treatment. In patients with smear positivity after ≥5 months of treatment compared with controls, cavitation on chest radiographs (53.7% vs. 25.2%, P = 0.001), bilateral involvement (51.2% vs. 30.1%, P = 0.01) and combined pleural effusion (26.8% vs. 10.6%, P = 0.01) were found more frequently at the time of treatment initiation, and paradoxical response occurred more commonly (19.5% vs. 3.3%, P = 0.002) during treatment. Smear-positive sputum after ≥5 months of standard anti-TB treatment was mainly because of nonviable MTB bacilli or NTM in patients with drug-susceptible pulmonary TB. AFB smear alone should not be used to assess treatment failure and careful examination of microbiologic status, including culture and drug susceptibility testing, is needed before making changes to retreatment regimens or empirical second-line anti-TB regimens in these patients.

The Utility of Endobronchial Ultrasound-guided Transbronchial Needle Aspiration in Patients with Small-cell Lung Cancer

Objective Most small-cell lung cancers (SCLCs) are located within the central aspect of the chest and manifest as a mediastinal or hilar lymphadenopathy. Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) makes it possible to perform mediastinal and hilar nodal examinations. The purpose of this study was to evaluate the performance of EBUS-TBNA in the diagnosis of SCLC. Methods The diagnostic performances of EBUS-TBNA and/or transesophageal bronchoscopic ultrasound-guided fine-needle aspiration (EUS-FNA-B/E) were calculated using the standard definitions. Patients The study consisted of a retrospective review of the medical records for all patients with histologically proven SCLC who previously underwent EBUS-TBNA and/or EUS-FNA-B/E from May 2009 to September 2014. Results The analysis was based on 161 patients and 299 aspirated specimens. The patient group included 144 males (89%); the median age was 66 years. EBUS-TBNA and/or EUS-FNA-B/E were performed in 239 mediastinal nodes, 39 hilar/interlobar nodes, and 21 lung parenchymal lesions. The median short diameter of the biopsied lesions was 17 mm. The overall sensitivity, specificity, negative predictive value, positive predictive value, and accuracy of EBUS-TBNA and/or EUS-FNA-B/E on a per-person basis were 97.4%, 100%, 60%, 100%, and 97.5%, respectively. The corresponding values on a per-lesion basis were 91.8%, 100%, 73.0%, 100%, and 93.3%, respectively. There were no serious complications related to EBUS-TBNA. Conclusion In our series of patients with SCLC, EBUS-TBNA had an excellent diagnostic yield in the evaluation of mediastinal, hilar and lung parenchymal lesions. Thus, EBUS-TBNA could be a useful and safe diagnostic method with which to evaluate patients with SCLC.

The Use of Lung Ultrasound in a Surgical Intensive Care Unit

Background Pulmonary complications including pneumonia and pulmonary edema frequently develop in critically ill surgical patients. Lung ultrasound (LUS) is increasingly used as a powerful diagnostic tool for pulmonary complications. The purpose of this study was to report how LUS is used in a surgical intensive care unit (ICU). Methods This study retrospectively reviewed the medical records of 67 patients who underwent LUS in surgical ICU between May 2016 and December 2016. Results The indication for LUS included hypoxemia (n = 44, 65.7%), abnormal chest radiographs without hypoxemia (n = 17, 25.4%), fever without both hypoxemia and abnormal chest radiographs (n = 4, 6.0%), and difficult weaning (n = 2, 3.0%). Among 67 patients, 55 patients were diagnosed with pulmonary edema (n = 27, 41.8%), pneumonia (n = 20, 29.9%), diffuse interstitial pattern with anterior consolidation (n = 6, 10.9%), pneumothorax with effusion (n = 1, 1.5%), and diaphragm dysfunction (n = 1, 1.5%), respectively, via LUS. LUS results did not indicate lung complications for 12 patients. Based on the location of space opacification on the chest radiographs, among 45 patients with bilateral abnormality and normal findings, three (6.7%) and two (4.4%) patients were finally diagnosed with pneumonia and atelectasis, respectively. Furthermore, among 34 patients with unilateral abnormality and normal findings, two patients (5.9%) were finally diagnosed with pulmonary edema. There were 27 patients who were initially diagnosed with pulmonary edema via LUS. This diagnosis was later confirmed by other tests. There were 20 patients who were initially diagnosed with pneumonia via LUS. Among them, 16 and 4 patients were finally diagnosed with pneumonia and atelectasis, respectively. Conclusions LUS is useful to detect pulmonary complications including pulmonary edema and pneumonia in surgically ill patients.

Hand grip strength in patients with chronic obstructive pulmonary disease

Purpose Hand grip strength (HGS) is a simple way of predicting the risk of cardiovascular disease and all-cause mortality in the general population. However, the practical significance of grip strength in patients with COPD is uncertain. The aim of this study was to compare HGS between subjects with and without COPD and to evaluate its clinical relevance in patients with COPD by using a national survey. Methods Data were collected from the Korean National Health and Nutrition Examination Survey. The study included 421 adults with COPD and 2,542 controls who completed questionnaires, spirometry, and a HGS test. HGS was compared between subjects with and without COPD, and the association between grip strength, lung function, and quality of life (QoL) was evaluated. Results The mean HGS was 33.3±9.1 kg in the COPD group and 29.9±9.5 kg in the non-COPD group; adjusted HGS was 30.9±0.33 kg and 30.9±0.11 kg, respectively (P=0.99). HGS was not related to forced vital capacity (β=0.04, P=0.70) or forced expiratory volume in 1 second (β=0.11, P=0.24) in multivariable analysis. HGS was independently associated with the EQ-5D index, but the relationship was stronger in the COPD group (β=0.30, P<0.001) than in the non-COPD group (β=0.21, P<0.001). The results were similar for each component of the EQ-5D, including mobility (β=−0.25, P<0.001), daily activity (β=−0.19, P=0.01), pain/discomfort (β=−0.32, P<0.001), and anxiety/depression (β=−0.16, P=0.01). Conclusion HGS was not different between subjects with and without COPD, but was associated with QoL – including mobility, daily activity, pain/discomfort, and anxiety/depression – in patients with COPD. The HGS test could be used as a marker of QoL in patients with COPD and could assist risk stratification in clinical practice.

Clinical Utility of Additional Measurement of Total Lung Capacity in Diagnosing Obstructive Lung Disease in Subjects With Restrictive Pattern of Spirometry

BACKGROUND: Total lung capacity (TLC), forced expiratory flow between 25 and 75% (FEF25-75%), peak expiratory flow (PEF), or post-bronchodilator volume response is recommended to detect obstructive abnormalities in the lung. The present study was performed to evaluate the usefulness of these pulmonary function test (PFT) parameters to diagnose obstructive lung disease in subjects with a restrictive pattern of spirometry. METHODS: A retrospective study was conducted in 64 subjects with a restrictive pattern of spirometry (normal FEV1/FVC and low FVC) out of 3,030 patients who underwent all pre- and post-bronchodilator spirometry and lung volume measurement between April 2008 and December 2010. After subjects were clinically classified into those with obstructive lung disease, restrictive lung disease, and mixed lung disease, the agreements between the clinical diagnosis and PFT classification according to TLC, FEF25-75%, PEF, and post-bronchodilator response criteria were compared. RESULTS: Of 64 subjects, 18 (28.1%) were classified with obstructive lung disease, 39 (60.9%) had restrictive lung disease, 1 (1.6%) had mixed lung disease, and 6 (9.4%) had no clinical lung disease. Among the 58 subjects with clinical lung disease, 22 (37.9%), 37 (63.8%), 33 (56.9%), and 3 (5.2%) were classified as having obstructive pattern based on TLC, FEF25-75%, PEF, and post-bronchodilator response criteria, respectively. The kappa coefficients for the agreement between the clinical classification and PFT classification using TLC, FEF25-75%, PEF, and post-bronchodilator response criteria in 58 subjects were 0.59, 0.18, 0.17, and < 0.01, respectively. CONCLUSIONS: The additional measurement of TLC is more useful than FEF25-75%, PEF, and post-bronchodilator response for diagnosis of obstructive lung disease in subjects with a restrictive pattern of spirometry, when obstructive lung disease is clinically suspected.