Machine Learning-Based Discrimination of Cardiovascular Outcomes in Patients With Hypertrophic Cardiomyopathy.

Background: Current risk stratification strategies for patients with hypertrophic cardiomyopathy (HCM) are limited to traditional methodologies. Objectives: The authors aimed to establish machine learning (ML)-based models to discriminate major cardiovascular events in patients with HCM. Methods: We enrolled consecutive HCM patients from 2 tertiary referral centers and used 25 clinical and echocardiographic features to discriminate major adverse cardiovascular events (MACE), including all-cause death, admission for heart failure (HF-adm), and stroke. The best model was selected for each outcome using the area under the receiver operating characteristic curve (AUROC) with 20-fold cross-validation. After testing in the external validation cohort, the relative importance of features in discriminating each outcome was determined using the SHapley Additive exPlanations (SHAP) method. Results: In total, 2,111 patients with HCM (age 61.4 ± 13.6 years; 67.6% men) were analyzed. During the median 4.0 years of follow-up, MACE occurred in 341 patients (16.2%). Among the 4 ML models, the logistic regression model achieved the best AUROC of 0.800 (95% CI: 0.760-0.841) for MACE, 0.789 (95% CI: 0.736-0.841) for all-cause death, 0.798 (95% CI: 0.736-0.860) for HF-adm, and 0.807 (95% CI: 0.754-0.859) for stroke. The discriminant ability of the logistic regression model remained excellent when applied to the external validation cohort for MACE (AUROC = 0.768), all-cause death (AUROC = 0.750), and HF-adm (AUROC = 0.806). The SHAP analysis identified left atrial diameter and hypertension as important variables for all outcomes of interest. Conclusions: The proposed ML models incorporating various phenotypes from patients with HCM accurately discriminated adverse cardiovascular events and provided variables with high importance for each outcome.

Sacubitril/valsartan and the risk of incident dementia in heart failure: a nationwide propensity-matched cohort study.

BACKGROUND: Sacubitril acts to inhibit neprilysin and as neprilysin is involved in amyloid-beta degradation in the central nervous system, and there is concern that sacubitril/valsartan may increase the risk of dementia. We aimed to compare the risk of incident dementia associated with sacubitril/valsartan and angiotensin II receptor blockers (ARBs). METHODS: Patients with heart failure with reduced ejection fraction treated with either sacubitril/valsartan or ARB, identified from the Korean National Health Insurance Service database, were matched in a 1:2 ratio using propensity scores (6789 on sacubitril/valsartan and 13,578 on ARBs) and followed up for incident dementia. RESULTS: During a mean follow-up of 2.5 years, 526 (2.6%) patients were newly diagnosed with dementia: Alzheimer dementia in 282, vascular dementia in 8, and other dementia in 236. There was no significant difference in the risk of overall dementia (hazard ratio [HR] 0.84, 95% confidence interval [CI] 0.70-1.01), Alzheimer dementia (HR 0.85, 95% CI 0.67-1.10), vascular dementia (HR 0.98, 95% CI 0.23-4.11), and all other dementias (HR 0.81, 95% CI 0.62-1.07) between sacubitril/valsartan users and ARB users. These results were consistent regardless of initial sacubitril/valsartan dose and subgroups including old age, previous mild cognitive impairment, previous stroke, and concomitant antiplatelet or anticoagulation. Sensitivity analysis with a 1-year lag period for dementia assessment confirmed the main analysis. Meanwhile, risk of incident stroke was lower in sacubitril/valsartan users compared to ARBs users. CONCLUSIONS: In a nationwide propensity-matched cohort of patients with heart failure, sacubitril/valsartan was not associated with an increased risk of incident dementia compared to ARBs. Sacubitril/valsartan and the risk of incident dementia in heart failure. ARB, angiotensin II receptor blocker; ARNI, angiotensin receptor neprilysin inhibitor.

Association between exercise and risk of fractures in new-onset type 2 diabetes: a retrospective cohort study.

In this population-based retrospective cohort study, exercising before and after the diagnosis of type 2 diabetes was significantly associated with lower risk of fractures. This result suggested that exercising might be effective in reducing fracture risk. PURPOSE: Patients with diabetes have a significantly higher risk of fractures. We aimed to investigate the association between exercise and fracture risk in new-onset type 2 diabetes. METHODS: This retrospective cohort study using the Korean National Health Insurance Service database included 170,148 patients with new-onset type 2 diabetes who underwent two cycles of health checkup between 2009-2012 and 2011-2014. The patients were classified into four groups (non-exercising, newly exercising, previously exercising, and continuously exercising) and followed up until the date of fracture, death, or December 31, 2018. Hip fractures, vertebral fractures, and any fractures were defined using diagnostic codes. RESULTS: The proportions of non-exercising, newly exercising, previously exercising, and continuously exercising patients were 65.1%, 15.7%, 10.9%, and 8.3%, respectively. Continuously exercising patients showed the lowest risk for fractures, followed by newly exercising patients using the non-exercising group as a reference. The adjusted hazard ratios (95% confidence intervals) for hip fracture, vertebral fracture, and any fracture were 0.69 (0.50-0.94), 0.73 (0.63-0.84), and 0.90 (0.83-0.97), respectively, in the continuously exercising group and 0.76 (0.61-0.95), 0.85 (0.76-0.94), and 0.93 (0.88-0.98) in the newly exercising group. The risk was lower in patients who lost less than 5% of their body weight than in those who lost 5% or more. CONCLUSION: Exercising was associated with lower risk of fractures in newly diagnosed diabetes. However, exercise accompanied by excessive weight loss may not have a significant association with a lower risk of fractures.

Impact of coronary artery revascularization on long-term outcome in hypertrophic cardiomyopathy patients: a nationwide population-based cohort study.

Limited data are available on the long-term outcomes in patients with hypertrophic cardiomyopathy (HCM) patients with significant coronary artery disease (CAD) requiring revascularization. We investigated the risk of cardiovascular outcomes in HCM patients who underwent coronary revascularization compared to the control group without HCM. HCM patients aged ≥ 20 years were enrolled from the Korean National Health Insurance Database. Information on the diagnosis and previous medical history was obtained from the claims data. Cardiovascular outcomes were identified during 8-year after coronary revascularization in HCM patients (HCM group) and matched controls without HCM (non-HCM control group). A total of 431 patients in the HCM group and 1968 in the non-HCM control group were analyzed. The risk of all-cause death, cardiovascular death, sudden cardiac death (SCD), ischemic stroke, and hospitalization due to heart failure was significantly higher in the HCM group than in the non-HCM group, with prominent risk increase of cardiovascular death (adjusted hazard ratio [HR] 2.27, 95% confidence interval [CI] 1.63-3.15, P < 0.001) and ischemic stroke (adjusted HR 2.38, 95% CI 1.55-3.64, P < 0.001). Beyond 1-year after revascularization, the HCM group still had a significantly higher risk of cardiovascular death, SCD, and ventricular fibrillation/tachycardia compared to the non-HCM group. Mortality and major cardiovascular outcomes occurred more frequently in HCM patients with significant CAD requiring revascularization, compared to the matched non-HCM control group. Active and regular surveillance for concomitant risk factors and relevant intervention are warranted in HCM patients at increased risk for CAD.

KAAACI Allergic Rhinitis Guidelines: Part 2. Update in Non-pharmacological Management.

Allergic rhinitis is the most common chronic disease worldwide. Various upper airway symptoms lower quality of life, and due to the recurrent symptoms, multiple treatments are usually attempted rather than one definitive treatment. There are alternatives to medical (medication-based) and non-medical treatments. A guideline is needed to understand allergic rhinitis and develop an appropriate treatment plan. We have developed guidelines for medical treatment based on previous reports. The current guidelines herein are associated with the "KAAACI Evidence-Based Guidelines for Allergic Rhinitis in Korea, Part 1: Update in pharmacotherapy" in which we aimed to provide evidence-based recommendations for the medical treatment of allergic rhinitis. Part 2 focuses on non-pharmacological management, including allergen-specific immunotherapy, subcutaneous or sublingual immunotherapy, nasal saline irrigation, environmental management strategies, companion animal management, and nasal turbinate surgery. The evidence to support the treatment efficacy, safety, and selection has been systematically reviewed. However, larger controlled studies are needed to elevate the level of evidence to select rational non-medical therapeutic options for patients with allergic rhinitis.

The effect of metabolic dysfunction-associated fatty liver disease and diabetic kidney disease on the risk of hospitalization of heart failure in type 2 diabetes: a retrospective cohort study.

BACKGROUND: Diabetes mellitus is a major risk factor for heart failure. A recent consensus statement recommended annual cardiac biomarker testing (e.g. natriuretic peptide or high-sensitivity cardiac troponin) for all patients with diabetes. We aimed to identify patients at a higher risk of hospitalization for heart failure among patients with type 2 diabetes to prioritize those who would require screening. METHODS: Overall, 1,189,113 patients who underwent two medical health checkup cycles (2009-2012 and 2011-2014) and had stable diabetic kidney disease (DKD) phenotype in the Korean National Health Insurance Service database were included in this study. After excluding those with concurrent proteinuria (PU) and reduced estimated glomerular filtration rate, three groups (no-DKD, PU+DKD, and PU-DKD) were identified. A fatty liver index of ≥ 60 was defined as metabolic dysfunction-associated fatty liver disease (MAFLD). Patients were followed up until December 2018 or until outcomes developed. The Cox proportional hazard model was used to compare the risk of hospitalization for heart failure across groups. RESULTS: During an average of 6.6 years of follow-up, 5781 patients developed hospitalization for heart failure. After adjusting for covariates, the risk of hospitalization for heart failure was highest in the PU+DKD group [HR 3.12, 95% CI (2.75-3.55)], followed by the PU-DKD group [HR 1.85, 95% CI (1.73-1.99)] using the no-DKD group as the reference category. The risk of hospitalization for heart failure was comparable regardless of MAFLD status in patients who already had DKD. However, in the no-DKD group, the risk of hospitalization for heart failure was 1.4 times higher in patients with MAFLD than in those without [HR 1.41, 95% CI (1.31-1.52)]. CONCLUSIONS: In lines with the international consensus statement, we suggest that annual cardiac biomarker testing should be conducted at least in patients with DKD and/or MAFLD.

Safety and effectiveness of anticoagulation with non-vitamin K antagonist oral anticoagulants and warfarin in patients on tuberculosis treatment.

Anti-tuberculosis treatment can cause significant drug-drug interaction and interfere with effective anticoagulation. However, there is a lack of evidence and conflicting data on the optimal oral anticoagulation in patients treated for tuberculosis. We investigated the safety and effectiveness of anticoagulation with non-vitamin K antagonist oral anticoagulants (NOACs) and warfarin in patients on anti-tuberculosis treatment. Patients on concomitant oral anticoagulation and anti-tuberculosis treatment including rifampin were identified from the Korean nationwide healthcare database. Subjects were censored at discontinuation of either anticoagulation or rifampin. The outcomes of interest were major bleeding, death, and ischemic stroke. A total 2090 patients (1153 on warfarin, 937 on NOAC) were included. NOAC users, compared to warfarin users, were older, had a lower prevalence of hypertension, heart failure, ischemic stroke, and aspirin use and a higher prevalence of cancer, with no significant differences in CHA2DS2-VASc or HAS-BLED scores. There were 18 major bleeding events, 106 deaths, and 50 stroke events during a mean follow-up of 2.9 months. After multivariable adjustment, the use of NOAC was associated with a lower risk of incident ischemic stroke (HR 0.51, 95% CI 0.27-0.94), while there was no significant difference in risk for major bleeding or death compared with warfarin. These results suggest that NOACs have better effectiveness for stroke prevention and similar safety compared with warfarin in patients on concomitant anti-tuberculosis treatment. This is the first study assessing the safety and effectiveness of NOACs compared to warfarin in this clinical scenario.

KAAACI Allergic Rhinitis Guidelines: Part 1. Update in Pharmacotherapy.

The prevalence of allergic rhinitis (AR) and the socioeconomic burden associated with the medical cost and quality of life (QOL) of AR have progressively increased. Therefore, practical guidelines for the appropriate management of AR need to be developed based on scientific evidence while considering the real-world environment, values, and preferences of patients and physicians. The Korean Academy of Asthma, Allergy and Clinical Immunology revised clinical guidelines of AR to address key clinical questions of the management of AR. Part 1 of the revised guideline covers the pharmacological management of patients with AR in Korea. Through a meta-analysis and systematic review, we made 4 recommendations for AR pharmacotherapy, including intranasal corticosteroid (INCS)/intranasal antihistamine (INAH) combination therapy, oral antihistamine/INCS combination therapy, leukotriene receptor antagonist treatment in AR patients with asthma, and prophylactic treatment for patients with pollen-induced AR. However, all recommendations are conditional because of the low or very low evidence of certainty. Well-designed and strictly executed randomized controlled trials are needed to measure and report appropriate outcomes.

Clinical characteristics of pediatric patients infected with SARS-CoV-2 versus common human coronaviruses: a national multicenter study.

BACKGROUND: Human coronaviruses (HCoV) cause mild upper respiratory infections; however, in 2019, a novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), emerged, causing an acute respiratory disease pandemic. Coronaviruses exhibit marked epidemiological and clinical differences. PURPOSE: This study compared the clinical, laboratory, and radiographic findings of children infected with SARS-CoV-2 versus HCoV. METHODS: SARS-CoV-2 data were obtained from the Korea Disease Control and Prevention Agency (KDCA) registry and 4 dedicated coronavirus disease 2019 (COVID-19) hospitals. Medical records of children admitted with a single HCoV infection from January 2015 to March 2020 were collected from 10 secondary/tertiary hospitals. Clinical data included age, sex, underlying disease, symptoms, test results, imaging findings, treatment, and length of hospital stay. RESULTS: We compared the clinical characteristics of children infected with HCoV (n=475) to those of children infected with SARS-CoV-2 (272 from KDCA, 218 from COVID-19 hospitals). HCoV patients were younger than KDCA patients (older than 9 years:3.6% vs. 75.7%; P<0.001) and patients at COVID-19 hospitals (2.0±2.9 vs 11.3±5.3; P<0.001). Patients with SARS-CoV-2 infection had a lower rate of fever (26.6% vs. 66.7%; P<0.001) and fewer respiratory symptoms than those with HCoV infection. Clinical severity, as determined by oxygen therapy and medication usage, was worse in children with HCoV infection. Children and adolescents with SARS-CoV-2 had less severe symptoms. CONCLUSION: Children and adolescents with COVID-19 had a milder clinical course and less severe disease than those with HCoV in terms of symptoms at admission, examination findings, and laboratory and radiology results.

Assessment of variables associated with prolonged admission duration in children with Mycoplasma pneumoniae pneumonia.

INTRODUCTION: Macrolide-resistant Mycoplasma pneumoniae (MRMP) has become prevalent in children. This study investigated the clinical and laboratory variables of MRMP and macrolide-sensitive M. pneumoniae (MSMP) and identified factors associated with prolonged hospital admission in children. METHODS: A prospective multicenter study was conducted in 1063 children <18 years old in July 2018-June 2020. The 454 had a positive M. pneumoniae polymerase chain reaction assay. RESULTS: Most subjects had MRMP (78.4%), and all mutated strains had the A2063G transition. We defined MRMP* (n = 285) as MRMP pneumonia requiring admission and MSMP* (n = 72) as MSMP pneumonia requiring admission. Patients with MRMP pneumonia were older, more likely to have segmental/lobar pneumonia, and had more febrile days than those with MSMP pneumonia. C-reactive protein (CRP), lactate dehydrogenase (LDH), and percentage neutrophils were more strongly associated with MRMP* than MSMP* groups. Percentage neutrophils, CRP, and alanine aminotransferase significantly changed between admission and follow-up measurements in patients with MRMP* (P < 0.05). The duration of admission positively correlated with the number of febrile days after initiation of antibiotic medication and laboratory variables (white blood cell count, CRP, and aspartate aminotransferase [AST]) (P < 0.05). Random forest analysis indicated that the number of febrile days after initiation of antibiotic medication, AST, and percentage neutrophils at admission was over five. CONCLUSIONS: This study indicated that children with M. pneumoniae pneumonia with a higher number of febrile days after initiation of antibiotic medication, AST, and percentage neutrophils at admission were more likely to have prolonged admission duration.

Association Between Changes in Alcohol Consumption and Cancer Risk.

Importance: Although numerous studies have shown an association between alcohol consumption and cancer, how changes in drinking behavior increase or decrease the incidence of cancer is not well understood. Objective: To investigate the association between the reduction, cessation, or increase of alcohol consumption and the development of alcohol-related cancers and all cancers. Design, Setting, and Participants: This population-based cohort study analyzed adult beneficiaries in the Korean National Health Insurance Service. Participants (aged ≥40 years) included those who underwent a national health screening in both 2009 and 2011 and had available data on their drinking status. Data were analyzed from April 16 to July 6, 2020. Exposures: Alcohol consumption level, which was self-reported by participants in health screening questionnaires, was categorized into none (0 g/d), mild (<15 g/d), moderate (15-29.9 g/d), and heavy (≥30 g/d) drinking. Based on changes in alcohol consumption level from 2009 to 2011, participants were categorized into the following groups: nondrinker, sustainer, increaser, quitter, and reducer. Main Outcomes and Measures: The primary outcome was newly diagnosed alcohol-related cancers (including cancers of the head and neck, esophagus, colorectum, liver, larynx, and female breast), and the secondary outcome was all newly diagnosed cancers (except for thyroid cancer). Results: Among the 4 513 746 participants (mean [SD] age, 53.6 [9.6] years; 2 324 172 [51.5%] men), the incidence rate of cancer was 7.7 per 1000 person-years during a median (IQR) follow-up of 6.4 (6.1-6.6) years. Compared with the sustainer groups at each drinking level, the increaser groups had a higher risk of alcohol-related cancers and all cancers. The increased alcohol-related cancer incidence was associated with dose; those who changed from nondrinking to mild (adjusted hazard ratio [aHR], 1.03; 95% CI, 1.00-1.06), moderate (aHR, 1.10; 95% CI, 1.02-1.18), or heavy (aHR, 1.34; 95% CI, 1.23-1.45) drinking levels had an associated higher risk than those who did not drink. Those with mild drinking levels who quit drinking had a lower risk of alcohol-related cancer (aHR, 0.96; 95% CI, 0.92-0.99) than those who sustained their drinking levels. Those with moderate (aHR, 1.07; 95% CI, 1.03-1.12) or heavy (aHR, 1.07; 95% CI, 1.02-1.12) drinking levels who quit drinking had a higher all cancer incidence than those who sustained their levels, but when quitting was sustained, this increase in risk disappeared. Compared with sustained heavy drinking, reduced heavy drinking levels to moderate levels (alcohol-related cancer: aHR, 0.91 [95% CI, 0.86-0.97]; all cancers: aHR, 0.96 [95% CI, 0.92-0.99]) or mild levels (alcohol-related cancer: aHR, 0.92 [95% CI, 0.86-0.98]; all cancers: aHR, 0.92 [95% CI, 0.89-0.96]) were associated with decreased cancer risk. Conclusions and Relevance: Results of this study showed that increased alcohol consumption was associated with higher risks for alcohol-related and all cancers, whereas sustained quitting and reduced drinking were associated with lower risks of alcohol-related and all cancers. Alcohol cessation and reduction should be reinforced for the prevention of cancer.

Food allergy in early childhood increases the risk of oral allergy syndrome in schoolchildren: A birth cohort study.

BACKGROUND: The level of pollen in Korea has increased over recent decades. Research suggests that oral allergy syndrome (OAS) may be more frequent in childhood than previously recognized. We aimed to investigate the prevalence and characteristics of OAS in children aged 6-10 years from a general-population-based birth cohort. METHODS: We analyzed 930 children from the cohort for childhood origin of asthma and allergic diseases (COCOA). Allergic diseases were diagnosed annually by pediatric allergists. The skin prick tests were performed with 14 common inhalant allergens and four food allergens for the general population of children aged 3 and 7 years. RESULTS: Of the 930 eligible children, 44 (4.7%) aged 6-10 years were diagnosed with OAS. The mean age at onset was 6.74 years. OAS prevalence was 7.2% among children with allergic rhinitis (AR) and 19.1% among those with pollinosis, depending on comorbidity. OAS was more prevalent in schoolchildren with atopic dermatitis, food allergy, and sensitization to food allergens and grass pollen in early childhood. In schoolchildren with AR, only a history of food allergy until the age of 3 years increased the risk of OAS (aOR 2.971, 95% CI: 1.159-7.615). CONCLUSION: Food allergy and food sensitization in early childhood were associated with OAS in schoolchildren with AR. Further study is required to elucidate the mechanism by which food allergy in early childhood affects the development of OAS.

Analysis of national surveillance of respiratory pathogens for community-acquired pneumonia in children and adolescents.

BACKGROUND: Respiratory infections among children, particularly community-acquired pneumonia (CAP), is a major disease with a high frequency among outpatient and inpatient visits. The causes of CAP vary depending on individual susceptibility, the epidemiological characteristics of the community, and the season. We performed this study to establish a nationwide surveillance network system and identify the causative agents for CAP and antibiotic resistance in Korean children with CAP. METHODS: The monitoring network was composed of 28 secondary and tertiary medical institutions. Upper and lower respiratory samples were assayed using a culture or polymerase chain reaction (PCR) from August 2018 to May 2020. RESULTS: A total of 1023 cases were registered in patients with CAP, and PCR of atypical pneumonia pathogens revealed 422 cases of M. pneumoniae (41.3%). Respiratory viruses showed a positivity rate of 65.7% by multiplex PCR test, and human rhinovirus was the most common virus, with 312 cases (30.5%). Two hundred sixty four cases (25.8%) were isolated by culture, including 131 cases of S. aureus (12.8%), 92 cases of S. pneumoniae (9%), and 20 cases of H. influenzae (2%). The cultured, isolated bacteria may be colonized pathogen. The proportion of co-detection was 49.2%. The rate of antibiotic resistance showed similar results as previous reports. CONCLUSIONS: This study will identify the pathogens that cause respiratory infections and analyze the current status of antibiotic resistance to provide scientific evidence for management policies of domestic respiratory infections. Additionally, in preparation for new epidemics, including COVID-19, monitoring respiratory infections in children and adolescents has become more important, and research on this topic should be continuously conducted in the future.

Impact of diabetes mellitus on the outcomes of subjects with hypertrophic cardiomyopathy: A nationwide cohort study.

AIMS: Diabetes mellitus (DM) often coexists in elderly hypertrophic cardiomyopathy (HCM) patients; however, its impact on clinical outcomes is unclear. METHODS: We compared clinical outcomes according to the presence of DM in a nationwide HCM cohort. RESULTS: In 9,883 HCM subjects (mean age 58.5 ± 13.1, men 71.7%), 1,327 (13.4%) had DM. During follow-up (mean 5.9 ± 2.5 years), end-stage renal disease (ESRD) progression, coronary events (myocardial infarction, coronary revascularization), heart failure (HF), cardiovascular mortality, and all-cause mortality occurred in 80 (0.8%), 365 (3.7%), 1,558 (15.8%), 354 (3.6%), and 877 (8.9%) subjects, respectively. DM HCM subjects had significantly higher risks of ESRD progression (HR 3.49, 95% CI 2.20-5.54) and HF (HR 1.15, 95% CI 1.01-1.32) compared to non-DM HCM subjects, independent of age, sex, ischemic heart disease, atrial fibrillation, and other comorbidities. There was a tendency for greater risk of ESRD progression, HF, and all-cause death in subjects with more advanced stage of DM (p-for-trend < 0.05 for all). Insulin-treated DM was associated with the highest risk. CONCLUSIONS: DM HCM subjects have higher risk of ESRD progression and HF. Considering the extended life expectancy of HCM and increasing number of elderly HCM subjects, active surveillance and management of DM-related outcomes should be highlighted.

Clinical Characteristics of Macrolide-Refractory Mycoplasma pneumoniae Pneumonia in Korean Children: A Multicenter Retrospective Study.

Mycoplasma pneumoniae is a major causative pathogen of community-acquired pneumonia in children, and the treatment of choice is macrolides. There is an increasing trend in reports of refractory clinical responses despite macrolide treatment due to the emergence of macrolide-resistant M. pneumoniae. Early discrimination of macrolide-refractory M. pneumoniae pneumonia (MrMP) from macrolide-sensitive M. pneumoniae pneumonia (MSMP) is vital; however, testing for macrolide susceptibility at the time of admission is not feasible. This study aimed to identify the characteristics of MrMP in Korean children, in comparison with those of MSMP. In this multicenter study, board-certified pediatric pulmonologists at 22 tertiary hospitals reviewed the medical records from 2010 to 2015 of 5294 children who were hospitalized with M. pneumoniae pneumonia and administered macrolides as the initial treatment. One-way analysis of variance and the Kruskal-Wallis test were used to compare differences between groups. Of 5294 patients (mean age, 5.6 years) included in this analysis, 240 (4.5%), 925 (17.5%), and 4129 (78.0%) had MrMP, macrolide-less effective M. pneumoniae pneumonia, and MSMP, respectively. Compared with the MSMP group, the MrMP group had a longer fever duration, overall (13.0 days) and after macrolide use (8.0 days). A higher proportion of MrMP patients had respiratory distress, pleural effusion, and lobar pneumonia. The mean aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, and C-reactive protein levels were the highest in the MrMP group, along with higher incidences of extrapulmonary manifestations and atelectasis (during and post infection). Pre-existing conditions were present in 17.4% (n = 725/4159) of patients, with asthma being the most common (n = 334/4811, 6.9%). This study verified that MrMP patients show more severe initial radiographic findings and clinical courses than MSMP patients. MrMP should be promptly managed by agents other than macrolides.

Impact of body mass index on development of nontuberculous mycobacterial pulmonary disease.

The incidence and prevalence of nontuberculous mycobacterial pulmonary disease (NTM-PD) have been increasing worldwide. The risk of NTM-PD may be higher in undernourished populations. In this study, we tried to elucidate the impact of body mass index (BMI) and its change on development of NTM-PD.We performed a retrospective cohort study including South Koreans aged >40 years who underwent biennial National Health Insurance System (NHIS) health check-ups in both 2005 and 2009 or 2006 and 2010. We monitored eligible individuals from the study initiation date (NHIS health check-up date in 2009 or 2010) until the diagnosis of NTM-PD or until December 31, 2017. Enroled individuals were classified based on BMI at initiation date. By calculating hazard ratios, we compared NTM-PD incidence per 100 000 person-years by BMI group and by BMI change.A total of 5 670 229 individuals were included in the final analysis. Compared with the BMI <18.5 kg·m-2 group, the incidence of NTM-PD gradually decreased with increased BMI (adjusted hazard ratio 0.38, 95% confidence interval (CI) 0.35-0.42 for BMI 18.5-22.9; 0.17, 95% CI 0.15-0.19 for BMI 23-24.9; 0.1, 95% CI 0.09-0.11 for BMI 25-29.9; and 0.1, 95% CI 0.07-0.13 for BMI ≥30). A BMI decrease of ≥1 kg·m-2 over 4 years increased the incidence of NTM-PD (adjusted hazard ratio 1.08, 95% CI 1.01-1.16) whereas a BMI increase of ≥1 kg·m-2 decreased the incidence of NTM-PD (adjusted hazard ratio 0.77, 95% CI 0.71-0.83).In conclusion, BMI was inversely related to development of NTM-PD and weight loss increased the risk of NTM-PD.

Clinical impact of atrial fibrillation in a nationwide cohort of hypertrophic cardiomyopathy patients.

BACKGROUND: The clinical implications of atrial fibrillation (AF) in hypertrophic cardiomyopathy (HCM) patients are incompletely characterized. We investigated the impact of AF on stroke and mortality, assessed the performance of the CHA2DS2-VASc score, and explored the predictors of stroke in HCM patients. METHODS: A nationwide cohort of HCM patients (n=8,349, mean age 60.7) identified from 2010 to 2015 from the Korean National Health Insurance database were followed up for occurrence of ischemic stroke or all-cause death. RESULTS: During a mean follow-up of 2.5 years, the incidence rate of stroke was 2.69 and 5.87, and mortality rate was 2.06 and 4.44 per 100 person-years in non-AF and AF patients, respectively. AF was independently associated with a 60% and 50% increased risk for stroke and all-cause mortality, respectively. The AF-associated increase in risk of stroke was more prominent in HCM patients with no or few risk factors. The CHA2DS2-VASc score showed poor discrimination of stroke risk in HCM patients with AF, mostly due to the high incidence of stroke in patients with scores of 0 or 1. Traditional risk factors were not always associated with stroke in HCM patients with AF; age, heart failure, high blood pressure and GGT were the strongest predictors of stroke in this population. HCM patients without AF also showed increased incidence of stroke at CHA2DS2-VASc ≥1. CONCLUSIONS: AF was independently associated with increased risks for stroke and all-cause mortality in patients with HCM. The CHA2DS2-VASc score showed poor discrimination of stroke risk in HCM patients with AF.

Annual and seasonal patterns in etiologies of pediatric community-acquired pneumonia due to respiratory viruses and Mycoplasma pneumoniae requiring hospitalization in South Korea.

BACKGROUND: Community-acquired pneumonia (CAP) is one of the leading worldwide causes of childhood morbidity and mortality. Its disease burden varies by age and etiology and is time dependent. We aimed to investigate the annual and seasonal patterns in etiologies of pediatric CAP requiring hospitalization. METHODS: We conducted a retrospective study in 30,994 children (aged 0-18 years) with CAP between 2010 and 2015 at 23 nationwide hospitals in South Korea. Mycoplasma pneumoniae (MP) pneumonia was clinically classified as macrolide-sensitive MP, macrolide-less effective MP (MLEP), and macrolide-refractory MP (MRMP) based on fever duration after initiation of macrolide treatment, regardless of the results of in vitro macrolide sensitivity tests. RESULTS: MP and respiratory syncytial virus (RSV) were the two most commonly identified pathogens of CAP. With the two epidemics of MP pneumonia (2011 and 2015), the rates of clinical MLEP and MRMP pneumonia showed increasing trends of 36.4% of the total MP pneumonia. In children < 2 years of age, RSV (34.0%) was the most common cause of CAP, followed by MP (9.4%); however, MP was the most common cause of CAP in children aged 2-18 years of age (45.3%). Systemic corticosteroid was most commonly administered for MP pneumonia. The rate of hospitalization in intensive care units was the highest for RSV pneumonia, and ventilator care was most commonly needed in cases of adenovirus pneumonia. CONCLUSIONS: The present study provides fundamental data to establish public health policies to decrease the disease burden due to CAP and improve pediatric health.

Clinical Manifestations and Risk Factors of Anaphylaxis in Pollen-Food Allergy Syndrome.

PURPOSE: Many studies have reported that pollen-food allergy syndrome (PFAS) can cause anaphylaxis. No comprehensive investigations into anaphylaxis in PFAS have been conducted, however. In this study, we investigated the clinical manifestations and risk factors for anaphylaxis in PFAS in Korean patients with pollinosis. MATERIALS AND METHODS: Data were obtained from a nationwide cross-sectional study that previously reported on PFAS in Korean patients with pollinosis. Data from 273 patients with PFAS were collected, including demographics, list of culprit fruits and vegetables, and clinical manifestations of food allergy. We analyzed 27 anaphylaxis patients and compared them with patients with PFAS with oropharyngeal symptoms only (n=130). RESULTS: The most common cause of anaphylaxis in PFAS was peanut (33.3%), apple (22.2%), walnut (22.2%), pine nut (18.5%), peach (14.8%), and ginseng (14.8%). Anaphylaxis was significantly associated with the strength of sensitization to alder, hazel, willow, poplar, timothy, and ragweed (p<0.05, respectively). Multivariable analysis revealed that the presence of atopic dermatitis [odds ratio (OR), 3.58; 95% confidence interval (CI), 1.25-10.23; p=0.017]; sensitization to hazel (OR, 5.27; 95% CI, 1.79-15.53; p=0.003), timothy (OR, 11.8; 95% CI, 2.70-51.64; p=0.001), or ragweed (OR, 3.18; 95% CI, 1.03-9.87; p=0.045); and the number of culprit foods (OR, 1.25; 95% CI, 1.15-1.37; p<0.001) were related to the development of anaphylaxis in PFAS. CONCLUSION: The most common culprit foods causing anaphylaxis in PFAS were peanut and apple. The presence of atopic dermatitis; sensitization to hazel, timothy, or ragweed; and a greater number of culprit foods were risk factors for anaphylaxis in PFAS.