Healthcare use and prescription patterns associated with adult asthma in Korea: analysis of the NHI claims database

Short-acting β2-agonist prescriptions in patients with asthma: findings from the South Korean cohort of SABINA III

BACKGROUND/AIMS

Despite short-acting β2-agonist (SABA) overuse being associated with poor asthma outcomes, data on SABA use in South Korea is scarce. Herein, we describe prescription patterns of SABA and other asthma medications in patients from the South Korean cohort of the SABA use IN Asthma (SABINA) III study.

METHODS

This study included patients with asthma aged ≥ 12 years, who had ≥ 3 consultations with the same healthcare provider, and medical records containing data for ≥ 12 months prior to the study visit. Patients were classified by investigator-defined asthma severity (per 2017 Global Initiative for Asthma recommendations) and practice type (primary or specialist care). Data on disease characteristics, asthma treatments, and clinical outcomes in the 12 months before the study visit were collected using electronic case report forms.

RESULTS

Data from 476 patients (mean age, 55.4 years; female, 63.0%) were analyzed. Most patients were treated by specialists (83.7%) and had moderate-to-severe asthma (91.0%). Overall, 7.6% of patients were prescribed ≥ 3 SABA canisters (defined as over-prescription). In patients prescribed SABA in addition to maintenance therapy, 47.4% were over-prescribed SABA. Most patients (95.4%) were prescribed a fixed-dose combination of an inhaled corticosteroid and a long-acting β2-agonist as maintenance therapy. Although asthma was well-controlled/partly-controlled in 91.6% of patients, 29.6% experienced ≥ 1 severe asthma exacerbation.

CONCLUSION

SABA over-prescription was reported in nearly 50% of patients prescribed SABA in addition to maintenance therapy, underscoring the need to align clinical practices with the latest evidence-based recommendations and educate physicians and patients on appropriate SABA use.

Increasing the accuracy of the asthma diagnosis using an operational definition for asthma and a machine learning method

INTRODUCTION

Analysis of the National Health Insurance data has been actively carried out for the purpose of academic research and establishing scientific evidences for health care service policy in asthma. However, there has been a limitation for the accuracy of the data extracted through conventional operational definition. In this study, we verified the accuracy of conventional operational definition of asthma, by applying it to a real hospital setting. And by using a machine learning technique, we established an appropriate operational definition that predicts asthma more accurately.

METHODS

We extracted asthma patients using the conventional operational definition of asthma at Seoul St. Mary's hospital and St. Paul's hospital at the Catholic University of Korea between January 2017 and January 2018. Among these extracted patients of asthma, 10% of patients were randomly sampled. We verified the accuracy of the conventional operational definition for asthma by matching actual diagnosis through medical chart review. And then we operated machine learning approaches to predict asthma more accurately.

RESULTS

A total of 4,235 patients with asthma were identified using a conventional asthma definition during the study period. Of these, 353 patients were collected. The patients of asthma were 56% of study population, 44% of patients were not asthma. The use of machine learning techniques improved the overall accuracy. The XGBoost prediction model for asthma diagnosis showed an accuracy of 87.1%, an AUC of 93.0%, sensitivity of 82.5%, and specificity of 97.9%. Major explanatory variable were ICS/LABA,LAMA and LTRA for proper diagnosis of asthma.

CONCLUSIONS

The conventional operational definition of asthma has limitation to extract true asthma patients in real world. Therefore, it is necessary to establish an accurate standardized operational definition of asthma. In this study, machine learning approach could be a good option for building a relevant operational definition in research using claims data.

Epidemiology of patients with asthma in Korea: Analysis of the NHISS database 2006-2015

Background

There has been a concerning increase in the prevalence and socioeconomic burden of asthma in Korea. Korea's National Health Insurance System (NHIS) covers insurance payment and claims management for all Koreans. Using National Health Insurance Sharing Service (NHISS) claims data. This study aimed to investigate patterns of healthcare utilization and direct cost in patients with asthma over a 10-year period.

Methods

In this retrospective population-based study, we examined NHISS claims records between July 2005 and June 2016 and investigated healthcare utilization among patients with asthma based on age group and severity of disease (non-severe asthma [NSA] and severe asthma [SA]).

Results

From 2006 to 2015, the total number of patients with asthma in Korea steadily increased from 743 968 to 2 286 309, with a corresponding increase in prevalence from 1.62% to 4.74%. The proportion of patients with SA decreased from 3.16% in 2006 to 1.56% in 2015; the proportion was consistently higher in men than in women. In addition, patients with SA had a higher cost per outpatient visit than patients with NSA, and the number of outpatient visits per year increased. The inhaled corticosteroid (ICS) prescription rate among patients with asthma decreased from 22.9% in 2006 to 15.7% in 2015. Furthermore, for a period of 10 years, more than 40% of patients with SA have been prescribed short-acting β-2 agonists (SABAs).

Conclusions

Although patients with SA comprised a small proportion of patients with asthma, they incurred greater medical costs per person. The pharmaceutical prescription pattern indicated a lack of ICS-based prescriptions and frequent SABA prescriptions.

Associations Between Asthma Diagnosis/Asthma Exacerbation and Previous Proton-Pump Inhibitor use: A Nested Case-Control Study Using a National Health Screening Cohort

Background: Proton-pump inhibitors (PPIs) block acid secretion from gastric parietal cells; however, recent studies have reported that PPIs have antioxidant and anti-inflammatory properties in various cells. Newer PPIs are stronger inhibitors of acid secretion; however, the anti-inflammatory effects of these drugs have not been assessed. We evaluated anti-inflammatory effect of PPIs on the development of asthma/asthma exacerbation (AE) in a national health screening cohort.

Methods: This case-control study comprised 64,809 participants with asthma who were 1:1 matched with controls from the Korean National Health Insurance Service-Health Screening Cohort. Conditional logistic regression analysis was used to evaluate the effect of previous PPI use on an asthma diagnosis in all participants. Unconditional logistic regression was used to assess the effect of PPI use on AE in participants with asthma. These relationships were estimated in a subgroup analysis according to PPI generation.

Results: Overall, PPI use increased the risk of asthma diagnosis [adjusted odds ratio (aOR) = 1.29, 95% confidence interval (CI) = 1.23–1.35, p < 0.001]. Use of the first-generation PPIs was associated with asthma (aOR = 1.34, 95% CI = 1.18–1.52, p < 0.001), while use of second-generation PPIs was not (aOR = 0.97, 95% CI = 0.82–1.15, p = 0.748). In contrast, overall PPI use decreased the risk of AE in participants with asthma (aOR = 0.79, 95% CI = 0.75–0.84, p < 0.001), although this effect was observed only for second-generation PPIs (aOR = 0.76, 95% CI = 0.65–0.89, p = 0.001).

Conclusion: PPI use increased the risk for subsequent asthma diagnosis. However, this effect was confined to first-generation PPIs. Second-generation PPIs decreased the risk of AE.

The association between chronic rhinosinusitis and proton pump inhibitor use: a nested case-control study using a health screening cohort

This study aimed to evaluate the relationship between chronic rhinosinusitis (CRS) and proton pump inhibitor (PPI) use in a Korean population. The Korea National Health Insurance Service-National Sample Cohort was assessed from 2002 to 2013. Patients with CRS (n = 7194) and control participants (n = 28,776) were matched by random order at a 1:4 ratio for age, sex, income group, region of residence, and index date. We analyzed PPI use by patients with and without CRS. ICD-10 codes defined CRS, and claim codes defined previous PPI use. Conditional logistic regression analyzed the crude and adjusted odds ratios (ORs) with 95% confidence intervals (CI). Subgroup analyses were performed according to age and sex. There was a difference in PPI prescription history and prescription duration between the CRS and control groups. The rate of CRS was higher in current (33.8% [263/778]) and past (26.3% [713/2708]) PPI users than PPI non-users (19.1% [6218/32,484], P < 0.001). The adjusted OR (aOR) of CRS with/without nasal polyps was 1.71 (95% CI 1.46–2.02, P < 0.001) and 1.28 (95% CI 1.16–1.41, P < 0.001) in current and past PPI users, respectively. Irrespective of PPI prescription days, PPI use was associated with higher CRS occurrence (aOR 1.46; 95% CI 1.26–1.69, P < 0.001) in the 30–89-day PPI user group. The subgroup analyses results were consistent. The ORs of CRS were higher in PPI users than in the controls, and consistently so in all age and sex groups.

Association between asthma or chronic obstructive pulmonary disease and chronic otitis media

We hypothesized that asthma/chronic obstructive pulmonary disease (COPD) might increase the risk of chronic otitis media (COM), as asthma or COPD affects other diseases. The aim of this research was to investigate whether the incidence of COM is affected by a diagnosis of asthma or COPD in patients compared to matched controls from the national health screening cohort. A COM group (n = 11,587) and a control group that was 1:4 matched for age, sex, income, and residence area (n = 46,348) were selected. The control group included participants who never received treatment for COM from Korean National Health Insurance Service-Health Screening Cohort from 2002 to 2015. The crude and adjusted odds ratios (ORs) of previous asthma/COPD before the index date for COM were analyzed using conditional logistic regression. The analyses were stratified by age, sex, income, and region of residence. The period prevalence of asthma (17.5% vs. 14.3%, p < 0.001) and COPD (6.6% vs. 5.0%, p < 0.001) were significantly higher in the COM group than in the control group. In addition, the odds of asthma and COPD were significantly higher in the COM group than in the control group. Both asthma (adjusted OR 1.23, 95% confidence interval [CI] 1.16-1.31, p < 0.001) and COPD (adjusted OR 1.23, 95% CI 1.13-1.35, p < 0.001) increased the ORs for COM. This positive association between asthma/COPD and COM indicates that asthma/COPD might increase the incidence of COM.

Real-world Treatment Patterns, Outcomes, and Healthcare Resource Utilization in Newly Treated Korean Patients With Asthma: A Retrospective Cohort Study

Purpose

Although asthma treatment guidelines recommend regular inhaled medication, real-world treatment patterns and outcomes in South Korea have not been examined. We examined real-world treatment patterns and outcomes among patients treated for asthma in South Korea.

Methods

This retrospective cohort study utilized data from the South Korean National Health Insurance database (2013–2016). Newly treated patients with asthma aged ≥18 years without history of chronic obstructive pulmonary disease were included. Initial and maintenance medication prescriptions were examined. Treatment discontinuation and switch were described. Asthma exacerbation rates, poor asthma control, and healthcare resource utilization (HRU) were compared between maintenance treatment groups (inhaled versus oral) using adjusted incidence rate ratios (aIRR) and hazard ratios (aHR).

Results

Overall, 1,054,707 patients initiated any asthma medication; 37,868 patients initiated inhaled (n = 9,983, 26.4%) or oral (n = 27,885, 73.6%) maintenance medication. More patients initiating inhaled versus oral asthma medication discontinued treatment within 12 months (94.4% vs. 86.3%; P < 0.0001). Patients treated with inhaled and oral medication switched treatment (2.5% and 2.3%; P = 0.4160, respectively). Patients initiating inhaled medication had significantly lower rates of asthma exacerbation (aIRR, 0.52; 95% CI, 0.39–0.69), lack of asthma control (aHR, 0.55; 95% CI, 0.48–0.62; P < 0.0001), all-cause and asthma-related HRU versus oral medication.

Conclusions

Despite current asthma guidelines, more patients in South Korea were prescribed oral than inhaled medications, resulting in suboptimal asthma management and increased HRU. This study highlights the need to reduce oral corticosteroid prescriptions for optimized treatment in asthma management.

Association of sudden sensorineural hearing loss with asthma: a longitudinal follow-up study using a national sample cohort

OBJECTIVE

To investigate the risk of sudden sensorineural hearing loss (SSNHL) in asthma patients.

DESIGN

A longitudinal follow-up study using a retrospective cohort SETTING: The 2002-2013 Korean National Health Insurance Service-Health Screening Cohort PARTICIPANTS AND INTERVENTIONS: The ≥40 years old Korean population were enrolled. The asthma patients were 1:1 matched with the control group for age, sex, income and region of residence.

MAIN OUTCOME MEASURE

The occurrence of SSNHL was followed in both asthma and control groups. The stratified Cox proportional hazard model was used. Age, sex, income and region of residence were stratified, and Charlson Comorbidity Index scores, obesity, smoking, alcohol consumption and atopic dermatitis histories were adjusted. Subgroup analysis was performed according to age, sex, obesity, smoking and alcohol consumption.

RESULTS

The results showed that 1.0% (877/90 564) of the asthma group and 0.8% (706/90,564) of the control group exhibited SSNHL (p<0.001). The asthma group demonstrated a higher HR for SSNHL than the control group (adjusted HR 1.23, 95% CI 1.11 to 1.36, p<0.001). According to age and sex, the female subgroup showed elevated HRs for SSNHL in asthma patients. Both the non-smoker and current smoker groups demonstrated higher HRs for SSNHL in asthma patients than in controls. According to alcohol consumption or obesity, the <1 time a week alcohol consumption group and normal weight and severe obesity groups showed higher HRs for SSNHL in asthma patients than in the controls.

CONCLUSIONS

Adult asthma patients had a higher risk of SSNHL than the control participants matched for demographic and socioeconomic factors.

Prescription Patterns of Oral Corticosteroids for Asthma Treatment and Related Asthma Phenotypes in University Hospitals in Korea

Purpose

Oral corticosteroids (OCSs) are frequently prescribed for asthma management despite their adverse effects. An understanding of the pattern of OCS treatment is required to optimize asthma treatment and reduce OCS usage. This study evaluated the prescription patterns of OCSs in patients with asthma.

Methods

This is a retrospective multicenter observational study. We enrolled adult (≥18 years) patients with asthma who had been followed up by asthma specialists in 13 university hospitals for ≥3 years. Lung function tests, the number of asthma exacerbations, and prescription data, including the days of supply and OCS dosage, were collected. The clinical characteristics of OCS-dependent and exacerbation-prone asthmatic patients were evaluated.

Results

Of the 2,386 enrolled patients with asthma, 27.7% (n = 660) were OCS users (the median daily dose of OCS was 20 mg/day prednisolone equivalent to a median of 14 days/year). OCS users were more likely to be female, to be treated at higher asthma treatment steps, and to show poorer lung function and more frequent exacerbations in the previous year than non-OCS users. A total of 88.0% of OCS users were treated with OCS burst with a mean dose of 21.6 ± 10.2 mg per day prednisolone equivalent to 7.8 ± 3.2 days per event and 2.4 times per year. There were 2.1% (51/2,386) of patients with OCS-dependent asthma and 9.5% (227/2,386) with exacerbation-prone asthma. These asthma phenotypes were consistent over the 3 consecutive years in 47.1% of OCS-dependent asthmatic patients and 34.4% of exacerbation-prone asthmatic patients when assessed annually over the 3-year study period.

Conclusions

We used real-world data from university hospitals in Korea to describe the OCS prescription patterns and relievers in asthma. Novel strategies are required to reduce the burden of OCS use in patients with asthma.

Association Between Asthma and Meniere's Disease: A Nested Case-Control Study

OBJECTIVES/HYPOTHESIS

This study aimed to investigate the association between Meniere's disease and prior history of asthma.

STUDY DESIGN

A nested case-control study.

METHODS

Among the patients aged ≥40 years from the Korean National Health Insurance Service-Health Screening Cohort 2002-2015, 7,734 diagnosed with Meniere's disease between 2004 and 2015 were enrolled in this study. From the 505,834 participants without a prior history of Meniere's disease, 30,936 control participants were selected based on age, sex, income, and region of residence. The presence of a prior history of asthma before the diagnosis of Meniere's disease was compared between the Meniere's disease group and control group using conditional logistic regression with odds ratios (ORs) and 95% confidence intervals (95% CIs).

RESULTS

Prior history of asthma was associated with 1.30 (1.21-1.39) times higher odds of Meniere's disease (E-value = 1.92 [1.71]). Both allergic asthma and nonallergic asthma patients demonstrated higher odds of Meniere's disease than the control group (adjusted OR = 1.21 [1.08-1.36] and E-value = 1.72 [1.37] for allergic asthma; adjusted OR = 1.26 [1.17-1.36] and E-value = 1.83 [1.60] for nonallergic asthma).

CONCLUSIONS

This study is the first to demonstrate a positive relationship between Meniere's disease and prior asthma history in adults. The association between prior asthma history and Meniere's disease was noted in both allergic and nonallergic asthma cases. The potential development of Meniere's disease should be considered when managing the asthma patients with dizziness or vertigo.

LEVEL OF EVIDENCE

3 Laryngoscope, 2021.

The Impact of Air Pollutants and Meteorological Factors on Chronic Obstructive Pulmonary Disease Exacerbations: A Nationwide Study

RATIONALE Chronic obstructive lung disease (COPD) is a chronic progressive disease. Although smoking is the most important risk factor, 30% of COPD patients are never smokers, and environmental agents are also influential. The effects of air pollutants and meteorological factors on COPD exacerbations have not been studied extensively. OBJECTIVE We aimed to investigate the air pollutants and meteorological factors that impact the incidence of COPD exacerbations. METHODS We obtained clinical data of COPD exacerbation cases from The National Health Insurance Service (NHIS) and merged it with 24-hour average values of air pollutants and meteorological factors from national databases. Patients who reside in eight metropolitan cities, where observatory stations are densely located, were selected for analysis. RESULTS In 1,404,505 COPD patients between 2013 and 2018, 15,282 COPD exacerbations leading to hospitalization or emergency room visits were identified. Among the various air pollutants and meteorological factors, particulate matter (PM)2.5, PM10, NO2, SO2, CO, O3, average temperature and diurnal temperature range (DTR) were associated with COPD exacerbations. GAM model analysis with cubic splines showed an inverted U-shaped relationship with PM2.5, PM10, CO, NO2, SO2, O3, DTR and humidity, while it displayed a U-shaped pattern with the average temperature. Distinct patterns were found from 2015-2016 to 2017-2018. CONCLUSIONS PM2.5, PM10, CO, NO2, O3, SO2, average temperature, humidity, and DTR affected the incidence of COPD exacerbations in various patterns, up to 10 lag days.

Inhaled Corticosteroid-Containing Regimens Reduce Hospitalizations and Healthcare Costs among Elderly Asthmatics: Real-World Validation Using the National Health Insurance Claims Database

The high rates of mortality and hospitalization among elderly asthmatics, as well as their increasing healthcare costs have become an important public health issue. It would be worthwhile to assess whether inhaled corticosteroid (ICS) can resolve these problems. To explore ICS prescription rates for elderly asthmatics and the factors influencing them and to investigate their association with hospitalization and healthcare costs, we analyzed data from the National Health Insurance Claims Database for the same time frame (December 1 to February 28) across three different periods (2011-2012; 2014-2015; and 2017-2018), from which we identified 6,619, 5,619, and 6,880 elderly individuals, respectively. The prescription rates of ICS increased (52.8%, 65.5% and 68.8%, in the first, second and third survey period, respectively) and inversely the hospital admission rates declined (3.7%, 3.2% and 2.5%, in the first, second and third survey period, respectively). The total healthcare costs per month were significantly lower for patients who received ICS-containing regimens than for those who did not. A multivariate analysis revealed that increasing age, rural residence, receiving a prescription from a clinic, hospital admission, and prescription of asthma medications other than ICS were associated with non-prescription of ICS, whereas cross-boundary treatment increased the ICS-prescription rate. Our study suggests that increases in the prescription rate of ICS are associated with reduced hospital admission rates and lower medical costs in the real-world. ICS prescription rates in rural areas and at clinics, which remain low, need to be increased.

Association between Chronic Obstructive Pulmonary Disease and Ménière's Disease: A Nested Case-Control Study Using a National Health Screening Cohort

This study explored the relation between Ménière's disease and chronic obstructive pulmonary disease (COPD). The ≥40-year-old population of the Korean National Health Insurance Service-Health Screening Cohort was included. In total, 7734 Ménière's disease patients and 30,936 control participants were enrolled. Control participants were matched for age, sex, income, and region of residence with Ménière's disease participants. The odds of having Ménière's disease given a history of COPD were analyzed using conditional logistic regression. Subgroup analyses were conducted according to age, sex, income, and region of residence. The odds of having Ménière's disease were found to be 1.18-fold higher with a history of COPD than with no history of COPD (95% confidence intervals (CI) = 1.06-1.32, E-value (CI) = 1.64 (1.31)). The ≥60 years old, male, low-income, and rural subgroups showed increased odds of developing Ménière's disease when a history of COPD was reported. A history of COPD was associated with an increased risk of Ménière's disease in the adult population.

Asthma in Adult Patients with COVID-19. Prevalence and Risk of Severe Disease

Rationale: Health outcomes of people with coronavirus disease (COVID-19) range from no symptoms to severe illness and death. Asthma, a common chronic lung disease, has been considered likely to increase the severity of COVID-19, although data addressing this hypothesis have been scarce until very recently.Objectives: To review the epidemiologic literature related to asthma's potential role in COVID-19 severity.Methods: Studies were identified through the PubMed (MEDLINE) and medRxiv (preprint) databases using the search terms "asthma," "SARS-CoV-2" (severe acute respiratory syndrome coronavirus 2), and "COVID-19," and by cross-referencing citations in identified studies that were available in print or online before December 22, 2020.Measurements and Main Results: Asthma prevalence data were obtained from studies of people with COVID-19 and regional health statistics. We identified 150 studies worldwide that allowed us to compare the prevalence of asthma in patients with COVID-19 by region, disease severity, and mortality. The results of our analyses do not provide clear evidence of increased risk of COVID-19 diagnosis, hospitalization, severity, or mortality due to asthma.Conclusions: These findings could provide some reassurance to people with asthma regarding its potential to increase their risk of severe morbidity from COVID-19.

Hypertension and diabetes mellitus as risk factors for asthma in Korean adults: the Sixth Korea National Health and Nutrition Examination Survey

Background

Asthma is a chronic inflammatory disease that may associate with other chronic diseases such as hypertension and diabetes. We observed the effects of blood pressure (BP), fasting blood glucose (FBG), haemoglobin A1c (HbA1c) and insulin on asthma in Korean adults.

Methods

Data from 5045 adults were taken from the 2015 Sixth Korea National Health and Nutrition Examination Survey and analysed using a multiple logistic regression model.

Results

By age, the probability of asthma occurrence was 1.02 times higher (adjusted odds ratio [aOR] 1.02 [95% CI 1.01 to 1.03]). Specifically, asthma occurrence was increased in individuals >66 years of age (aOR 2.40 [95% CI 1.22 to 4.72]). The probability of asthma occurrence in females was higher than in males (aOR 1.73 [95% CI 1.02 to 2.84]). Hypertension and systolic blood pressure (SBP) were found to increase the probability of asthma occurrence by 1.43- and 1.03-fold, respectively. Diabetes mellitus (DM) was another factor that increased with the occurrence of asthma (aOR 1.75 [95% CI 1.06 to 3.02]). The probability of asthma occurrence was not increased with the FBG level, whereas HbA1c (aOR 1.38 [95% CI 1.03 to 1.84]) and insulin levels (aOR 1.02 [95% CI 1.01 to 1.04]) were shown to increase the occurrence of asthma.

Conclusions

Age, sex, hypertension, SBP, DM, HbA1c and insulin levels are all factors that may influence the occurrence of asthma in Korean adults. In particular, hypertension and diabetes emerge from the present study as potential associated factors for the development of asthma.

Bidirectional association between asthma and otitis media in children

BACKGROUND

This study explored the reciprocal association between otitis media and asthma in children.

METHODS

The 2002-2013 Korean Health Insurance Review and Assessment Service-National Sample Cohort participants < 15 years old were used. In study I, 14,665 asthma patients from 2002 through 2005 were selected. The asthma patients were matched 1:1 with the control I group, and the occurrence of otitis media was followed until 2013. In study II, 27,043 otitis media patients from 2002 through 2005 were selected. The otitis media patients were matched 1:1 with the control II group, and the occurrence of asthma was followed until 2013. Stratified Cox proportional hazard models were used to analyze the hazard ratio (HRs) of asthma for otitis media (study I) and otitis media for asthma (study II).

RESULTS

The HR for otitis media was 1.46 in asthma patients (95% confidence interval [CI] = 1.40-1.52, P < 0.001). The HR for asthma was 1.43 in otitis media patients (95% confidence interval [CI] = 1.36-1.50, P < 0.001).

CONCLUSION

Asthma and otitis media have a bidirectional association in children.

Specialist Perception of Severe Asthma in Korea: A Questionnaire Survey

The Working Group on Severe Asthma of the Korean Academy of Allergy and Clinical Immunology recently published an expert opinion paper on the management of severe asthma in Korea. When developing a consensus, the working group encountered several diagnostic and treatment issues and decided to perform a questionnaire survey of Korean specialists with regard to severe asthma. An e-mail with a uniform resource locator link to the questionnaire was sent to 121 asthma specialists, of whom 44.6% responded. The most commonly accepted definitions of severe asthma were a history of fatal exacerbation or an asthma-triggered need for mechanical ventilation, 3-4 oral corticosteroid (OCS) bursts/year, and maintenance of OCS therapy for 3-6 months per year. Before diagnosing severe asthma, most physicians contemplate chest computed tomography, seek to control chronic rhinosinusitis, and consider poor inhaler compliance. For patients with uncontrolled severe asthma accompanied by type 2 (T2)-high inflammation, most biologics available in Korea were considered appropriate, but gaps were apparent in terms of T2-low asthma treatments. These findings about specialist perception of diagnosis and treatment of severe asthma will inform the use of emerging new drugs and facilitate personalized therapy.

The Clinical Course of Asthma After Withdrawal of Inhaled Corticosteroids

BACKGROUND

Maintenance of inhaled corticosteroids (ICSs) is recommended in adults with asthma. However, adherence rates in patients with mild asthma and side effects of long-term ICS use can lead to withdrawal.

OBJECTIVE

To analyze the real-world outcomes of ICS withdrawal by analyzing data from the Korean National Health Insurance database.

METHODS

Based on claims data from the National Health Insurance of Korea between 2011 and 2014, we identified patients diagnosed with asthma without chronic obstructive pulmonary disease or long-term systemic steroid use who had an ICS medication possession rate of more than 50% in a year. We compared patients who received ICS consistently (maintenance group) with patients who had no ICS prescription for more than 6 months (withdrawal group). We evaluated exacerbation leading to prescription of systemic steroid and emergency department visit or hospitalization.

RESULTS

Excluding patients with chronic obstructive pulmonary disease and long-term systemic steroid users, we identified 145,511 patients for the asthma cohort (mean age, 60.0 years; ever-smoker, 63.5%): 132,175 maintained ICS and 13,336 withdrew ICS for more than 6 months. Only 71 patients (0.5%) experienced exacerbation leading to an emergency department visit or hospitalization in the withdrawal group. ICS was restarted within 1 year for 33.6% of the withdrawal group, and 90% of these patients restarted ICS within 158 days.

CONCLUSIONS

This nationwide study of patients with asthma, characterized by a high proportion of elderly and smokers, showed that ICS withdrawal in about 10% of patients appeared to confer relatively minimal harm and exacerbation leading to hospitalization was not common. Further prospective studies are warranted to carefully explore the safety of ICS withdrawal in younger, nonsmoking, and well-controlled patients with asthma.

Impact of the Combinations of Allergic Diseases on Myocardial Infarction and Mortality

BACKGROUND

Allergic rhinitis (AR), atopic dermatitis (AD), and asthma, each by itself, are known to be associated with a higher risk of cardiovascular disease. Each of these diseases often coexists with one another, but the effect of combined allergic diseases on the long-term risk of myocardial infarction (MI) and mortality remains unknown.

OBJECTIVE

To evaluate the effects of various combinations of the allergic triad on the risk of MI and mortality.

METHODS

Adult allergic disease patients without prior MI were enrolled from the nationwide health check-up data provided by the Korean National Health Insurance Service in 2009. The primary and secondary end points were all-cause death and MI.

RESULTS

A total of 9,548,939 individuals older than 20 years were selected for analysis. The prevalence of allergic diseases was 13.9% for AR, 0.4% for AD, and 2.7% for asthma. During a median 8.2 years of follow-up, 105,659 MIs and 298,769 deaths occurred. All allergic diseases were associated with an increased risk of MI (AR, adjusted hazard ratio [HR_adjust], 1.11, 95% CI, 1.10-1.13; AD, HR_adjust, 1.14, 95% CI, 1.06-1.24; asthma, HR_adjust, 1.37, 95% CI, 1.33-1.40), whereas mortality risk was increased only for patients with AD (HR_adjust, 1.15; 95% CI, 1.10-1.20) or asthma (HR_adjust, 1.41; 95% CI, 1.39-1.43). Among the combinations of allergic diseases, patients with both AD and asthma had the highest risk of mortality (HR_adjust, 1.71; 95% CI, 1.46-2.00) and MI (HR_adjust, 1.57; 95% CI, 1.15-2.16). The results were significant after adjusting for demographic characteristics, comorbidities, socioeconomic status, and lifestyle factors.

CONCLUSIONS

Patients with both AD and asthma have the highest risk of MI and mortality among all allergic disease combinations. Physicians should evaluate combinations of allergic conditions in allergic disease patients and promptly assess and manage their future risk of MI and mortality.

Coexisting COPD Increases Mortality in Patients With Corticosteroid-Dependent Asthma: A Nationwide Population-Based Study

PURPOSE

Chronic corticosteroid (CS) use is a risk factor for long-term mortality in asthmatic patients, and the presence of coexisting chronic obstructive pulmonary disease (COPD) is associated with a severe presentation and poor prognosis. However, the impact of coexisting COPD on long-term mortality in patients with CS-dependent asthma has not been well elucidated. This study aimed to determine the impact of coexisting COPD on long-term mortality in patients with CS-dependent asthma.

METHODS

A retrospective cohort of patients with CS-dependent asthma aged 40 years or older was established using records from the Korean National Health Insurance Service database for 2005 to 2015. We classified the subjects into 2 groups according to the presence of COPD and evaluated the hazard ratio (HR) for all-cause mortality in patients with COPD relative to those without COPD.

RESULTS

Of 8,021 patients with CS-dependent asthma, 3,121 (38.9%) had COPD. All-cause mortality was significantly greater in patients with CS-dependent asthma and COPD than in those without COPD (9,955/100,000 person-years vs. 5,585/100,100 person-years, P < 0.001). The adjusted HRs were 1.29 (95% confidence interval [CI], 1.21-1.38), and the associations were especially significant for chronic lower respiratory diseases (subdistribution HR, 2.30; 95% CI, 2.06-2.57) and lung cancer (subdistribution HR, 1.34; 95% CI, 1.02-1.78).

CONCLUSIONS

In this population-based retrospective cohort study, the presence of physician-recognized COPD was associated with greater all-cause mortality and greater risk of mortality due to chronic lower respiratory diseases and lung cancer in patients with CS-dependent asthma. Early recognition and appropriate management of COPD can improve treatment outcomes in patients with CS-dependent asthma.

Bidirectional association between GERD and asthma in children: two longitudinal follow-up studies using a national sample cohort

BACKGROUND

The causal relationship between asthma and gastroesophageal reflux disease (GERD) is unknown in children.

METHODS

The Korean Health Insurance Review and Assessment Service-National Sample Cohort 2002-2013 was used. The population age <15 years was selected. In study I, 86,096 asthmatic children were 1:1 matched with 86,096 control I participants. In study II, 532 GERD children were 1:2 matched with 1064 control II participants. The stratified Cox proportional hazard ratios for GERD in patients with asthma (study I) and asthma in patients with GERD (study II) were analyzed.

RESULTS

In total, 0.7% (583/86,096) of the asthma group and 0.5% (430/86,096) of the control I group had GERD (P < 0.001). The asthma group demonstrated a 1.36 times higher HR for GERD than the control I group (95% CI = 1.20-1.54, P < 0.001). Subgroup analyses according to age and sex showed consistent results. In total, 15.0% (80/532) of the GERD group and 10.0% (106/1,064) of the control II group had asthma (P < 0.001). The GERD group showed a 1.62-fold higher HR for asthma than the control II group (95% CI = 1.21-2.18, P < 0.001).

CONCLUSION

GERD and asthma demonstrated a bidirectional relationship in children.

Asthma increases the risk of herpes zoster: a nested case-control study using a national sample cohort

Background

This study aimed to complement previous studies on the risk of herpes zoster in the asthmatic adult population.

Methods

The Korean Health Insurance Review and Assessment Service—National Sample Cohort (HIRA-NSC) from 2002 through 2013 was used. A total of 64,152 participants with herpes zoster were matched for age, sex, income, region of residence, hypertension, diabetes, and dyslipidemia with 239,780 participants who were included as a control group. In both the herpes zoster and control groups, previous history of asthma were investigated. The crude and adjusted odds ratios (ORs) and 95% confidence intervals (CI) of asthma for herpes zoster were analyzed using unconditional logistic regression analysis. Subgroup analyses were conducted according to age and sex.

Results

Approximately 16.2% (9728/59,945) and 12.8% (30,752/239,780) of participants in the herpes zoster and control groups, respectively, had a previous history of asthma (P < 0.001). The herpes zoster group demonstrated a 1.32-times higher odds of asthma than the control group (95% CI 1.28–1.35, P < 0.001). The increased odds of asthma in the herpes zoster group persisted in all the age and sex subgroups.

Conclusions

The odds for asthma were higher in the herpes zoster group.

Bidirectional association between asthma and chronic rhinosinusitis: Two longitudinal follow-up studies using a national sample cohort

The aim of this study was to evaluate an epidemiologic association of asthma and chronic rhinosinusitis (CRS) using a national sample cohort of the Korean population. We collected data from the Korean Health Insurance Review and Assessment Service-National Sample Cohort between 2002 and 2013, and two different case-control cohorts were designed (1st: asthmatic patients matched in a 1:1 ratio with 204,119 non-asthmatics as control I, 2nd: CRS patients matched in a 1:4 ratio with 124,020 non-CRS patients as control II). Bidirectional association was examined using Cox proportional hazard models stratified by age, sex, income, and region of residence. Patients with asthma had an increased risk of developing CRS [adjusted hazard ratio (95% confidence interval) = 1.74 (1.67–1.80)], both with nasal polyps [1.55 (1.36–1.78)], without nasal polyps [1.74 (1.67–1.81)]. In the second cohort, patients with CRS had increased risk of developing asthma [1.85 (1.80–1.91)] with similar results for those with and without nasal polyps. The strongest association for risk of CRS was in 20–39 years old men with asthma [2.41 (1.97–2.96)], while the strongest association for increased risk of asthma in those with CRS group was also seen in this same subgroup [2.40 (2.18–2.63)]. CRS and asthma had a bidirectional influence on each other. CRS increased the risk of asthma, and asthma increased the risk of CRS, especially in young men.

Bronchiectasis and increased mortality in patients with corticosteroid-dependent severe asthma: a nationwide population study

BACKGROUND

Long-term corticosteroid (CS) use is associated with increased mortality in patients with asthma, and comorbid bronchiectasis is also associated with frequent asthma exacerbation and increased healthcare use. However, there is limited information on whether bronchiectasis further increases mortality in patients with CS-dependent asthma. This study examined the impact of bronchiectasis on mortality in patients with CS-dependent asthma.

METHODS

A retrospective cohort of patients with CS-dependent asthma ⩾18 years old was established using records from the Korean National Health Insurance Service database from 2005 to 2015. Patients with CS-dependent asthma with and without bronchiectasis were matched by age, sex, type of insurance, and Charlson comorbidity index. We evaluated the hazard ratio (HR) for all-cause mortality in patients with bronchiectasis compared with those without bronchiectasis.

RESULTS

The study cohort included 754 patients with CS-dependent asthma with bronchiectasis and 3016 patients with CS-dependent asthma without bronchiectasis. Patients with CS-dependent asthma with bronchiectasis had a higher all-cause mortality than those without bronchiectasis (8429/100,000 versus 6962/100,000 person-years, p < 0.001). The adjusted HR for mortality in patients with CS-dependent asthma with bronchiectasis relative to those without bronchiectasis was 1.33 (95% confidence interval, 1.18-1.50), and the association was primarily significant for respiratory diseases (subdistribution HR = 1.65, 95% confidence interval, 1.42-1.92).

CONCLUSIONS

Bronchiectasis further increases all-cause mortality in patients with CS-dependent asthma, a trend that was especially associated with respiratory diseases including chronic obstructive pulmonary disease. Strategies to improve treatment outcomes in patients with CS-dependent asthma with bronchiectasis are urgently needed to improve long-term survival.The reviews of this paper are available via the supplemental material section.

Increasing Prevalence and Mortality of Asthma With Age in Korea, 2002-2015: A Nationwide, Population-Based Study

Purpose

The prevalence of asthma is increasing globally as the world population increases; however, and the prevalence and mortality of asthma have not been extensively investigated. Also, the effects of severity and aging on asthma prevalence and mortality are unknown. We aimed to investigate trends of the prevalence and mortality of asthma as well as health care uses and costs over 14 years according to disease severity by using real-world data in Korea.

Methods

Using the National Health Insurance Sharing Service database, we extracted asthmatic patients having diagnosis codes of asthma and prescription records of antiasthmatic medications from 2002 to 2015 and categorized them according to asthma exacerbation and regular treatment. We defined asthma-associated death in terms of patients' prescription records within 3 months before all-cause death, then linked with the Cause of Death Statistics. The annual asthma-related health care uses and costs were analyzed.

Results

The prevalence rates of asthma (1.6% to 2.2%) and severe asthma (SA; 3.5% to 6.1% among total asthmatics) have increased steadily over the decade in Korea, where the proportion of elderly asthmatics having increased. The asthma-related health care uses and costs had increased during the study period with the highest uses/costs in SA. The asthma mortality had a steady rising trend from 16.2 to 28.0 deaths per 100,000 with the highest mortality in SA.

Conclusions

The prevalence and mortality of asthma as well as SA increases along with the burden of health care uses/costs. More active interventions, including changes in health care policies, are needed to reduce the prevalence and mortality of asthma, especially SA.

Bidirectional association between asthma and migraines in adults: Two longitudinal follow-up studies

The objective of this study was to evaluate the bidirectional association between asthma and migraines using control subjects matched by demographic factors. The Korean Health Insurance Review and Assessment Service - National Sample Cohort from 2002 to 2013 was used. In study I, 113,059 asthma participants were matched with 113,059 control I participants. In study II, 36,044 migraine participants were matched with 114,176 control II participants. The hazard ratios (HRs) of migraines in the asthma patients (study I) and asthma in the migraine patients (study II) were analyzed using stratified Cox proportional hazard models after adjusting for depression and the Charlson comorbidity index. In study I, 5.3% (6,017/ 113,059) of the asthma group and 3.4% (3,806/ 113,059) of the control I group had migraines (P < 0.001). The asthma group demonstrated an adjusted HR of 1.47 for migraine (95% confidence interval (CI) = 1.41–1.53, P < 0.001). In study II, 15.4% (5,548/36,044) of the migraine group and 10.6% (15,271/144,176) of the control group had asthma (P < 0.001). The migraine group showed an adjusted HR of 1.37 for asthma (95% CI = 1.33–1.41, P value < 0.001). Asthma and migraines are reciprocally associated.

Increased mortality in patients with corticosteroid-dependent asthma: a nationwide population-based study

INTRODUCTION

Chronic systemic corticosteroid (CS) therapy is associated with an increased risk of mortality in patients with many chronic diseases. However, it has not been elucidated whether chronic systemic CS therapy is associated with increased mortality in patients with asthma. The aim of this study was to determine the effects of chronic systemic CS therapy on long-term mortality in adult patients with asthma.

METHODS

A population-based matched cohort study of males and females aged ≥18 years with asthma was performed using the Korean National Health Insurance Service database from 2005 to 2015. Hazard ratio (HR) with 95% confidence interval for all-cause mortality among patients in the CS-dependent cohort (CS use ≥6 months during baseline period) relative to those in the CS-independent cohort (CS use <6 months during baseline period) was evaluated.

RESULTS

The baseline cohort included 466 941 patients with asthma, of whom 8334 were CS-dependent and 458 607 were CS-independent. After 1:1 matching, 8334 subjects with CS-independent asthma were identified. The HR of mortality associated with CS-dependent asthma relative to CS-independent asthma was 2.17 (95% CI 2.04-2.31). In patients receiving low-dose CS, the HR was 1.84 (95% CI 1.69-2.00); in patients receiving high-dose CS, the HR was 2.56 (95% CI 2.35-2.80).

CONCLUSIONS

In this real-world, clinical practice, observational study, chronic use of systemic CS was associated with increased risk of mortality in patients with asthma, with a significant dose-response relationship between systemic CS use and long-term mortality.

Bidirectional Association Between GERD and Asthma: Two Longitudinal Follow-Up Studies Using a National Sample Cohort

BACKGROUND

A relation between gastroesophageal reflux disease (GERD) and asthma has been suggested; however, causality has not been investigated.

OBJECTIVE

This study aimed to delineate the causal relation between GERD and asthma.

METHODS

Participants of the Korean National Health Insurance Service-National Sample Cohort 2002-2013 who were ≥20 years old were selected for this study. In study I, 116,502 patients with GERD were matched in a 1:2 ratio to 233,004 control I participants, and the hazard ratio (HR) of asthma in patients with GERD was analyzed. In study II, 104,146 patients with asthma were matched in a 1:1 ratio to 104,146 control II participants, and the HR for GERD in patients with asthma was analyzed. A stratified Cox-proportional hazards model was used. Subgroup analyses were performed according to age and sex.

RESULTS

In study I, 12.5% (14,595 of 116,502) of the GERD group and 7.8% (18,135 of 233,004) of the control I group presented asthma (P < .001). The GERD group demonstrated a 1.46-fold higher HR for asthma than the control I group (95% confidence interval [CI] = 1.42-1.49, P < .001). In study II, 16.9% (17,582 of 104,146) of the asthma group and 11.9% (12,393 of 104,146) of the control II group presented GERD (P < .001). The asthma group showed a 1.36-fold higher HR for GERD than the control II group (95% CI = 1.33-1.39, P < .001). All age and sex subgroups presented consistent results.

CONCLUSION

GERD and asthma had a bidirectional relation in the study population.

The effect of low body mass index on the development of chronic obstructive pulmonary disease and mortality

BACKGROUND

Sarcopenia may worsen disease progression and lead to poor outcomes in chronic obstructive pulmonary disease (COPD).

OBJECTIVES

We aimed to determine the effect of BMI on the development of COPD and mortality.

METHODS

We enrolled 437 584 participants registered in the physical health check-up cohort database of the Korean National Health Interview Survey from 2002 to 2003, and we defined COPD diagnosis based on the ICD-10 code and prescribed medication. BMI (kg m^-2 ) classified them to five groups (low BMI < 18.5, normal BMI 18.5-23, overweight 23-25, obesity 25-30, severe obesity ≥30) at baseline.

RESULTS

Participants in the low BMI group had a significantly higher rate of COPD development for 13 years (7.6%) than those in other groups (3.4-4.1%, P < 0.0001). Amongst never or light smokers, COPD development in the low BMI group (5.6-6.7%) was significantly higher than that in other groups (2.8-4.7%). Similarly, amongst participants with a smoking history of ≥30 years, COPD development in the low BMI group (20.1%) was higher than those in other groups (8.4-12.4%). On multivariable analysis, normal or higher than normal body weight was significantly protective against the development of COPD (hazard ratio [HR], 0.609-0.739,) compared to low BMI. COPD-free-survival (HR, 0.491-0.622) and overall survival (HR, 0.440-0.585) were also better in them compared to those with low BMI (all P < 0.0001).

CONCLUSIONS

Low BMI is an important risk factor for COPD development and mortality. Maintaining adequate body weight may reduce the risk for COPD development and mortality.

Increased risk of psoriasis in children and elderly patients with asthma: a longitudinal follow-up study using a national sample cohort

BACKGROUND

Several previous studies reported the elevated risk of asthma in children with psoriasis. This study aimed to extend previous research regarding the risk of psoriasis in children with asthma to an entire population subdivided by age.

METHODS

The 2002-2013 Korean Health Insurance Review and Assessment Service-National Sample Cohort (HIRA-NSC) was used. The 167,693 participants with asthma were matched with 167,693 control participants for age, sex, income, region of residence, hypertension history, diabetes history, and dyslipidemia history. In both the asthma and control groups, the occurrences of asthma were investigated. The crude and adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for psoriasis with respect to asthma status were determined using stratified Cox proportional hazards models. Subgroup analyses were conducted according to age and sex.

RESULTS

The prevalence of psoriasis was 0.5% (95% CI, 0.4% to 0.5%; n = 771/167,693) in the asthma group and 0.4% (95% CI, 0.3% to 0.4%; n = 589/167,693) in the control group (p < 0.001). The asthma group (adjusted HR = 1.19; 95% CI, 1.07 to 1.33; p = 0.002) demonstrated higher HRs for psoriasis than did the control group. This result was consistent in the <15 years old, ≥60 years old, and women subgroups.

CONCLUSION

Asthma was associated with the elevated risk of psoriasis. The possible risk of psoriasis needs to be considered when managing asthma patients. Future study is warranted for the risk of psoriasis according to the endotypes of asthma.

Risk of neurodegenerative dementia in asthma patients: a nested case-control study using a national sample cohort

OBJECTIVES

This study investigated the risk of neurodegenerative dementia following asthma.

DESIGN

A nested case-control study SETTING: The ≥60-year-old population was selected from the Korean Health Insurance Review and Assessment Service - National Sample Cohort from 2002 to 2013.

PARTICIPANTS AND INTERVENTIONS

The 11 442 dementia cases were matched with 45 768 control cases for age, sex, income, region of residence, hypertension, diabetes and dyslipidaemia. Asthma was classified using International Classification of Disease-10 (ICD-10) codes (J45 and J46) and medication history. Dementia was identified based on ICD-10 codes (G30 and F00).

PRIMARY AND SECONDARY OUTCOME MEASURES

The ORs of a previous history of asthma in patients with dementia were analysed using conditional logistic regression analysis stratified for age, sex, income, region of residence, hypertension, diabetes and dyslipidaemia. Subgroup analysis was performed according to age and sex.

RESULTS

Overall, 22.6% (2587/11 442) and 22.3% (10 229/45 768) of the cases in the dementia and control groups, respectively, had a previous history of asthma. The OR for asthma in the dementia group was not higher than that in the control group (adjusted OR=0.97, 95% CI 0.92 to 1.02, p=0.207). All age and sex subgroups demonstrated consistent results.

CONCLUSIONS

Asthma was not related to an increased risk of dementia.

Tonsillectomy does not reduce asthma in children: A longitudinal follow-up study using a national sample cohort

This study aimed to investigate the occurrence of tonsillectomy in asthmatic children using a control group with a comparable frequency of a preoperative history of asthma. Asthmatic children ≤15 years old were collected from the Korean Health Insurance Review and Assessment Service - National Sample Cohort (HIRA-NSC) from 2002 through 2013. In study I, asthmatic children who had undergone a tonsillectomy (n = 2,326) and control I participants (n = 9,304) were selected and matched 1:4 for age, sex, income, and region of residence but not a preoperative history of asthma. In study II, a preoperative history of asthma was additionally matched for between the tonsillectomy (n = 2,280) and the new control II participants (n = 9,120). The margin of equivalence of difference (control-tonsillectomy) for asthma was set at -0.05 to 0.05 per year. In addition, repeated measures ANOVA was performed for tonsillectomy according to yearly changes in asthma, status asthmaticus, and admission. In study I, the preoperative frequencies of asthma, status asthmaticus, and admission were higher in the tonsillectomy group than in the control group (P ≤ 0.001). The frequencies of postoperative asthma, status asthmaticus, and admission were lower in the tonsillectomy group than in the control I group for 3 years. In study II, the frequencies of postoperative 1-, 2-, and 3-year asthma and admission were not lower in the tonsillectomy group than in the control II group. Tonsillectomy did not further reduce the frequency of asthma in patients who underwent this procedure compared to the control group when a preoperative history of asthma history was equally matched between the two groups.

Increased risk of appendectomy in patients with asthma: A nested case-control study using a national sample cohort

The study aimed to expand previous data regarding an association between asthma and appendectomy in children compared with the population of all ages.The Korean Health Insurance Review and Assessment Service-National Sample Cohort from 2002 through 2013 was used. In all, 22,030 participants who underwent appendectomy were matched for age, sex, income, region of residence, hypertension, diabetes, and dyslipidemia with 88,120 participants who were included as a control group. In both the appendectomy and control groups, previous history of asthma was investigated. Appendectomy for appendicitis was identified based on a surgical code (International Classification of Disease-10 [ICD-10]: K35). Asthma was classified using an ICD-10 code (J45 and J46) and medication history. The crude and adjusted odds ratios (ORs) and 95% confidence intervals (CIs) of asthma for appendectomy were analyzed using conditional logistic regression analysis. Subgroup analyses were conducted according to age and sex.Approximately 15.2% (3358/22,030) of individuals in the appendectomy group and 13.3% (11,749/88,120) of those in the control group had asthma (P < .001). The appendectomy group demonstrated a higher adjusted odds of asthma than the control group (adjusted OR 1.18, 95% CI 1.13-1.23, P < .001). This result was consistent in the subgroups divided according to age and sex.The odds for asthma were higher in the appendectomy group than in the control group.

Analysis of the Relationship between Adult Asthma and Stroke: A Longitudinal Follow-Up Study Using the Korean National Sample Cohort

Several previous studies demonstrated the risk of stroke in asthma patients. The aim of this study was to evaluate the risk of hemorrhagic and ischemic stroke in asthma patients, independent of age, sex, income, region of residence, and past medical histories. The Korean Health Insurance Review and Assessment Service-National Sample Cohort from 2002 through 2013 was used. Overall, 111,364 asthma patients ≥ 20 years old were matched to 111,364 control participants for age, sex, income, region of residence, hypertension, diabetes, and dyslipidemia. Asthma was classified using ICD-10 codes (J45 and J46) and medication history. The admission histories were investigated for hemorrhagic stroke (I60-I62) and ischemic stroke (I63) using ICD-10 codes. The crude and adjusted (age, sex, income, region of residence, hypertension, diabetes, dyslipidemia, ischemic heart disease, and depression) hazard ratios (HRs) for hemorrhagic and ischemic stroke in asthma patients were analyzed using a Cox proportional hazards model. Subgroup analyses were conducted according to age and sex. Hemorrhagic and ischemic stroke were found in 0.7% (795/117,364) and 2.4% (922/117,364) of the asthma group and in 0.8% (922/117,364) and 2.6% (93,079/117,364) of the control group, respectively. The asthma group demonstrated adjusted HRs of 0.86 (95% confidence interval [CI] = 0.78-0.94, p = 0.002) for hemorrhagic stroke and 0.91 (95% CI = 0.86-0.95, p = 0.002) for ischemic stroke. None of the subgroups of asthma patients showed higher HRs for stroke. Asthma did not elevate the risk of either hemorrhagic or ischemic stroke.

Increased risk of asthma in patients with rheumatoid arthritis: A longitudinal follow-up study using a national sample cohort

The aim of this study was to evaluate the risk of asthma in rheumatoid arthritis patients using matched control group for socioeconomic factors and past medical history. Adults >20 years old were collected from the Korean Health Insurance Review and Assessment Service - National Sample Cohort (HIRA-NSC) from 2002 through 2013. A total of 6,695 individuals with rheumatoid arthritis were matched for age, sex, income, region of residence, hypertension, diabetes, and dyslipidemia with 26,780 individuals included in a control group. In both the rheumatoid arthritis and control groups, subjects' history of asthma was evaluated. Asthma (J45 and J46) and rheumatoid arthritis (M05 and M06) were included based on the International Classification of Disease-10 (ICD-10) codes and medication history. The crude and adjusted (depression and Charlson Comorbidity Index) hazard ratios (HRs) and 95% confidence intervals (CI) of asthma for rheumatoid arthritis patients were analyzed using a stratified Cox proportional hazard model. Subgroup analyses were conducted according to age and sex, number of treatment histories, and medication histories. Approximately 16.4% (1,095/6,695) of rheumatoid arthritis group and 13.0% (3,469/26,780) of the control group had asthma (P < 0.001). The rheumatoid arthritis group demonstrated a higher adjusted HR for asthma than the control group (adjusted HR = 1.23, 95% CI = 1.15-1.32, P < 0.001). This result was consistent in all subgroups. Rheumatoid arthritis was related to an increase risk of asthma.

Association Between Asthma and Depression: A National Cohort Study

BACKGROUND

Patients with asthma often suffer from depression and vice versa. However, the temporal relationship between the 2 diseases has remained elusive.

OBJECTIVE

The aim of this study was to determine the bidirectional relationship between asthma and depression in adults, using national cohort samples in Korea.

METHODS

Using the national cohort from the study by the Korean Health Insurance Review and Assessment Service, patients with asthma and control participants were selected and matched by age group, sex, income group, region of residence, and medical histories. A stratified Cox proportional hazards model was used to analyze the hazard ratio (HR) of asthma with depression (study 1) and depression with asthma (study 2).

RESULTS

In study 1, the HR of depressive disorders was significantly higher in patients with asthma than in patients without asthma (HR, 1.35; 95% CI, 1.31-1.40). In study 2, the HR of asthma in patients with depression was significantly higher than that in patients without depression (HR, 1.25; 95% CI, 1.21-1.29).

CONCLUSION

A bidirectional association between asthma and depression was observed in this study.

Changing Disease Trends in the Northern Gyeonggi-do Province of South Korea from 2002 to 2013: A Big Data Study Using National Health Information Database Cohort

Objectives

To investigate the chronological patterns of diseases in Northern Gyeonggi-do province, South Korea, and compare these with national data.

Methods

A National Health Insurance cohort based on the National Health Information Database (NHID Cohort 2002–2013) was used to perform a retrospective, population-based study (46,605,433 of the target population, of which 1,025,340 were randomly sampled) to identify disease patterns from 2002 to 2013. Common diseases including malaria, cancer (uterine cervix, urinary bladder, colon), diabetes mellitus, psychiatric disorders, hypertension, intracranial hemorrhage, bronchitis/bronchiolitis, peptic ulcer, and end stage renal disease were evaluated.

Results

Uterine cervix cancer, urinary bladder cancer and colon cancer had the greatest rate of increase in Northern Gyeonggi-do province compared with the rest of the country, but by 2013 the incidence of these cancers had dropped dramatically. Acute myocardial infarction and end stage renal disease also increased over the study period. Psychiatric disorders, diabetes mellitus, hypertension and peptic ulcers showed a gradual increase over time. No obvious differences were found for intracranial hemorrhage or bronchitis/bronchiolitis between the Northern Gyeonggi-do province and the remaining South Korean provinces. Malaria showed a unique time trend, only observed in the Northern Gyeonggi province, peaking in 2004, 2007 and 2009 to 2010.

Conclusion

This study showed that the Northern Gyeonggi-do province population had a different disease profile over time, compared with collated data for the remaining provinces in South Korea. “Big data” studies using the National Health Insurance cohort database can provide insight into the healthcare environment for healthcare providers, stakeholders and policymakers.

Changing patterns of adult asthma incidence: results from the National Health Insurance Service-National Sample Cohort (NHIS-NSC) database in Korea

This study was conducted to assess the changes in the annual incidence of adult asthma in Korea where the prevalence of asthma had increased steadily in recent decades. A population-based cohort study was conducted using the National Health Insurance Service–National Sample Cohort (NHIS-NSC), which consisted of 746,816 adults aged >20 years between 2004 and 2012. Asthma was defined by two or more physician claims on the basis of a primary diagnostic code for asthma and administration of asthma medications within 1 year. The incidence rates and annual percent change were calculated, and the influence of age and sex on the incidence rates was studied. The annual asthma incidence increased from 3.63 in 2004 to 6.07 per 1,000 person-years in 2008. Since 2008, the asthma incidence did not change significantly. The asthma incidence was higher in women than in men throughout the study periods (p < 0.001) and higher in older than younger age groups (p < 0.001). The asthma incidence did not change in all ages since 2008, except for the 20 s who showed a steady increase. The incidence of asthma in adults reached plateau in Korea, which is consistent with the results from studies in other countries.

Significant predictors of medically diagnosed chronic obstructive pulmonary disease in patients with preserved ratio impaired spirometry: a 3-year cohort study

Background

Preserved ratio impaired spirometry (PRISm) is an incompletely understood respiratory condition. We investigated the incidence and significant predictive factors of chronic obstructive pulmonary disease (COPD) in PRISm patients.

Methods

From 11,922 subjects registered in the Korea National Health and Nutrition Examination Survey, never or light smokers, young subjects, and those already medically diagnosed with COPD (defined by ICD-10 code and prescribed medication) were excluded. The 2666 remaining subjects were categorized into PRISm (normal forced expiratory volume in the first second [FEV₁]/force vital capacity [FVC] [≥ 0.7] and low FEV₁ (< 80%); n = 313); normal (n = 1666); and unrevealed COPD groups (FEV₁/FVC ratio <  0.7; n = 687). These groups were compared using matched Health Insurance Review and Assessment Service data over a 3-year follow-up.

Results

COPD incidence in PRISm patients (17/1000 person-year [PY]) was higher than that in normal subjects (4.3/1000 PY; P <  0.001), but lower than that in unrevealed COPD patients (45/1000 PY; P < 0.001). PRISm patients visited hospitals, took COPD medication, and incurred hospitalization costs more frequently than normal subjects, but less frequently than unrevealed COPD patients. In the overall sample, age, FVC, FEV₁, dyspnea, and wheezing were significant predictors of COPD, but in PRISm patients, only age (OR, 1.14; P = 0.002) and wheezing (OR, 4.56; P = 0.04) were significant predictors.

Conclusion

PRISm patients are likely to develop COPD, and should be monitored carefully, especially older patients and those with wheezing, regardless of lung function.

Association between diabetes and asthma: Evidence from a nationwide Korean study

BACKGROUND

Type 2 diabetes and asthma share a common pathophysiology: "chronic inflammation." However, it is unclear whether patients with type 2 diabetes are at increased risk of asthma.

OBJECTIVE

To investigate the effect of type 2 diabetes on asthma using data from a large population-based study in Korea.

METHODS

Data from the Korean National Health Insurance Service identified 13,154,348 participants who underwent regular health checkups from 2005 to 2008. Subjects were classified according to status of diabetes mellitus (DM) and diabetic retinopathy (DR), and followed until the date of asthma development, death, or December 31, 2013. Cox proportional hazard regression analysis was used to evaluate the effect of diabetes, with or without retinopathy, on asthma development.

RESULTS

The incidences of asthma in the non-DM, DM without DR, and DR groups were 27.1, 30.1, and 38.4 per 1,000 person-years, respectively. Cox proportional hazard multiple regression models revealed that diabetic patients without retinopathy had a significantly lower risk of developing asthma than non-DM subjects (hazard ratio, 0.943; 95% confidence interval, 0.939-0.948). By contrast, diabetic patients with retinopathy had a higher risk of developing asthma (hazard ratio, 1.067; 95% confidence interval, 1.053-1.081).

CONCLUSION

Type 2 diabetes without retinopathy is not a risk factor for asthma development. However, patients with DR are at a greater risk of incident asthma, supporting the notion that the lung is a target organ for diabetic injury. Future studies will address whether proper glycemic control mitigates the risk of asthma.

Time trends of the prevalence of allergic diseases in Korea: A systematic literature review

The prevalence of allergic diseases has increased dramatically in recent decades, and are now considered major chronic diseases at the global level. The increasing burden of allergic diseases has led to numerous worldwide and local researchers to investigate the time trends in its prevalence and identify its driving factors. Environmental changes such as urbanization and industrialization have been suggested to explain the increasing prevalence, but recent reports from Western countries suggest that this prevalence has reached a plateau or even possibly, started to decrease. However, such environmental changes are still occurring in many Asia-Pacific countries, including Korea, and it is speculated that the peak in allergy epidemics has yet to come. The present systematic literature review aimed to explore the time trends in the prevalence of allergic diseases in Korea and to identify the unmet needs for facilitating further studies.

Prevalence of Self-reported Allergic Diseases and IgE Levels: A 2010 KNHANES Analysis

PURPOSE

The prevalence of allergic diseases is known to be associated with both demographic and environmental factors. Herein, we aimed to determine significant factors associated with the prevalence of allergic diseases and with total immunoglobulin E (tIgE) and specific immunoglobulin E (sIgE) levels in Korea.

METHODS

We analyzed unweighted data collected by the 2010 Korea National Health and Nutrition Examination Survey for 2,342 subjects who underwent serum tests for tIgE and sIgE to Dermatophagoides farinae, dog, and Blattella germanica, representing a sample of 16,003,645 citizens, by considering the sample weight and stratification.

RESULTS

The overall prevalence of self-reported allergic diseases was 37.6%. The prevalence rates of allergic rhinitis and atopic dermatitis decreased with age, whereas the asthma prevalence was not affected by the age of the subjects. When analyzed according to the type of allergic diseases, the prevalence of self-reported allergic disease was significantly associated with various factors (e.g. age, occupation, living in urban areas, and depression). The tIgE level decreased with age, but later increased. Elevation of tIgE was significantly associated with male sex, type of occupation, obesity, and smoking status. However, the risk factors for the increased sIgE levels to each allergen were quite different. Sensitization to D. farinae was more likely in young subjects, whereas the prevalence of sensitization to B. germanica was significantly higher in subjects with male sex, residing in a house (houses), and with glucose intolerance. Finally, young age and the smoking status were significantly associated with sensitization to dog.

CONCLUSIONS

Various demographic and environmental factors were significantly associated with the prevalence of self-reported allergic diseases and the levels of tIgE and sIgE to D. farinae, B. germanica, and dog in Korea.

The Need for a Well-Organized, Video-Assisted Asthma Education Program at Korean Primary Care Clinics

BACKGROUND

The purpose of this study was to assess the effect of our new video-assisted asthma education program on patients' knowledge regarding asthma and asthma control.

METHODS

Adult asthmatics who were diagnosed by primary care physicians and followed for at least 1 year were educated via smart devices and pamphlets. The education sessions were carried out three times at 2-week intervals. Each education period lasted at most 5 minutes. The effectiveness was then evaluated using questionnaires and an asthma control test (ACT).

RESULTS

The study enrolled 144 patients (mean age, 56.7±16.7 years). Half of the patients had not been taught how to use their inhalers. After participating in the education program, the participants' understanding of asthma improved significantly across all six items of a questionnaire assessing their general knowledge of asthma. The proportion of patients who made errors while manipulating their inhalers was reduced to less than 10%. The ACT score increased from 16.6±4.6 to 20.0±3.9 (p<0.001). The number of asthmatics whose ACT score was at least 20 increased from 45 (33.3%) to 93 (65.3%) (p<0.001). The magnitude of improvement in the ACT score did not differ between patients who received an education session at least three times within 1 year and those who had not. The majority of patients agreed to the need for an education program (95.8%) and showed a willingness to pay an additional cost for the education (81.9%).

CONCLUSION

This study indicated that our newly developed education program would become an effective component of asthma management in primary care clinics.

Asthma and the Risk of Rheumatoid Arthritis: An Insight into the Heterogeneity and Phenotypes of Asthma

Asthma is traditionally regarded as a chronic airway disease, and recent literature proves its heterogeneity, based on distinctive clusters or phenotypes of asthma. In defining such asthma clusters, the nature of comorbidity among patients with asthma is poorly understood, by assuming no causal relationship between asthma and other comorbid conditions, including both communicable and noncommunicable diseases. However, emerging evidence suggests that the status of asthma significantly affects the increased susceptibility of the patient to both communicable and noncommunicable diseases. Specifically, the impact of asthma on susceptibility to noncommunicable diseases such as chronic systemic inflammatory diseases (e.g., rheumatoid arthritis), may provide an important insight into asthma as a disease with systemic inflammatory features, a conceptual understanding between asthma and asthma-related comorbidity, and the potential implications on the therapeutic and preventive interventions for patients with asthma. This review discusses the currently under-recognized clinical and immunological phenotypes of asthma; specifically, a higher risk of developing a systemic inflammatory disease such as rheumatoid arthritis and their implications, on the conceptual understanding and management of asthma. Our discussion is divided into three parts: literature summary on the relationship between asthma and the risk of rheumatoid arthritis; potential mechanisms underlying the association; and implications on asthma management and research.

Health Care Utilization and Direct Costs in Mild, Moderate, and Severe Adult Asthma: A Descriptive Study Using the 2014 South Korean Health Insurance Database

PURPOSE

Although asthma exacerbation comprises a large burden of the total asthma-related costs, few studies have examined the frequency and cost of acute exacerbation according to asthma severity. This study investigated asthma-related health care utilization and costs according to the severity of asthma.

METHODS

We conducted a descriptive study using the national health insurance claims database between January 1 and December 31, 2014. We included adult patients with asthma (18 years of age and older) who had ≥2 claims with for an asthma diagnosis and were prescribed ≥1 asthma medications. They were classified into 3 asthma severity levels (level 1 = mild, level 2 = moderate, and level 3 = severe), based on individual medication prescriptions. Acute exacerbation was defined as having a corticosteroid burst, an emergency department visit, or hospitalization. Health care utilization, acute exacerbation, and direct costs associated with asthma were compared according to asthma severity levels.

FINDINGS

Of the 36,687 adult asthma patients, level 1 had the largest proportion of patients (81.2%), followed by level 2 (18.2%), and level 3 (0.6%). The average number of asthma-related outpatient visits was 4.5 for level 1, 7.2 for level 2, and 11.9 for level 3 (P < 0.01). The estimated asthma-related direct cost per patient was $174 for level 1, $634 for level 2, and $1635 for level 3 (P < 0.01). The number of patients who experienced acute exacerbation increased as asthma severity increased: level 1, 22.6%; level 2, 26.0%; and level 3, 48.7% (P < 0.01). Direct costs associated with asthma exacerbation dramatically increased and accounted for 15.1% of the total cost in level 1 patients, 19.5% in level 2 patients, and 40.8% in level 3 patients (P < 0.01).

IMPLICATIONS

The direct costs of acute exacerbation increased as asthma severity increased. In patients with severe asthma, acute exacerbation and the relative cost ratio in South Korea were higher than those in other countries. Proper management is required to avoid acute exacerbations and to reduce the burden of asthma, particularly in patients with severe asthma.

Inhaled Corticosteroids Use Is Not Associated With an Increased Risk of Pregnancy-Induced Hypertension and Gestational Diabetes Mellitus: Two Nested Case-Control Studies

There have been concerns that systemic corticosteroid use is associated with pregnancy-induced hypertension (PIH) and diabetes mellitus. However, the relationship between inhaled corticosteroids (ICSs) and the risk of PIH has not been fully examined, and there was no study investigating the association between ICS use and the development of gestational diabetes mellitus (GDM). The aims of the study are to determine whether the use of ICSs during pregnancy increases the risk of PIH and GDM in women.We conducted 2 nested case-control studies utilizing the nationwide insurance claims database of the Health Insurance Review and Assessment Service (Seoul, Republic of Korea), in which 1,306,281 pregnant women who delivered between January 1, 2009 and December 31, 2011 were included. Among them, PIH cases and GDM cases were identified and matched controls were included. Conditional logistic regression analyses adjusted by other concomitant drugs use during and before pregnancy and confounding covariates including comorbidities were performed.Total 43,908 PIH cases and 219,534 controls, and 34,190 GDM cases and 170,934 control subjects were identified. When other concomitant drugs use during pregnancy was adjusted, ICS use was associated with an increased rate of PIH (adjusted odds ratio, 1.40 [95% CI, 1.05-1.87]). ICS medication possession ratios and cumulative doses were associated with an increased risk of PIH. However, the statistical significance was not found in other models. In both unadjusted and adjusted multivariable models, ICSs use was not associated with increase in the risk of GDM.ICSs use is not associated with an increased risk of PIH and GDM.

Allergies are still on the rise? A 6-year nationwide population-based study in Korea

BACKGROUND

Some western countries recently have shown a slowdown in the incidence of allergic diseases after worldwide increasing trends, but there are few data from Asian populations concerning changing trend of allergic diseases. We evaluated the recent trends in the prevalence of asthma and other allergic diseases in Korea.

METHODS

From the database of Korean National Health Insurance, a nationwide diagnostic data from 2009 to 2014 were extracted and the national prevalence was analyzed.

RESULTS

The prevalence per 1000 people of atopic dermatitis, allergic rhinitis, and asthma in 2014 was 19.0, 133.1, and 36.3, respectively. The prevalence of three diseases was highest in the age group under 10 as, 95.0, 384.1, and 132.1 per 1000 people, while the prevalence in the over-10-year-group was only 11.6, 109.5, and 27.3, respectively. The prevalence of atopic dermatitis and allergic rhinitis gradually decreased with older age, but the prevalence of asthma showed a re-increasing pattern from the age group 30-39 and reached another peak for the age group 70-79. During the study period, the prevalence of asthma and atopic dermatitis showed decreasing tendency. In contrast, the prevalence of allergic rhinitis steadily increased until 2013, especially in the age group under 10.

CONCLUSIONS

The national prevalence of atopic dermatitis, and asthma did not show noticeable increase any more in Korea. However, the prevalence of allergic rhinitis still on the rise until recently, especially in the age group under 10. This is the first report in Asia suggesting a slowdown of the incidence of allergic diseases.

Association between inhaler use and risk of haemoptysis in patients with non-cystic fibrosis bronchiectasis

BACKGROUND AND OBJECTIVE

Inhaled medications have been widely applied to patients with airflow limiting non-cystic fibrosis (non-CF) bronchiectasis. However, the association between the use of inhalers and the development of haemoptysis has rarely been explored. The objective of this study was to assess the association between the risk of haemoptysis and the use of inhalers in patients with non-CF bronchiectasis.

METHODS

A nested case-control study was performed using a national claims database from 1 January 2009 to 31 December 2011. Inhalers including inhaled corticosteroids (ICS), long-acting β2 agonists (LABA), long-acting muscarinic antagonists (LAMA), short-acting β2 agonists (SABA), short-acting muscarinic antagonists (SAMA) and their combinations were tested for the risk of clinically significant haemoptysis events.

RESULTS

Among the 62 530 eligible new users of inhalers with non-CF bronchiectasis, 6180 patients with haemoptysis and 27 486 strictly matched controls were selected. In the unadjusted analyses, SAMA, LAMA, SABA and ICS/LABA significantly increased the risk of haemoptysis. After adjustment for other inhaled respiratory medications, comorbidities, health-care utilization and concomitant medications, SAMA, SABA and LAMA consistently increased the risk of haemoptysis (SAMA: odds ratio (OR), 1.6; 95% confidence interval (CI), 1.1-1.4; LAMA: OR, 1.2; 95% CI: 1.1-1.2; SABA: OR, 1.2; 95% CI: 1.1-1.2). The association between anticholinergics (SAMA and LAMA) and risk of haemoptysis showed a dose-dependent trend (P for trend, <0.001).

CONCLUSIONS

The use of SABA and inhaled anticholinergics in patients with non-CF bronchiectasis increased the risk of haemoptysis. The risk-benefit ratio of inhaled bronchodilators should be considered in the haemoptysis-susceptible population.

The Effect of Asthma Clinical Guideline for Adults on Inhaled Corticosteroids PrescriptionTrend: A Quasi-Experimental Study

In order to increase inhaled corticosteroid (ICS) use and to reduce hospitalization, emergency department visits and ultimately the economic burden of asthma, "Korean Asthma Management Guideline for Adults 2007" was developed. To assess the guideline effects on physician's ICS prescription for asthma, we conducted segmented regression and multilevel logistic regression using National Health Insurance claims database of outpatient visits from 2003 to 2010. We set each quarter of a year as a time unit and compared ICS prescription between before and after guideline dissemination. A total of 624,309 quarterly visits for asthma was observed. The ICS prescription rate before and after guideline dissemination was 13.3% and 16.4% respectively (P < 0.001). In the segmented regression, there was no significant guideline effect on overall ICS prescription rate. In multilevel logistic regression analyses, the effect of guideline on overall ICS prescription was not significant (odds ratio, 1.03; 95% CI, 1.00-1.06). In subgroup analysis, ICS prescription increased in secondary care hospitals (odds ratio, 1.15; 95% CI, 1.02-1.30) and in general hospitals (odds ratio, 1.10; 95% CI, 1.04-1.16). However, in primary clinics, which covered 81.7% of asthma cases, there was no significant change (odds ratio, 0.98; 95% CI, 0.94-1.02). From the in-depth interview, we could identify that the reimbursement criteria of the Health Insurance Review and Assessment Service and patient's preference for oral drug were barriers for the ICS prescription. The domestic asthma clinical guideline have no significant effect on ICS prescription, especially in primary clinics.