Hyouk-Soo Kwon

Epidemiologic and clinical features of anaphylaxis in Korea

BACKGROUND Little is known about the characteristics of anaphylaxis in Korea or even in Asia. OBJECTIVE To evaluate the incidence of anaphylaxis and the clinical features of patients with anaphylaxis in a Korean tertiary care hospital. METHODS We performed a retrospective review from January 1, 2000, through July 31, 2006, of 138 patients with anaphylaxis, including inpatients, outpatients, and emergency department visitors, in the Seoul National University Hospital. RESULTS Among 978,146 patients, 138 (0.014%) had anaphylaxis. Two cardiopulmonary resuscitations were performed and 1 death occurred. The total mortality rate of anaphylactic patients was 0.0001%. The causes of anaphylaxes were drug (35.3%), food (21.3%), food-dependent exercise-induced (13.2%), idiopathic (13.2%), insect stings (11.8%), exercise induced (2.9%), blood products (1.5%), and latex (0.7%). Radiocontrast media and buckwheat were the leading causes of drug and food anaphylaxis, respectively. The organs most frequently involved in the anaphylaxis were cutaneous (95.7%), cardiovascular (76.8%), and respiratory (74.6%). The most common manifestations were dyspnea (71.3%), urticaria (81.9%), and angioedema (69.4%). Three of 138 patients (2.2%) had biphasic reactions. CONCLUSIONS The incidence, mortality rate, and clinical features of Korean patients with anaphylaxis were similar to rates for patients from other countries, despite some differences in causative agents.

Metformin reduces airway inflammation and remodeling via activation of AMP-activated protein kinase.

Recent reports have suggested that metformin has anti-inflammatory and anti-tissue remodeling properties. We investigated the potential effect of metformin on airway inflammation and remodeling in asthma. The effect of metformin treatment on airway inflammation and pivotal characteristics of airway remodeling were examined in a murine model of chronic asthma generated by repetitive challenges with ovalbumin and fungal-associated allergenic protease. To investigate the underlying mechanism of metformin, oxidative stress levels and AMP-activated protein kinase (AMPK) activation were assessed. To further elucidate the role of AMPK, we examined the effect of 5-aminoimidazole-4-carboxamide-1-β-4-ribofuranoside (AICAR) as a specific activator of AMPK and employed AMPKα1-deficient mice as an asthma model. The role of metformin and AMPK in tissue fibrosis was evaluated using a bleomycin-induced acute lung injury model and in vitro experiments with cultured fibroblasts. Metformin suppressed eosinophilic inflammation and significantly reduced peribronchial fibrosis, smooth muscle layer thickness, and mucin secretion. Enhanced AMPK activation and decreased oxidative stress in lungs was found in metformin-treated asthmatic mice. Similar results were observed in the AICAR-treated group. In addition, the enhanced airway inflammation and fibrosis in heterozygous AMPKα1-deficient mice were induced by both allergen and bleomycin challenges. Fibronectin and collagen expression was diminished by metformin through AMPKα1 activation in cultured fibroblasts. Therefore metformin reduced both airway inflammation and remodeling at least partially through the induction of AMPK activation and decreased oxidative stress. These data provide insight into the beneficial role of metformin as a novel therapeutic drug for chronic asthma.

Identification of asthma clusters in two independent Korean adult asthma cohorts

Asthma is a heterogeneous airway disease with various clinical phenotypes. It is crucial to clearly identify clinical phenotypes to achieve better asthma management. We used cluster analysis to classify the clinical groups of 724 asthmatic patients from the Cohort for Reality and Evolution of Adult Asthma in Korea (COREA), and in 1843 subjects from another independent Korean asthma cohort of Soonchunhyang University Asthma Genome Research Centre (SCH) (Bucheon, Republic of Korea). Hierarchical cluster analysis was performed by Wards method, followed by &kgr;-means cluster analysis. Cluster analysis of the COREA cohort indicated four asthma subtypes: 1) smoking asthma; 2) severe obstructive asthma; 3) early-onset atopic asthma; and 4) late-onset mild asthma. An independent cluster analysis of the SCH cohort also indicated four clusters that were similar to the COREA clusters. Our results indicate that adult Korean asthma patients can be classified into four distinct clusters.

Characteristics of liver injury in drug-induced systemic hypersensitivity reactions

BACKGROUND The liver is the most commonly involved internal organ in drug-induced systemic hypersensitivity. However, data obtained from these patients have yet to be analyzed in depth with respect to liver injury. METHODS The medical records of 136 patients who developed delayed-type drug hypersensitivity were reviewed at a tertiary referral hospital. Culprit drugs, the pattern and degree of liver injury, and the effect of systemic corticosteroids were evaluated in the group of patients with drug-induced systemic hypersensitivity and liver dysfunction (aspartate aminotransferase or alanine aminotransferase ≥80 IU/L). Clinical characteristics of patients with drug-induced systemic hypersensitivity and liver injury were analyzed. RESULTS Among the 61 patients with drug-induced systemic hypersensitivity and liver dysfunction, the clinical phenotypes were drug reaction with eosinophilia and systemic symptoms (n = 29, 48%), Stevens-Johnson syndrome/toxic epidermal necrolysis (n = 11, 18%), and maculopapular rash (n = 17, 28%). Antibiotics (n = 27, 44%) were the most common cause of drug-induced systemic hypersensitivity with liver dysfunction. Whereas patients with Stevens-Johnson syndrome/toxic epidermal necrolysis had mild hepatocellular-type liver injury of relatively brief duration, those with drug reaction with eosinophilia and systemic symptoms/drug-induced hypersensitivity syndrome had more severe and prolonged hepatocellular injury in addition to moderate to severe cholestatic-type liver injury. The use of systemic corticosteroids did not significantly affect either recovery from liver injury or mortality. LIMITATIONS This study was retrospective and the number of subjects was small. CONCLUSION The results suggest that the severity, pattern, and duration of liver injury differ according to the drug-hypersensitivity phenotype. Further studies are needed to evaluate the role of systemic corticosteroids in drug-induced systemic hypersensitivity and liver injury.

Classification and implementation of asthma phenotypes in elderly patients

BACKGROUND No attempt has yet been made to classify asthma phenotypes in the elderly population. It is essential to clearly identify clinical phenotypes to achieve optimal treatment of elderly patients with asthma. OBJECTIVES To classify elderly patients with asthma by cluster analysis and developed a way to use the resulting cluster in practice. METHODS We applied k-means cluster to 872 elderly patients with asthma (aged ≥ 65 years) in a prospective, observational, and multicentered cohort. Acute asthma exacerbation data collected during the prospective follow-up of 2 years was used to evaluate clinical trajectories of these clusters. Subsequently, a decision-tree algorithm was developed to facilitate implementation of these classifications. RESULTS Four clusters of elderly patients with asthma were identified: (1) long symptom duration and marked airway obstruction, (2) female dominance and normal lung function, (3) smoking male dominance and reduced lung function, and (4) high body mass index and borderline lung function. Cluster grouping was strongly predictive of time to first acute asthma exacerbation (log-rank P = .01). The developed decision-tree algorithm included 2 variables (percentage of predicted forced expiratory volume in 1 second and smoking pack-years), and its efficiency in proper classification was confirmed in the secondary cohort of elderly patients with asthma. CONCLUSIONS We defined 4 elderly asthma phenotypic clusters with distinct probabilities of future acute exacerbation of asthma. Our simplified decision-tree algorithm can be easily administered in practice to better understand elderly asthma and to identify an exacerbation-prone subgroup of elderly patients with asthma.

Effect of pregnancy in asthma on health care use and perinatal outcomes

BACKGROUND It is generally known that pregnancy in asthmatic patients increases the risk of asthma exacerbations and poor perinatal outcomes. However, the effect of pregnancy in asthmatic patients on health care use is not known well. In addition, its effect on perinatal outcomes is still controversial because of study limitations caused by ethical issues. National Health Insurance claim data are an ideal resource for studying real-world health care use patterns of asthma. OBJECTIVE We sought to evaluate the effect of pregnancy on asthma in terms of asthma-related health care use and prescription patterns in concert with the effect of asthma exacerbations on adverse pregnancy outcomes. METHODS Among all asthmatic patients in the Korean National Health Insurance claim database from January 2009 to December 2013, pregnant women who delivered in 2011 with pre-existing asthma were enrolled. Analyses included asthma-related health care use and prescription patterns compared between pregnant asthmatic women and nonpregnant female asthmatic control subjects, as well as within the pregnant subjects from before pregnancy throughout postpartum periods. In addition, the association between asthma exacerbation during pregnancy and adverse pregnancy outcomes was assessed. RESULTS A total of 3,357 pregnant asthmatic patients were compared with 50,355 nonpregnant asthmatic patients, and 10,311 pregnant patients were included to determine the effect of asthma exacerbations on adverse pregnancy outcome in the study. Pregnant asthmatic patients underwent more asthma-related hospitalizations (1.3% vs 0.8%, P = .005) but had significantly fewer outpatient visits and prescriptions for most asthma medications than nonpregnant asthmatic patients. The proportion of patients ever hospitalized gradually increased throughout pregnancy (first trimester, 0.2%; second trimester, 0.5%; and third trimester, 0.7%; P = .018). The prevalence of asthma exacerbation during pregnancy was 5.3%, and the patients who had acute exacerbation during pregnancy had significantly higher asthma-related health care use in terms of hospitalization, intensive care unit admission, and emergency department and outpatient visits within 1 year before delivery than those who had not. However, asthma exacerbation during pregnancy was not significantly related to adverse perinatal outcomes, except for cesarean section (27.1% vs 18.9%, P < .001). All exacerbations were managed with systemic corticosteroids, and the patients who ever experienced acute exacerbations maintained asthma medications, including inhaled corticosteroid-based inhalers, throughout the pregnancy period. CONCLUSION Pregnancy profoundly affects asthma-related health care use but to a different degree depending on whether the patient experienced an exacerbation. Asthma exacerbation during pregnancy is not associated with adverse pregnancy outcomes while managed appropriately with systemic corticosteroids. However, further studies are needed to clarify the effect of asthma control on perinatal outcome and delivery method.

Surveillance of contrast-media-induced hypersensitivity reactions using signals from an electronic medical recording system

BACKGROUND Contrast-media (CM) hypersensitivity is a well-known adverse drug reaction. Surveillance of adverse drug reactions usually depends on spontaneous reports. However, the rate of spontaneous reports is low. Recent progress in information technology enables the electronic search on signals of adverse drug reactions from electronic medical recording (EMR) systems. OBJECTIVES To analyze the incidence and clinical characteristics of CM hypersensitivity using an EMR-based surveillance system. METHODS The surveillance system used signals from standardized terms within the international classification of nursing practice terms that can indicate symptoms of CM hypersensitivity and from the order codes for procedures that used contrast media, antihistamine, and epinephrine. The search strategy was validated by allergists comparing the electronic search strategy versus manually reviewing medical charts over one month. The main study covered for one year period. RESULTS Detection rate of the electronic search method was 0.9% (7/759), while that of the manual search method was 0.8% (6/759). EMR-based electronic search method was highly efficient: reduced the charts that needed to be reviewed by 96% (28/759). The sensitivity of electronic screening was 66.7%, specificity was 99.6%, and the negative predictive value was 99.7%. CM hypersensitivity reactions were noted in 266 among 12,483 cases (2.1%). Urticaria was the most frequent symptom (74.4%). CT was the most frequent procedure (3.6%) that induced CM hypersensitivity. CONCLUSION A surveillance system using EMR may be a useful tool in the study of drug hypersensitivity epidemiology and may be used in an adverse drug reaction alarm system and as a clinical, decision making support system.

Multilocus analysis of atopy in Korean children using multifactor-dimensionality reduction

Background: Atopy is considered to be a complex genetic trait and does not follow a simple mendelian pattern of inheritance. It is now well recognised that gene–gene interactions are important in complex genetic disease. Aim: To analyse the influence of gene–gene interactions in the development of atopy. Methods: A total of 2055 ethnically identical participants aged 10–18 years living in rural areas on Jeju Island, Korea, were randomly recruited. Atopy was defined as a positive skin prick test response to one or more common inhalant allergens. Gene–gene interactions among 12 polymorphic loci were analysed in the seven candidate genes of atopy using the multidimensionality-reduction method. Results: A significant interaction was found between V297I in the gene coding vascular endothelial growth factor receptor 2 (KDR) and −308G→A in the gene coding tumour necrosis factor (TNF)α on the risk of atopy, with a cross-validation consistency of 10 out of 10 and a prediction error of 35.9% (p = 0.001). Conventional logistic regression also revealed significant interactions between KDR and TNF for atopy. Individuals with the variant allele of −308G→A in TNF (GA or AA) and V297I in KDR (VI or II) had a significantly higher risk of atopy (OR 2.23; 95% CI 1.48 to 3.57). Conclusion:KDR and TNF may synergistically influence the development of atopy through gene–gene interaction in Korean children and adolescents.

The Effectiveness of Automatic Recommending System for Premedication in Reducing Recurrent Radiocontrast Media Hypersensitivity Reactions

Background Non-ionic radiocontrast media (RCM) is rarely associated with hypersensitivity reactions. Premedication of patients who reacted previously to RCM with systemic corticosteroids and/or antihistamines can help reduce recurrent hypersensitivity reactions. However, premedication is still not prescribed in many cases for various reasons. This study aimed to determine the effectiveness of our novel RCM hypersensitivity surveillance and automatic recommending system for premedication. Methods and Results Hospitalized patients with a history of RCM hypersensitivity were identified in an electronic medical record system that included a mandatory reporting system for past adverse drug reactions. In 2009, a novel automatic prescription system was added that classified index RCM reactions by severity and dispensed appropriate corticosteroid and/or antihistamine pretreatment prior to new RCM exposures. The data from 12 months under the previous system and 12 months under the current system were compared. The two systems had similar overall premedication rates (91% and 95%) but the current system was associated with a significantly higher corticosteroid premedication rate (65% vs. 14%), which significantly reduced the breakthrough reaction rate (6.7% vs. 15.2%). The current system was also associated with increased corticosteroid and antihistamine premedication of patients with a mild index reaction (61% vs. 7%) and a reduction in their breakthrough reaction rate (6% vs. 15%). Conclusions Premedication with corticosteroid and/or antihistamine, which was increased by our novel automatic prescription system, significantly reduced breakthrough reactions in patients with a history of RCM hypersensitivity.

Clinical Significance of Asthma Clusters by Longitudinal Analysis in Korean Asthma Cohort

Background We have previously identified four distinct groups of asthma patients in Korean cohorts using cluster analysis: (A) smoking asthma, (B) severe obstructive asthma, (C) early-onset atopic asthma, and (D) late-onset mild asthma. Methods and Results A longitudinal analysis of each cluster in a Korean adult asthma cohort was performed to investigate the clinical significance of asthma clusters over 12 months. Cluster A showed relatively high asthma control test (ACT) scores but relatively low FEV1 scores, despite a high percentage of systemic corticosteroid use. Cluster B had the lowest mean FEV1, ACT, and the quality of life questionnaire for adult Korean asthmatics (QLQAKA) scores throughout the year, even though the percentage of systemic corticosteroid use was the highest among the four clusters. Cluster C was ranked second in terms of FEV1, with the second lowest percentage of systemic corticosteroid use, and showed a marked improvement in subjective symptoms over time. Cluster D consistently showed the highest FEV1, the lowest systemic corticosteroid use, and had high ACT and QLQAKA scores. Conclusion Our asthma clusters had clinical significance with consistency among clusters over 12 months. These distinctive phenotypes may be useful in classifying asthma in real practice.