M. S. Park

The Responses of Multiple Cytokines Following Incubation of Whole Blood from TB Patients, Latently Infected Individuals and Controls with the TB Antigens ESAT‐6, CFP‐10 and TB7.7

The development of clinically relevant biomarkers is important for diagnosing latent tuberculosis infection (LTBI) and active tuberculosis (TB) and predicting their prognoses. This study examined whether the responses of multiple cytokines can be used as a biomarker to distinguish the TB infection status and mycobacterial load. We analysed the responses of multiple cytokines (IFN‐γ, IL‐2, IL‐10, IL‐13, IL‐17 and TNF‐α) in the supernatant from the QuantiFERON‐TB Gold In‐Tube assay following stimulation of whole blood from the TB group (n = 32), LTBI group (n = 19) and healthy controls (n = 30) with TB antigens (ESAT‐6, CFP‐10 and TB7.7). The median responses of IFN‐γ, IL‐2, IL‐10 and IL‐13 were higher in the LTBI and active TB groups than in the non‐TB control group (IFN‐γ, P < 0.001; IL‐2, P < 0.001; IL‐10, P = 0.012; IL‐13, P < 0.001). The median IL‐2/IFN‐γ ratio of the LTBI group was higher than that of the active TB group (P = 0.014) and differed significantly between patients with LTBI, patients with smear‐negative TB and patients with smear‐positive TB (P = 0.027). This difference was especially evident between the patients with LTBI and patients with smear‐positive TB (P = 0.047). In conclusion, IFN‐γ, IL‐2, IL‐10 and IL‐13 can serve as biomarkers for distinguishing TB infection. In addition, the IL‐2/IFN‐γ ratio appears to be a biomarker for diagnosing LTBI and may be useful as a prognostic factor and for evaluating treatment responses.

Association between vitamin D deficiency and tuberculosis in a Korean population.

BACKGROUND Several in vitro studies have been conducted regarding the immunomodulatory and mycobactericidal roles of vitamin D in tuberculous infection. However, discrepancies exist among epidemiological studies. We compared vitamin D deficiency between patients with tuberculosis (TB) and healthy control subjects and identified risk factors for vitamin D deficiency. METHOD This was an age- and sex-matched case-control analysis of 94 TB cohort and 282 Korean national survey participants. RESULTS The median baseline 25-hydroxyvitamin D (25[OH]D) level in the TB group (9.86 ng/ml, IQR 7.19-14.15) was lower than in controls (16.03 ng/ml, IQR 12.38-20.30, P < 0.001). The prevalence of severe vitamin D deficiency was higher in patients with TB (51.1%) than in controls (8.2%, P = 0.001). The median 25(OH)D level increased from 11.40 ng/ml (IQR 7.85-15.73) to 13.18 ng/ml (IQR 10.60-19.71) after treatment completion (P = 0.037). On multivariate analysis, presence of TB and history of TB were independently associated with severe vitamin D deficiency. CONCLUSION Patients with TB had a higher prevalence of vitamin D deficiency than control subjects in a Korean population. The median 25(OH)D level increased after TB treatment. Further studies are needed to establish a causal relationship.

Chronic obstructive pulmonary disease and metabolic syndrome: a nationwide survey in Korea.

SETTING Systemic inflammation has been suggested to be involved in the pathogenesis of chronic obstructive pulmonary disease (COPD) and metabolic syndrome. However, the association between these two conditions is not fully understood. OBJECTIVE To evaluate the relationship between COPD and metabolic syndrome. DESIGN Among subjects aged ≥40 years from the 2001 Korean National Health and Nutrition Examination Survey, 1215 subjects with two or more acceptable spirometry measurements and complete anthropometric/laboratory examinations were analysed. RESULTS A total of 133 subjects (11%, 100 men and 33 women) were newly diagnosed with COPD (forced expiratory volume in 1 second/forced vital capacity ≤ 70%). The prevalence of metabolic syndrome, based on the National Cholesterol Education Program Adult Treatment Panel III, was significantly higher in COPD subjects compared with non-COPD subjects in both sexes (33.0% vs. 22.2% in men and 48.5% vs. 29.6% in women). In men, the risk of COPD was higher in subjects with metabolic syndrome than in those without (OR 2.03, 95%CI 1.08-3.80), after adjusting for potential confounders. There was a borderline significant association between COPD and abdominal obesity among the individual component of metabolic syndrome (OR 1.95, 95%CI 0.93-4.11). CONCLUSION In the Republic of Korea, metabolic syndrome was associated with COPD in men.

Validation of a scoring tool to predict drug-resistant pathogens in hospitalised pneumonia patients.

BACKGROUND Health care-associated pneumonia (HCAP) affects a heterogeneous group of patients in frequent contact with health care systems. However, HCAP criteria poorly predict infection with drug-resistant (DR) pathogens. OBJECTIVE To validate our previously reported risk-scoring model (predictive of DR pathogen infection) in patients admitted to hospital with pneumonia. DESIGN We evaluated 580 patients admitted with culture-positive bacterial pneumonia. We identified risk factors, evaluated the risk-scoring models capacity to predict infection by DR pathogens and compared the models diagnostic accuracy with that of current HCAP criteria. RESULTS DR pathogens were observed in 227/580 patients (39.1%). Of 269 HCAP patients, 153 (56.9%) were infected with DR pathogens. Overtreatment was more common in HCAP than in community-acquired pneumonia (58.7% vs. 41.2%, P < 0.001). Recent hospitalisation, admission from a long-term care facility, recent antibiotic treatment and tube feeding were independently associated with DR pathogens. For pathogen prediction, the risk-scoring model showed better diagnostic accuracy than HCAP criteria (area under receiver operating-characteristic curve = 0.723 vs. 0.673, P < 0.001). CONCLUSION According to current HCAP criteria, half of the HCAP patients were treated unnecessarily with broad-spectrum antibiotics. Risk scoring by stratifying risk factors could improve the identification of patients likely to be infected with DR pathogens.

Body mass index and fat free mass index in obstructive lung disease in Korea.

OBJECTIVE To investigate the relationship between body mass index (BMI), fat free mass index (FFMI) and obstructive lung disease in Korea. DESIGN Based on a large population-based, nationwide survey conducted in Korea, 822 subjects with airway obstruction and the same number of healthy control subjects were selected. Spirometry and dual-energy X-ray absorptiometry were used for analysis. RESULTS Subjects with airway obstruction had a lower mean BMI and FFMI than the control group (23.6 vs. 23.9 kg/m(2) for BMI, P = 0.015 and 17.2 vs. 17.5 kg/m(2) for FFMI, P = 0.013); the BMI (P < 0.001) and FFMI (P < 0.001) values decreased significantly in subjects with severe airway obstruction. The proportion of subjects who were underweight or who had a low FFMI was significantly higher in the severe airway obstruction group (P < 0.001). The decrease in FFMI was more prominent in the lower extremities, followed by the upper extremities and the trunk. Subjects who were underweight had significantly lower one-second forced expiratory volume (FEV1; P = 0.001) and FEV1/forced vital capacity values (P < 0.001). CONCLUSION We suggest that lower BMI and FFMI are associated with degree of airway obstruction and that the assessment of BMI and body composition is necessary in patients with severe airway obstruction.

Pre-transplant risk factors for tuberculosis after kidney transplant in an intermediate burden area.

OBJECTIVE To examine pre-transplant risk factors for the development of post-kidney transplant tuberculosis (TB) in an intermediate TB burden country, as this is important for early detection and prophylaxis to prevent post-transplant TB. DESIGN A retrospective, longitudinal cohort study of 1097 kidney transplant patients was performed at the Severance Hospital, Seoul, South Korea, between January 2000 and March 2010. The standardised incidence ratio (SIR) of post-transplant TB compared to the general population was calculated and pre-transplant risk factors were analysed. RESULTS Among the 1097 kidney transplant patients, 2.1% (23/1097) developed post-transplant TB, with an incidence of 445.2 cases per 100,000 patients per year. The SIR of TB in kidney transplant patients compared with the general population was 4.26 (95%CI 2.6-6.45). A positive tuberculin skin test (TST; RR 3.54, 95%CI 1.13-11.11, P = 0.03) and previously healed TB on chest radiograph (CXR; RR 8.71, 95%CI 1.00-75.84, P = 0.05) were significant pre-transplant risk factors for post-transplant TB on multivariate analysis. CONCLUSION The incidence of TB in kidney transplant patients was higher than in the general population. Positive TST results and previously healed TB lesions visible on pre-transplant CXR were significant pre-transplant risk factors for post-kidney transplant TB.

Chronic obstructive lung disease―related health care utilisation in Korean adults with obstructive lung disease

OBJECTIVES The numbers of nationwide epidemiological surveys about chronic obstructive pulmonary disease (COPD) prevalence and prospective cohort studies for health care utilisation are limited. We investigated COPD-related health care utilisation in adults with obstructive lung disease in the second Korean National Health and Nutritional Survey (KNHANES II) in 2001 using Korean national medical insurance claim data. METHODS Among people aged >40 years, obstructive lung disease (OLD) is defined according to Global Initiative for Chronic Obstructive Lung Disease criteria. Data from a total of 1942 subjects were linked with Korean national medical insurance claims data, and we investigated their COPD-related out-patient visits from 2002 to 2005. RESULTS Among the 1942 subjects, 256 (13.2%) had airflow obstruction. COPD-related out-patient visits were reported for 8.2% of patients without airway obstruction, 18.1% of those with mild airway obstruction, and 33.9% of those with moderate to very severe airway obstruction. Multivariate analysis revealed that previous COPD diagnosis by a physician (OR 2.54; P = 0.02) and lower socio-economic status (OR 0.45; P = 0.02) were independent predictors of COPD-related out-patient visits in subjects with OLD. CONCLUSIONS Of the subjects with airway obstruction, those with poor financial status utilised COPD-related health care services less frequently, and those previously diagnosed as having COPD by a physician utilised the services more frequently.