Narrative review of current COPD status in Japan

Much lower prevalence and mortality of chronic obstructive pulmonary disease in Japan than in the US despite higher smoking rates: A meta analysis/systematic review

BACKGROUND

A recent systematic review showed Japan's mortality from chronic obstructive pulmonary disease (COPD) is the lowest among 204 countries, despite notably higher smoking rates in men in Japan than in the US. This study aims to compare (1) trends in smoking rates, (2) trends in COPD mortality, and (3) the spirometry-based COPD prevalence in the general adult population between Japan and the US.

METHODS

Age- and sex-specific smoking rates from the 1980s through 2010s and COPD mortality from 1999 through 2019 were obtained from national surveys and official statistics (International Classification of Diseases-10th codes J40-44), respectively. A systematic review and meta-analysis was performed to estimate COPD prevalence in Japan, while the National Health and Nutrition Examination Survey 2007-2012 was used for the US. A fixed ratio of 0.7 of forced expiratory volume in the first second of forced vital capacity was used to define COPD.

RESULTS

Over the past four decades, men in Japan consistently had 20-30% higher smoking rates than their US counterparts. From 1999-2019, age-adjusted COPD mortality in men in Japan was only a third of the US, whereas that in women was less than a tenth in 2019. Synthesizing data from 11 studies, involving 89,955 participants, Japan's COPD prevalence was more than 10% lower than in the US in almost all age groups for both sexes.

CONCLUSIONS

This study showed markedly lower rates of COPD in Japan than in the US. Investigating factors contributing to the paradoxical observations could lead to advancing COPD risk reduction strategies.

Nontuberculous mycobacterial pulmonary disease added burden to COPD and bronchiectasis in Japan

Background and objective

Nontuberculous mycobacterial pulmonary disease (NTM-PD) prevalence in Japan is among the highest worldwide. COPD and bronchiectasis are common comorbidities among patients with NTM-PD, and it is challenging to treat NTM-PD in patients with these conditions. There are limited data on the incremental burden that NTM-PD adds to underlying COPD or bronchiectasis in Japan. Therefore, the objective of this study was to assess the incremental burden associated with NTM-PD in patients with pre-existing COPD and/or bronchiectasis.

Methods

This nested case-control study was based on JMDC, Inc. claims data (2015-2020). Patients with COPD and/or bronchiectasis with NTM-PD (cases) were age and sex matched 1:3 to patients with COPD and/or bronchiectasis without NTM-PD (controls), resulting in three mutually exclusive patient groups (COPD, bronchiectasis or both; with or without NTM-PD). Incremental burden of NTM-PD was assessed within each group by comparing hospitalisations during the 1-year period after NTM-PD diagnosis (index) between cases and controls with both univariate analysis and multivariate analysis adjusting for pre-index comorbidities.

Results

Univariate analyses in the three patient groups consistently demonstrated incremental hospitalisation burden in cases versus controls (e.g. COPD group: 20% of 492 cases versus 13% of 1476 controls had all-cause hospitalisations; 11% versus 5% had respiratory-related hospitalisations; and 6% versus 2% had COPD-related hospitalisations). Subsequent multivariate analysis further confirmed the findings.

Conclusions

The substantial incremental burden of hospitalisation associated with NTM-PD in patients with COPD and/or bronchiectasis highlights the urgent need for appropriate management of NTM-PD in Japan.

Association of Frailty with Patient-Report Outcomes and Major Clinical Determinants in Patients with Acute Exacerbation of Chronic Obstructive Pulmonary Disease

Purpose

This study aimed to explore the correlation of frailty status with disease characteristics and patient-reported outcomes (PROs) in patients with acute exacerbations of chronic obstructive pulmonary disease (AECOPD) and determine the sensitivity and specificity of modified COPD PRO scale (mCOPD-PRO) for detecting frailty.

Patients and Methods

This cross-sectional study surveyed 315 inpatients with AECOPD from a tertiary hospital in China from August 2022 to June 2023. Patient frailty and PROs were assessed using the validated FRAIL scale and mCOPD-PRO, respectively. Spearman's ρ was used to assess the relevance of lung disease indicators commonly used in clinical practice, and ordinal logistic regression analyses were used to identify the variables associated with frailty status. The validity of mCOPD-PRO in discriminating frail or non-frail individuals was determined using the receiver operating characteristic curve.

Results

The participants (N=302, mean age 72.4±9.1 years) were predominantly males (73.2%). Among them, 43 (14.3%) patients were not frail, whereas 123 (40.7%) and 136 (45.0%) patients were pre-frail and frail, respectively. The FRAIL scale was moderately correlated with the mCOPD-PRO scores (Spearman's rank correlation coefficient [Rs]=0.52, P<0.01) for all dimensions (Rs=0.43-0.49, P<0.01). Patients residing in rural areas (odds ratio [OR], 1.67; 95% confidence interval [95% CI], 1.01-2.76) and with higher mCOPD-PRO scores (OR, 4.78; 95% CI, 2.75-8.32) were more likely to be frail. Physically active patients (OR, 0.42; 95% CI, 0.21-0.84) were less likely to be frail. In addition, mCOPD-PRO had good discriminate validity for detecting frailty (area under the curve=0.78), with a sensitivity and specificity of 84.6% and 60.8%, respectively. The optimal probability threshold for mCOPD-PRO was ≥1.52 points.

Conclusion

In patients with AECOPD, frailty is closely related to PROs and disease characteristics. Additionally, the mCOPD-PRO score can distinguish well between frail and non-frail patients. Our findings provide support for interventions targeting frail populations with AECOPD.

Impact of the COVID-19 pandemic on COPD exacerbations in Japanese patients: a retrospective study

Various infection control measures implemented during the coronavirus disease (COVID-19) pandemic have reduced the number of respiratory infections, which are the most common cause of chronic obstructive pulmonary disease (COPD) exacerbations. Here, we investigated whether infectious disease prevention during the COVID-19 pandemic reduced COPD exacerbations and the characteristics of patients exhibiting exacerbations before and during the COVID-19 pandemic. We included outpatients and inpatients with moderate or severe COPD exacerbations who required systemic steroids between April 1, 2018 and March 31, 2022. Their medical records were retrospectively compared and analyzed in 2-year intervals (before and during the COVID-19 pandemic). During the 4-year observation period, 70,847 outpatients and 2,772 inpatients were enrolled; 55 COPD exacerbations were recorded. The number of COPD exacerbations decreased from 36 before to 19 during the COVID-19 pandemic. Regarding the characteristics of patients with exacerbations, the % forced expiratory volume in one second (52.3% vs. 38.6%, P = 0.0224) and body mass index (BMI) (22.5 vs. 19.3, P = 0.0127) were significantly lower during the COVID-19 pandemic than before the pandemic. The number of COPD exacerbations during the pandemic decreased. Additionally, the tendency for a reduction in COPD exacerbation was greatest in patients with preserved lung function or above-standard BMI patients.

Prevalence and risk factors of frailty in patients with chronic obstructive pulmonary disease: systematic review and meta-analysis

OBJECTIVE

To systematically review the prevalence and risk factors for frailty in patients with chronic obstructive pulmonary disease (COPD).

METHODS

A systematic review and meta-analysis were conducted, and a search of the PubMed, Embase and Web of Science databases was carried out to collect Chinese and English studies on frailty and COPD published up to September 5, 2022.

RESULTS

A total of 38 articles were included for the quantitative analysis after the collected literature was either included or omitted based on pertinent criteria. The results indicated that the estimated overall pooled prevalence of frailty was 36% (95% confidence interval [CI] = 31-41%), and the estimated pre-frailty was 43% (95% CI = 37-49%). A higher age (odds ratio [OR] = 1.04; 95% CI = 1.01-1.06) and higher COPD assessment test (CAT) score (OR = 1.19; 95% CI = 1.12-1.27) were associated with a significantly increased likelihood of frailty in patients with COPD. However, a higher educational attainment (OR = 0.55; 95% CI = 0.43-0.69) and higher income (OR = 0.63; 95% CI = 0.45-0.88) were associated with a significantly reduced risk of frailty in patients with COPD. A total of 17 other risk factors for frailty were identified via qualitative synthesis.

CONCLUSION

The incidence of frailty in patients with COPD is high, and there are many influencing factors.

Recent Prevalence of and Factors Associated With Chronic Obstructive Pulmonary Disease in a Rapidly Aging Society: Korea National Health and Nutrition Examination Survey 2015-2019

BACKGROUND

The prevalence of chronic obstructive pulmonary disease (COPD) increases with age, and aging is an important risk factor for COPD development. In the era of global aging, demographic information about the prevalence of and factors associated with COPD are important to establish COPD care plans. However, limited information is available in rapidly aging societies, including Korea.

METHODS

We conducted a cross-sectional observational study using Korea National Health and Nutrition Examination Survey data from 2015-2019. We included 15,613 participants and analyzed trends of and factors associated with COPD.

RESULTS

During the study period, the overall prevalence of COPD was 12.9%. Over five years, the yearly prevalence of COPD was fairly constant, ranging from 11.5% to 13.6%. Among individuals aged ≥ 70 years, nearly one-third met COPD diagnostic criteria. In the multivariable analysis, age 70 years or older was the most strong factor associated with COPD (adjusted odds ratio [aOR], 17.86; 95% confidence interval [CI], 14.16-22.52; compared with age 40-49), followed by asthma (aOR, 3.39; 95% CI, 2.44-4.71), male sex (aOR, 2.64; 95% CI, 2.18-3.19), and current smokers (aOR, 2.60; 95% CI, 2.08-3.25). Additionally, ex-smokers, low income, decreased forced expiratory volume in 1 second %pred, and a history of pulmonary tuberculosis were associated with COPD. On the other hand, body mass index (BMI) ≥ 25 kg/m² (aOR, 0.62; 95% CI, 0.54-0.71; compared with BMI 18.5-24.9 kg/m²) had an inverse association with COPD.

CONCLUSION

Recent trends in the prevalence of COPD in South Korea are relatively stable. Approximately one-third of participants aged 70 years and older had COPD. Aging was the most important factor associated with COPD.

A Retrospective Claims Database Study to Clarify Disease Burden of Severe Asthma Patients with Type 2 High or Low Inflammation

Purpose

The disease burden of severe asthma patients stratified by type 2 (T2) biomarkers is not well studied in large patient samples, especially for T2-low severe asthma patients. Using a Japanese medical record database, we investigated disease and economic burdens in T2-high and T2-low severe asthma patients.

Patients and Methods

Data of severe asthma patients (receiving high-dose inhaled corticosteroids and additional asthma-related controller medications or oral corticosteroids [OCS] prescription [≥183 days] during the 1-year baseline period) were analyzed in the Real World Data database, comprising electronic medical records from Japanese medical institutions. Severe asthma patients were stratified into a T2-high population with higher eosinophils (≥150 cells/μL) and/or higher total immunoglobulin E (IgE, ≥75 IU/mL) or a T2-low population with lower eosinophils (<150 cells/μL) and lower total IgE (<75 IU/mL). The incidence of asthma exacerbation events and drug costs were analyzed for each population. Different T2 thresholds were explored, including eosinophil count 300 cells/μL and/or IgE 150 IU/mL.

Results

Of the 732 severe asthma patients, 599 (81.8%) patients had T2-high type, and 133 (18.2%) had T2-low type. Proportions of the T2-high patients (30.6%) with asthma exacerbations, defined as a composite outcome, including OCS burst, injectable steroid use, and hospitalization, were similar to those of T2-low type (34.6%). The annual drug cost was similar between T2-high (175,487 JPY) and T2-low (165,322 JPY) populations.

Conclusion

In this large-scale study, both T2-high and T2-low severe asthma patients in Japan were shown to have a high disease burden and high economic burden, suggesting an unmet treatment need.