The association between inhaled long-acting bronchodilators and less in-hospital care in newly-diagnosed COPD patients

Effect of smoking on the development of chronic obstructive pulmonary disease in young individuals: a nationwide cohort study

Background

Cigarette smoking is an important risk factor for developing chronic obstructive pulmonary disease (COPD). However, the effect of smoking on the development of COPD in young individuals remains unclear. We aimed to evaluate the effect of smoking on COPD development in young individuals.

Methods

Using the Korean National Health Information Database, we screened individuals aged 20-39 years who participated in the national health check-up between 2009 and 2012. We defined physician-diagnosed COPD based on health insurance claims and searched the database until December 2019. We identified 6,307,576 eligible individuals, and 13,789 had newly developed COPD. We used multivariate Cox proportional hazards models to estimate the adjusted hazard ratio (aHR) of risk factors for COPD.

Results

The incidence rate for developing COPD was 0.26/1000 person-year. The risk of developing COPD was significantly higher in current smokers [aHR 1.46, 95% confidence interval (CI) 1.39-1.53] and former smokers (aHR 1.21, 95% CI 1.14-1.29) than in non-smokers. Furthermore, the risk increased with increasing smoking amounts (≥20 pack-years, aHR 2.24; 10-20 pack-years, aHR 1.55; <10 pack-years, aHR 1.27). Female participants had a higher relative risk of developing COPD due to smoking, compared with their male counterparts.

Conclusion

Cigarette smoking increased the risk of developing COPD in young individuals. Current and heavy smokers had higher risks of developing COPD than non-smokers. Female smokers were more likely to develop COPD than male smokers.

Smoking cessation after diagnosis of COPD is associated with lower all-cause and cause-specific mortality: a nationwide population-based cohort study of South Korean men

BACKGROUND

The most effective way to halt the advancement of COPD is smoking cessation. However, limited data are available on the question of whether quitting smoking within two years after COPD diagnosis reduces the risk of mortality. The goal of our research was to analyze the relationship between quitting smoking after COPD diagnosis and the risks of all-cause and cause-specific mortality, using the Korean National Health Insurance Service (NHIS) database.

METHODS

This study included 1,740 male COPD patients aged 40 years or more who had been newly diagnosed within the 2003-2014 time period and had smoked prior to their COPD diagnosis. The patients were categorized into two groups according to their smoking status after COPD diagnosis: (i) persistent smokers (ii) quitters (smoking cessation within two years of COPD diagnosis). Multivariate Cox proportional hazard regression was performed to determine the adjusted hazard ratio (HR) and 95% confidence interval (CI) for both all-cause and cause-specific mortality.

RESULTS

Among 1,740 patients (mean age, 64.6 years; mean follow-up duration, 7.6 years), 30.5% stopped smoking after COPD diagnosis. Quitters gained a 17% risk reduction in all-cause mortality (aHR, 0.83; 95% CI, 0.69-1.00) and a 44% risk reduction in cardiovascular mortality (aHR, 0.56; 95% CI, 0.33-0.95) compared with persistent smokers.

CONCLUSION

Our study found that patients who quit smoking within two years after COPD diagnosis had lower risks of all-cause and cardiovascular mortality relative to persistent smokers. These results can be used to encourage newly diagnosed COPD patients to stop smoking.

Short-Term Air Pollution Exposure and Risk of Acute Exacerbation of Chronic Obstructive Pulmonary Disease in Korea: A National Time-Stratified Case-Crossover Study

We investigated the association between short-term exposure to air pollution and the risk of acute exacerbation of chronic obstructive pulmonary disease (AE-COPD) in seven metropolitan cities in Korea. We used national health insurance claims data to identify AE-COPD cases in 2015. We estimated short-term exposure to particulate matter (PM) with a diameter of ≤2.5 μm (PM_2.5), PM with diameters of ≤10 μm (PM₁₀), sulfur dioxide (SO₂), nitrogen dioxide (NO₂), carbon monoxide (CO), and ozone (O₃) obtained from the Ministry of Environment. We conducted a time-stratified, case-crossover study to evaluate the effect of short-term exposure to air pollution on hospital visits for AE-COPD, using a conditional logistic regression model. The risk of hospital visits for AE-COPD was significantly associated with interquartile range increases in PM₁₀ in a cumulative lag model (lag 0–2, 0.35%, 95% confidence interval (CI) 0.06–0.65%; lag 0–3, 0.39%, 95% CI 0.01–0.77%). The associations were higher among patients who were men, aged 40–64 years, with low household income, and with a history of asthma. However, other air pollutants were not significantly associated with the risk of hospital visits for AE-COPD. Short-term exposure to air pollution, especially PM₁₀, increases the risk of hospital visits for AE-COPD.

The current status of chronic obstructive pulmonary disease awareness, treatments, and plans for improvement in South Korea: a narrative review

The prevalence of chronic obstructive pulmonary disease (COPD) is high in South Korea which has remained virtually unchanged over the past few years. Other challenges related to COPD in South Korea include a low level of awareness of COPD, underutilization of pulmonary function tests (PFTs) and a low level of inhaler use. Continued efforts have been made to raise awareness of COPD in the general public and promote screening tests for the early detection of COPD patients for high-risk patients, which should be the primary object for better management of the disease. The Korean Academy of Tuberculosis and Respiratory Diseases (KATRD) and the Korea Disease Control and Prevention Agency (KDCA) have been working in tandem on numerous projects to resolve these issues. As the fruit of these efforts, a couple of projects are currently being carried out to add PFTs into the National Health Examination (NHE) of Korea as part of screening tests and improve the quality of COPD treatments in primary care settings. Raising public awareness of a chronic disease such as COPD requires collective efforts of academic societies and government. In addition, personalized education programs that are tailored to individual COPD patients is a necessity to raise adherence of treatment and self-management of COPD. The aim of this manuscript is to report the current status of COPD management in South Korea in hopes that it will help better treat and manage COPD in other nations coping with similar challenges.

Clinical Characterization of Nursing Facility Residents With Chronic Obstructive Pulmonary Disease

OBJECTIVE AND DESIGN

To describe clinical characteristics, medication use, and low peak inspiratory flow rate (PIFR) (< 60 L/min) prevalence in nursing facility residents with chronic obstructive pulmonary disease (COPD).

PATIENTS AND SETTING

Residents 60 years of age and older with a COPD diagnosis and≥ 6 months' nursing facility residence, were enrolled between December 2017 and February 2019 from 26 geographically varied United States nursing facilities.

OUTCOME MEASURES

Data, extracted from residents' charts, included demographic/clinical characteristics, COPD-related medications, exacerbations and hospitalizations within the past 6 months, and functional status from the most recent Minimum Data Set. At enrollment, residents completed the modified Medical Research Council (mMRC) Dyspnea Scale and COPD Assessment Test (CAT™). Spirometry and PIFR were also assessed.

RESULTS

Residents' (N = 179) mean age was 78.0 ± 10.6 years, 63.7% were female, and 57.0% had low PIFR. Most prevalent comorbidities were hypertension (79.9%), depression (49.2%), and heart failure (41.9%). The average forced expiratory volume in 1 second (FEV1₁) % predicted was 45.9% ± 20.9%. On the CAT, 78.2% scored≥ 10 and on the mMRC Dyspnea Scale, 74.1% scored≥ 2, indicating most residents had high COPD symptom burden. Only 49.2% were receiving a scheduled long-acting bronchodilator (LABD). Among those with low PIFR prescribed a LABD, > 80% used dry powder inhalers for medication delivery.

CONCLUSION

This study highlights underutilization of scheduled LABD therapy in nursing facility residents with COPD. Low PIFR was prevalent in residents while the majority used suboptimal medication delivery devices. The findings highlight opportunities for improving management and outcomes for nursing facility residents with COPD.

Nationwide quality assessment of treatment for chronic obstructive pulmonary disease

Background

Chronic obstructive pulmonary disease (COPD) requires careful ambulatory care. If treatment is effective, exacerbation and hospitalization can be preventable. Appropriate management is important; the disease prevalence is high, as is the demand on healthcare resources. Here, we have reported the results of nationwide quality assessment performed with the aims of improving patient management, reducing progression to severe status, and minimizing medical care expenses.

Methods

The Health Insurance Review and Assessment Service (HIRA) engaged in quality assessment three times from May 2014 to April 2017. Medical care institutions were evaluated in terms of the pulmonary function test (PFT), patient revisit, and inhaled bronchodilator prescription rates.

Results

The numbers of patients assessed were 141,782, 142,790, and 143,339 in years 1, 2, and 3, respectively; the numbers of medical care institutions assessed were 6,691, 6,722, and 6,470, respectively. The PFT implementation rates were 58.7%, 62.5%, and 67.9% for years 1, 2, and 3, respectively; these rates were highest for tertiary hospitals, followed by general and local hospitals, as well as primary healthcare clinics. The repeat visit rates were 85.5%, 92.1%, and 85.0% for years 1, 2, and 3, respectively; these rates were highest for general hospitals, followed by local and tertiary hospitals, and primary healthcare clinics. The inhaled bronchodilator prescription rates were 67.9%, 71.2%, and 76.9% for years 1, 2, and 3, respectively; these rates increased with increasing hospital grade.

Conclusions

The PFT and inhaled bronchodilator prescription rates improved over the 3-year nationwide quality assessment period.

Relationship Between Changes in Inhalation Treatment Level and Exacerbation of Chronic Obstructive Pulmonary Disease: Nationwide the Health Insurance and Assessment Service Database

Background and Objective

Maintaining adequacy in chronic obstructive pulmonary disease (COPD) care is essential to sustain an adequate level of care. We aimed to assess the current status of COPD quality control and the influence of inhaler changes on disease-related health care utilization.

Methods

The Health Insurance Review and Assessment Service (HIRA) nationwide database for reimbursed insurance claims from all medical institutions in South Korea from May 2014 to April 2017 was investigated. COPD care quality was assessed by the performance rate of spirometry, the percentage of persistent visit patients and patients prescribed a bronchodilator. The number of severe exacerbations was evaluated.

Results

A total of 68,942 COPD patients were included for 3 years of longitudinal analyses. The overall spirometry enforcement rate was just over 50%, the percentage of regular follow-up patients was over 85%, and bronchodilators were prescribed to over 80% of the patients. COPD-related hospitalization or ER visit rates were 16.6%, 15.3%, and 17.8% for three consequent assessments, respectively. Inhaler changes were analyzed between the first and second assessments: 57.1% were maintained, 0.4% were changed to another class, 9% were escalated, and 5.2% were de-escalated. Only in the escalated group, especially those who changed from the mono to dual inhaler and dual to triple inhaler, had fewer hospitalizations or ER visits.

Conclusion

Adequacy of COPD care status was not that high considering the low-enforcement rate of spirometry, but most patients were prescribed a bronchodilator and regularly followed up. Those who escalated inhaler treatment experienced less health care utilization.

Mortality of patients with chronic obstructive pulmonary disease: a nationwide populationbased cohort study

BACKGROUND/AIMS

Chronic obstructive pulmonary disease (COPD) is a major cause of mortality in the world. There are no population-based studies on longterm mortality in COPD patients in Korea.

METHODS

Using the large, population-based, National Health Insurance Service- National Sample Cohort (NHIS-NSC), we identified COPD patients using the International Classification of Disease-Tenth Revision (ICD-10) and prescription details in the NHIS-NSC during 2003 to 2013. We analyzed the survival curves of COPD patients by sex, age, and cause of death.

RESULTS

A total of 14,127 individuals older than 40 years were diagnosed with COPD. There were a total of 3,695 deaths (26.2%) in COPD patients during the study period. The 5-year mortality of COPD patients was 25.4% (29.9% in males and 19.1% in females). The mortality rate increased rapidly with age. The most common cause of death in COPD was chronic lower respiratory disease.

CONCLUSION

This study described long-term mortality in COPD patients in Korea. Higher mortality was observed in males, and it was closely related to age.

Does Changing Inhaler Device Impact Real-Life Asthma Outcomes? Clinical and Economic Evaluation

BACKGROUND

Inhaler usability and deposition differ between devices. Change of device may therefore have an impact on clinical and economic outcomes.

OBJECTIVE

To characterize clinical and economic asthma outcomes surrounding the change from a dry powder inhaler (DPI) to a pressurized metered-dose inhaler (pMDI) for fixed-dose combination inhaled corticosteroid/long-acting β agonist (FDC ICS/LABA) treatment.

METHODS

Three retrospective cohort substudies using 2010 to 2015 data from the Korean Health Insurance and Review Assessment Service database were performed. Patients with asthma who received an FDC ICS/LABA pMDI for the first time after initially being on FDC ICS/LABA DPI were included. The following outcomes were assessed: (1) persistence of change to pMDI over 6 months, (2) clinical outcomes during the year after the change compared with the baseline year; and (3) noninferiority comparison of costs and effectiveness between patients changing to a pMDI and matched patients who continued their DPI.

RESULTS

Patients who change inhalers seem to represent a more severe subpopulation. Fifty-eight percent of patients (95% CI, 56-60) persisted with the change. After the change in therapy, an increased proportion of patients (58.3%) remained free from severe exacerbations compared with the year before (47.4%; P < .001). Patients who changed to pMDIs had significantly less severe exacerbations, acute respiratory events, and lower short-acting β agonist inhaler average daily dose, but higher average ICS daily dose (all P < .05), compared with matched patients remaining on a DPI. Total costs were similar between patients who changed to pMDI therapy compared with those remaining on a DPI.

CONCLUSION

Changing from a DPI to a pMDI for FDC ICS/LABA asthma treatment can be as effective and cost-effective as remaining on a DPI.

Hemoglobin and mortality in patients with COPD: a nationwide population-based cohort study

Purpose

Previous studies have reported that anemia increased mortality in patients with COPD. However, it is unclear whether anemia is associated with increased COPD mortality in the general population. The purpose of our study is to identify whether anemia is related to long-term mortality in COPD using a large population-based database.

Patients and methods

Using the National Health Insurance Service-Health Screening Cohort, we identified COPD patients with available hemoglobin level. We analyzed mortality among patients with COPD from 2003 to 2013 according to hemoglobin level.

Results

A total of 7,114 patients with COPD were identified. Mean age was 65.0±9.3 years, and 62.9% were male. Anemia was present in 469 patients (6.6%). The overall mortality rate was 46.5% in anemia and 32.1% in non-anemia groups (p<0.001). The hazard ratio of anemia for mortality was 1.31 (95% CI, 1.11–1.54). Among patients with anemia, the hemoglobin level correlated well with mortality.

Conclusion

Anemia was associated with increased long-term mortality of COPD, and even mild anemia was related to a significantly increased risk.

Efficacy of tiotropium/olodaterol on lung volume, exercise capacity, and physical activity

Purpose

This study evaluated the efficacy of tiotropium/olodaterol vs tiotropium on lung function, exercise capacity, and physical activity in patients with COPD.

Patients and methods

A total of 184 patients aged ≥40 years with COPD (Global Initiative for Chronic Obstructive Lung Disease stage II-IV) received tiotropium/olodaterol for 6 weeks, then tiotropium for 6 weeks, or vice versa. The primary endpoint was inspiratory capacity (IC) at peak post-dose.

Results

Adjusted mean IC after 6-week treatment was 1.990 L with tiotropium/olodaterol vs 1.875 L with tiotropium (difference: 115 mL; 95% CI: 77, 153; p<0.0001). Forced expiratory volume in 1 s (difference: 105 mL; 95% CI: 88, 123), forced vital capacity (difference: 163 mL; 95% CI: 130, 197), and slow vital capacity (difference: 134 mL; 95% CI: 91, 176) improved with tiotropium/olodaterol (all p<0.0001). Adjusted mean 6-min walk distance was similar between treatments in the overall population but was significantly increased with tiotropium/olodaterol in the subgroup with Global Initiative for Chronic Obstructive Lung Disease stage III/IV at baseline (difference: 18.1 m; 95% CI: 2.3, 33.9; p=0.0254). In a post hoc analysis, tiotropium/olodaterol improved the values for ≥2.0 metabolic equivalents (difference: 5.0 min; 95% CI: 0.4, 9.7; p=0.0337).

Conclusion

Tiotropium/olodaterol significantly improved IC compared with tiotropium and potentially enhanced the exercise capacity in COPD patients. A slight improvement in physical activity of relatively more than moderate intensity was also seen with tiotropium/olodaterol.

Comparison of the in vitro pharmacological profiles of long-acting muscarinic antagonists in human bronchus

BACKGROUND AND PURPOSE

Long-acting muscarinic antagonists (LAMAs) have been recommended for the treatment of chronic obstructive pulmonary disease and (more recently) asthma. However, the in vitro pharmacological profiles of the four LAMAs currently marketed (tiotropium, umeclidinium, aclidinium and glycopyrronium) have not yet been compared (relative to ipratropium) by using the same experimental approach.

EXPERIMENTAL APPROACH

With a total of 560 human bronchial rings, we investigated the antagonists' potency, onset and duration of action for inhibition of the contractile response evoked by electrical field stimulation. We also evaluated the antagonists' potency for inhibiting cumulative concentration-contraction curves for acetylcholine and carbachol.

KEY RESULTS

The onset and duration of action were concentration-dependent. At submaximal, equipotent concentrations, the antagonists' onsets of action were within the same order of magnitude. However, the durations of action differed markedly. After washout, ipratropium's inhibitory activity decreased rapidly (within 30-90 min) but those of tiotropium and umeclidinium remained stable (at above 70%) for at least 9 h. Aclidinium and glycopyrronium displayed less stable inhibitory effects, with a progressive loss of inhibition at submaximal concentrations. In contrast to ipratropium, all the LAMAs behaved as insurmountable antagonists by decreasing the maximum responses to both acetylcholine and carbachol.

CONCLUSIONS AND IMPLICATIONS

The observed differences in the LAMAs' in vitro pharmacological profiles in the human bronchus provide a compelling pharmacological rationale for the differences in the drugs' respective recommended daily doses and frequencies of administration.

Comparative study on medical utilization and costs of chronic obstructive pulmonary disease with good lung function

Introduction

Patients with mild to moderate chronic obstructive pulmonary disease (COPD) are underdiagnosed and undertreated due to the asymptomatic nature of the disease. Previous studies on patients with mild COPD have focused on symptomatic patients. Therefore, in this study, we evaluated the treatment status of patients with early COPD in Korea.

Materials and methods

We compared hospital visits, medical costs per person, and COPD medication use by patients with COPD screened from the general population and COPD cohort patients. Patients with COPD aged ≥40 years with the value of forced expiratory volume in 1 s (FEV₁) ≥60% were selected from the 2007 to 2012 Korea National Health and Nutrition Examination Survey (KNHANES) data. Data including the number of outpatient clinic visits, admission to hospitals, COPD-related medications, and medical costs were obtained from the Health Insurance Review and Assessment Service and were compared with the data of patients with COPD with FEV₁ ≥60% from the Korean COPD Subtype Study (KOCOSS) cohort.

Results

Based on EuroQol 5-dimension questionnaire index scores of 0.9±0.14, we found that patients with COPD from the KNHANES group showed few symptoms compared to those from the KOCOSS cohort. In 2007, among the patients with COPD with an FEV₁ value of ≥60%, only 3.6% from the KNHANES group and 30% from the KOCOSS cohort visited medical facilities. Total medical cost per person per year increased from 264.37±663.41 US Dollars (USD) in 2007 to 797.00±2,724.21 USD in 2012 for the KNHANES group. In 2012, only 20.7% of the patients from KNHANES database received long-acting muscarinic agonists (LAMA), whereas 78.7% of the patients from KOCOSS database received LAMA.

Conclusion

Medical resource utilization and medical costs per person for patients with early COPD in Korea increased. However, asymptomatic patients with COPD represented by the KNHANES group do not receive adequate long-term treatment compared to relatively symptomatic patients, and require more clinical attention from physicians.

Effects of inhaled corticosteroids /long-acting agonists in a single inhaler versus inhaled corticosteroids alone on all-cause mortality, pneumonia, and fracture in chronic obstructive pulmonary disease: A nationwide cohort study 2002-2013

BACKGROUND

Both inhaled corticosteroids (ICS) and long-acting ?-agonists (LABA) have been recommended for the treatment of severe/moderate chronic obstructive pulmonary disease (COPD), but mild COPD has not been frequently studied.

METHODS

We performed a prospective cohort study to compare the effect of inhaled corticosteroid (ICS) and ICS/long-acting ?-agonist (LABA) in a single inhaler on all-cause mortality and adverse events, such as pneumonia and fracture, in patients with newly diagnosed chronic obstructive pulmonary disease (COPD). We used representative nationwide cohort data from the Korean National Health Insurance claims database (2002-2013). Patients who were at least 40-years-old, newly diagnosed with COPD, and prescribed ICS or ICS/LABA in a single inhaler (N = 1995). To analyze the data, we utilized a Cox's proportional hazard regression.

RESULTS

Among the total of 1995 patients, 807 had severe COPD (FEV₁ < 50%) and 1188 had mild/moderate COPD (FEV₁ ? 50%). The cumulative incidence and 5-year cumulative incidence of all-cause mortality was 59.5% and 29.6% for ICS users, and 35.8% and 20.2% for single inhaler ICS/LABA users, respectively. The adjusted hazard ratio (HR) of all-cause mortality for new ICS/LABA users, compared with that in new ICS users, was 0.77 (95% CI: 0.62-0.95) for the total population. For the severe and non-severe COPD groups, the adjusted HRs of all-cause mortality for new ICS/LABA users were 1.07 (95% CI: 0.65-1.76) and 0.70 (95% CI: 0.55-0.89), respectively. There was no difference in the risk for the first hospitalization due to pneumonia between new ICS and ICS/LABA users among the total population (HR: 1.02; 95% CI: 0.79-1.34). The adjusted HR of the first hospitalization for fractures in new ICS/LABA users, compared with that in new ICS users, was 0.60 (95% CI: 0.39-0.92) for the total population.

CONCLUSIONS

Among newly diagnosed COPD patients and new users of ICS or ICS/LABA, use of ICS/LABA in a single inhaler was associated with lowered risk of all-cause mortality and delayed first hospitalization for fracture, as compared with use of ICS alone. However, there was no significant difference in terms of first hospitalization for pneumonia.

Towards Actualizing the Value Potential of Korea Health Insurance Review and Assessment (HIRA) Data as a Resource for Health Research: Strengths, Limitations, Applications, and Strategies for Optimal Use of HIRA Data

Health Insurance and Review Assessment (HIRA) in South Korea, also called National Health Insurance (NHI) data, is a repository of claims data collected in the process of reimbursing healthcare providers. Under the universal coverage system, having fee-for-services covering all citizens in South Korea, HIRA contains comprehensive and rich information pertaining to healthcare services such as treatments, pharmaceuticals, procedures, and diagnoses for almost 50 million beneficiaries. This corpus of HIRA data, which constitutes a large repository of data in the healthcare sector, has enormous potential to create value in several ways: enhancing the efficiency of the healthcare delivery system without compromising quality of care; adding supporting evidence for a given intervention; and providing the information needed to prevent (or monitor) adverse events. In order to actualize this potential, HIRA data need to actively be utilized for research. Thus understanding this data would greatly enhance this potential. We introduce HIRA data as an important source for health research and provide guidelines for researchers who are currently utilizing HIRA, or interested in doing so, to answer their research questions. We present the characteristics and structure of HIRA data. We discuss strengths and limitations that should be considered in conducting research with HIRA data and suggest strategies for optimal utilization of HIRA data by reviewing published research using HIRA data.

Effects of individual and neighborhood socioeconomic status on the risk of all-cause mortality in chronic obstructive pulmonary disease: A nationwide population-based cohort study, 2002-2013

BACKGROUND

Numerous previous studies have shown that individual socioeconomic status (SES) is associated with mortality in patients with chronic obstructive pulmonary disease (COPD), but few empirical studies have evaluated the effects of individual SES and neighborhood deprivation on mortality in COPD patients.

METHODS

We performed a prospective cohort study to examine the effect of socioeconomic disparity on all-cause mortality in newly diagnosed COPD patients in a setting with universal health care coverage. We used representative population-based nationwide cohort data from the Korean National Health Insurance claims database (2002-2013). We included patients who were at least 40 years old and newly diagnosed with COPD (N = 9275). To analyze the data, we utilized a frailty model and Cox's proportional hazard regression.

RESULTS

A total of 1849 (19.9%) of the 9275 eligible participants died during the study period. Compared to high-income patients from advantaged neighborhoods, the adjusted hazard ratio (HR) for middle-income COPD patients who lived in advantaged and disadvantaged neighborhoods was 1.22 (95% CI, 1.03-1.43) and 1.36 (95% CI, 1.15-1.60), respectively. For low-income patients, the adjusted HR for patients who lived in disadvantaged neighborhoods was higher than for patients who lived in advantaged neighborhoods (HR, 1.43; 95% CI, 1.17-1.74 vs. HR, 1.36; 95% CI, 1.11-1.66). There was no difference in the adjusted HRs for high-income patients who lived in advantaged and disadvantaged neighborhoods (HR, 1.01; 95% CI, 0.84-1.22).

CONCLUSIONS

Socioeconomic disparity contributes to all-cause mortality in COPD patients and neighborhood deprivation exacerbates the effect of individual SES on all-cause mortality in COPD patients.

Home oxygen therapy reduces risk of hospitalisation in patients with chronic obstructive pulmonary disease: a population-based retrospective cohort study, 2005-2012

OBJECTIVE

This study evaluated the effect of home oxygen therapy (HOT) on hospital admissions in chronic obstructive pulmonary disease (COPD) patients.

DESIGN AND SETTING

Using nationwide health insurance claims from 2002-2012, we conducted a longitudinal population-based retrospective cohort study.

PARTICIPANTS

Individuals who were aged 40 years or above and newly diagnosed with COPD in 2005.

OUTCOME MEASURES

The primary outcome was total number of hospitalisations during the study period. Participants were matched using HOT propensity scores and were stratified by respiratory impairment (grade 1: FEV1 ≤25% or PaO2 ≤55 mm Hg; grade 2: FEV1 ≤30% or PaO2 56-60 mm Hg; grade 3: FEV1 ≤40% or PaO2 61-65 mm Hg; 'no grade': FEV1 or PaO2 unknown), then a negative binomial regression analysis was performed for each group.

RESULTS

Of the 36,761 COPD patients included in our study, 1330 (3.6%) received HOT. In a multivariate analysis of grade 1 patients performed before propensity score matching, the adjusted relative risk of hospitalisation for patients who did not receive HOT was 1.27 (95% CI 1.01 to 1.60). In a multivariate analysis of grade 1 patients performed after matching, the adjusted relative risk for patients who did not receive HOT was 1.65 (95% CI 1.25 to 2.18). In grade 2 or grade 3 patients, no statistical difference in hospital admission risk was detected. In the 'no grade' group of patients, HOT was associated with an increased risk of hospitalisation.

CONCLUSIONS

HOT reduces the risk of hospital admission in COPD patients with severe hypoxaemia. However, apart from these patients, HOT use is not associated with hospital admissions.

A guide for the utilization of Health Insurance Review and Assessment Service National Patient Samples

The claims data of the Health Insurance Review and Assessment Service (HIRA) is an important source of information for healthcare service research. The claims data of HIRA is collected when healthcare service providers submit a claim to HIRA to be reimbursed for a service that they provided to patients. To improve the accessibility of healthcare service researchers to claims data of HIRA, HIRA has developed the Patient Samples which are extracted using a stratified randomized sampling method. The Patient Samples of HIRA consist of five tables: a table for general information (Table 20) containing socio-demographic information such as gender, age and medical aid, indicators for inpatient and outpatient services; a table for specific information on healthcare services provided (Table 30); a table for diagnostic information (Table 40); a table for outpatient prescriptions (Table 53) and a table for information on healthcare service providers (Table of providers). Researchers who are interested in using the Patient Sample data for research can apply via HIRA's website (https://www.hira.or.kr).