Racial and sex differences in chronic obstructive pulmonary disease susceptibility, diagnosis, and treatment

Influence of ethnicity on adherence to nonsurgical interventions for COPD: a scoping review

Objective

Poor therapeutic adherence and the contributing factors have been extensively researched in several chronic diseases, including COPD. However, the influence of ethnicity on adherence to nonsurgical treatment interventions for COPD (e.g. smoking cessation and pulmonary rehabilitation) is not well understood. This scoping review was performed to better understand variations in adherence among people from minority ethnic communities diagnosed with COPD.

Method

This scoping review was designed based on the refined frameworks of Arksey and O'Malley, developed by JBI (Joanna Briggs Institute). Systematic searches were performed across three databases: CINHAL (EBSCO), MEDLINE (Ovid) and Embase (Ovid).

Results

Out of 3654 identified records, 37 studies were deemed eligible for inclusion; these were conducted in various countries and involved populations of diverse ethnic groups diagnosed with COPD. The included studies considered provision and/or adherence to medication (n=8, 21.6%), smoking cessation (n=11, 29.7%), influenza vaccinations (n=7, 18.9%), pulmonary rehabilitation (n=11, 29.7%) and oxygen therapy (n=2, 5.4%). Outcomes varied widely between studies within a single intervention (e.g. initiation, adherence and completion of pulmonary rehabilitation programme). However, most of the included studies suggested the presence of inequalities linked to ethnicity across interventions.

Conclusion

This review indicated the presence of poor adherence to nonsurgical interventions among people from minority ethnic backgrounds living with COPD. However, due to the heterogeneity in population groups considered and compared within the individual studies, it is challenging to identify and understand the key inequalities influencing adherence to nonsurgical interventions. Further research is needed to better explore this.

Sex- and Race-Based Differences in the Treatment of Interstitial Lung Diseases in North America and Australasia

BACKGROUND

Biological sex, gender, and race are important considerations in patients with interstitial lung diseases (ILDs).

RESEARCH QUESTION

Does a patient's sex assigned at birth, and race, influence ILD treatment initiation?

STUDY DESIGN AND METHODS

Patients with ILD from three longitudinal prospective registries were compared in this observational study. ILD-related medications included antifibrotics and immunomodulating medications. Race was dichotomized as "White" vs "non-White." Time to treatment initiation was determined from the date of the initial ILD registry visit to the date of first medication initiation. Proportions of treated patients were compared between groups by χ2 test. Cox proportional analysis was used to determine how sex and race were associated with time to treatment initiation stratified by ILD diagnosis.

RESULTS

A total of 4,572 patients were included across all cohorts. The proportion of men who received treatment was higher than for women in the Canadian cohort (47% vs 40%; P < .001), and the proportion of White patients who received treatment was also higher compared with non-White patients (46% vs 36%; P < .001). In contrast, the proportion of treated men in the Chicago cohort was lower compared with women (56% vs 64%; P = .005), and that of White patients was lower compared with non-White patients (56% vs 69%; P < .001). No sex- or race-based differences in proportions of patients treated were found in the Australasian cohort. White race was significantly associated with earlier treatment initiation compared with non-White race across diagnoses in the Canadian cohort, whereas the opposite association was found in the Australasian cohort.

INTERPRETATION

Sex- and race-based differences exist in the initiation of ILD treatment, with variability across different cohorts in different countries. Reasons for these differences need to be further explored in future studies.

Environmental effects on acute exacerbations of respiratory diseases: A real-world big data study

BACKGROUND

The effects of weather periods, race/ethnicity, and sex on environmental triggers for respiratory exacerbations are not well understood. This study linked the OneFlorida network (~15 million patients) with an external exposome database to analyze environmental triggers for asthma, bronchitis, and COPD exacerbations while accounting for seasonality, sex, and race/ethnicity.

METHODS

This is a case-crossover study of OneFlorida database from 2012 to 2017 examining associations of asthma, bronchitis, and COPD exacerbations with exposures to heat index, PM 2.5 and O 3. We spatiotemporally linked exposures using patients' residential addresses to generate average exposures during hazard and control periods, with each case serving as its own control. We considered age, sex, race/ethnicity, and neighborhood deprivation index as potential effect modifiers in conditional logistic regression models.

RESULTS

A total of 1,148,506 exacerbations among 533,446 patients were included. Across all three conditions, hotter heat indices conferred increasing exacerbation odds, except during November to March, where the opposite was seen. There were significant differences when stratified by race/ethnicity (e.g., for asthma in April, May, and October, heat index quartile 4, odds were 1.49 (95% confidence interval (CI) 1.42-1.57) for Non-Hispanic Blacks and 2.04 (95% CI 1.92-2.17) for Hispanics compared to 1.27 (95% CI 1.19-1.36) for Non-Hispanic Whites). Pediatric patients' odds of asthma and bronchitis exacerbations were significantly lower than adults in certain circumstances (e.g., for asthma during June - September, pediatric odds 0.71 (95% CI 0.68-0.74) and adult odds 0.82 (95% CI 0.79-0.85) for the highest quartile of PM 2.5).

CONCLUSION

This study of acute exacerbations of asthma, bronchitis, and COPD found exacerbation risk after exposure to heat index, PM 2.5 and O 3 varies by weather period, age, and race/ethnicity. Future work can build upon these results to alert vulnerable populations to exacerbation triggers.

Protocol for a feasibility randomized trial of self-management support for people with chronic obstructive pulmonary disease using lay health coaches

Challenges with self-management are a major contributor to poor outcomes among adults with chronic obstructive pulmonary disease (COPD). The causes of poor self-management in COPD are manifold, and they arise from physical, cognitive, socioeconomic, environmental and societal sources. To address this complexity, we developed the Supporting self-Management Behaviors in Adults with COPD (SaMBA-COPD) model, which uses lay health coaches to identify a patient's barriers to effective COPD self-management and provide tailored support to help them overcome those barriers, reduce their symptoms and need for urgent care and improve their quality of life. The 6-month intervention includes referral of patients to a pharmacist for prescription of antibiotic and oral steroid "rescue packs" and support for a structured home exercise routine. All interactions of coaches and patients will take place by telephone or video call. We will test the feasibility and preliminary efficacy of SaMBA-COPD in a trial of 58 patients randomized 1:1 to the intervention or a COPD education control. Outcomes will be assessed at 6 and 9 months. Data from the trial will be used to inform the design of a fully powered, multi-site randomized trial of the intervention.

Fibrinogen is a promising biomarker for chronic obstructive pulmonary disease: evidence from a meta-analysis

Backgrounds: Some studies have reported association of circulating fibrinogen with the risk of chronic obstructive pulmonary disease (COPD), and the results are conflicting. To yield more information, we aimed to test the hypothesis that circulating fibrinogen is a promising biomarker for COPD by a meta-analysis.

Methods: Data extraction and quality assessment were independently completed by two authors. Effect-size estimates are expressed as weighted mean difference (WMD) with 95% confidence interval (95% CI).

Results: Forty-five articles involving 5586/18604 COPD patients/controls were incorporated. Overall analyses revealed significantly higher concentrations of circulating fibrinogen in COPD patients than in controls (WMD: 84.67 mg/dl; 95% CI: 64.24–105.10). Subgroup analyses by COPD course showed that the degree of increased circulating fibrinogen in patients with acute exacerbations of COPD (AECOPD) relative to controls (WMD: 182.59 mg/dl; 95% CI: 115.93–249.25) tripled when compared in patients with stable COPD (WMD: 56.12 mg/dl; 95% CI: 34.56–77.67). By COPD severity, there was a graded increase in fibrinogen with the increased severity of COPD relative to controls (Global Initiative for Obstructive Lung Disease (GOLD) I, II, III, and IV: WMD: 13.91, 29.19, 56.81, and 197.42 mg/dl; 95% CI: 7.70–20.11, 17.43–40.94, 39.20–74.41, and −7.88 to 402.73, respectively). There was a low probability of publication bias.

Conclusion: Our findings indicate a graded, concentration-dependent, significant relation between higher circulating fibrinogen and more severity of COPD.

Prediction of COPD risk accounting for time-varying smoking exposures

RATIONALE

Chronic Obstructive Pulmonary Disease (COPD) is the fourth leading cause of death in the United States. Studies have primarily assessed the relationship between smoking on COPD risk focusing on summary measures, like smoking status.

OBJECTIVE

Develop a COPD risk prediction model incorporating individual time-varying smoking exposures.

METHODS

The Nurses' Health Study (N = 86,711) and the Health Professionals Follow-up Study (N = 39,817) data was used to develop a COPD risk prediction model. Data was randomly split in 50-50 samples for model building and validation. Cox regression with time-varying covariates was used to assess the association between smoking duration, intensity and year-since-quit and self-reported COPD diagnosis incidence. We evaluated the model calibration as well as discriminatory accuracy via the Area Under the receiver operating characteristic Curve (AUC). We computed 6-year risk of COPD incidence given various individual smoking scenarios.

RESULTS

Smoking duration, year-since-quit (if former smokers), sex, and interaction of sex and smoking duration are significantly associated with the incidence of diagnosed COPD. The model that incorporated time-varying smoking variables yielded higher AUCs compared to models using only pack-years. The AUCs for the model were 0.80 (95% CI: 0.74-0.86) and 0.73 (95% CI: 0.70-0.77) for males and females, respectively.

CONCLUSIONS

Utilizing detailed smoking pattern information, the model predicts COPD risk with better accuracy than models based on only smoking summary measures. It might serve as a tool for early detection programs by identifying individuals at high-risk for COPD.

Association Between Rural Residence and In-Hospital and 30-Day Mortality Among Veterans Hospitalized with COPD Exacerbations

Background

We explored the relationship between rural residency and in-hospital mortality in patients hospitalized with COPD exacerbations.

Methods

We retrospectively analyzed COPD hospitalizations from 2011 to 2017 at 124 acute care Veterans Health Administration (VHA) hospitals in the US. Patient residence was classified using Rural Urban Commuting Area codes as urban, rural, or isolated rural. We stratified patient hospitalizations into quartiles by travel time from patient residence to the nearest VHA primary care provider clinic and hospital. Multivariate analyses utilized generalized estimating equations with a logit link accounting for repeated hospitalizations among patients and adjusting for patient- and hospital-level characteristics.

Results

Of 64,914 COPD hospitalizations analyzed, 43,549 (67.1%) were for urban, 18,673 (28.8%) for rural, and 2,692 (4.1%) for isolated rural veterans. In-hospital mortality was 4.9% in urban, 5.5% in rural, and 5.2% in isolated rural veterans (P=0.008). Thirty-day mortality was 8.3% in urban, 9.9% in rural, and 9.2% in isolated rural veterans (P<0.001). Travel time to a primary care provider and VHA hospital was not associated with in-hospital mortality among isolated rural and rural veterans. In the multivariable analysis, compared to urban veterans, isolated rural patients did not have increased mortality. Rural residence was not associated with in-hospital (OR=0.87; 95% CI=0.67-1.12, P=0.28) but was associated with increased 30-day mortality (OR=1.13; 95% CI=1.04-1.22, P=0.002). Transfer from another acute care hospital (OR=14.97; 95% CI=9.80-17.16, P<0.001) or an unknown/other facility (OR=33.05; 95% CI=22.66-48.21, P<0.001) were the strongest predictors of increased in-hospital mortality compared to patients coming from the outpatient sector. Transfer from another acute care facility was also a risk factor for 30-day mortality.

Conclusion

Potential gaps in post-discharge care of rural veterans may be responsible for the rural-urban disparities. Further research should investigate the exact mechanism that inter-hospital transfers affect mortality.

A Between Ethnicities Comparison of Chronic Obstructive Pulmonary Disease Genetic Risk

Heterogeneity of lung function levels and risk for developing chronic obstructive pulmonary disease (COPD) among people exposed to the same environmental risk factors, such as cigarette smoking, suggest an important role of genetic factors in COPD susceptibility. To investigate the possible role of different genetic factors in COPD susceptibility across ethnicities. We used a population-stratified analysis for: (i) identifying ethnic-specific genetic susceptibility loci, (ii) developing ethnic-specific polygenic risk prediction models using those SNPs, and (iii) validating the models with an independent dataset. We elucidated substantial differences in SNP heritability and susceptibility loci for the disease across ethnicities. Furthermore, the application of three ethnic-specific prediction models to an independent dataset showed that the best performance is achieved when the prediction model is applied to a dataset with the matched ethnic sample. Our study validates the necessity of considering ethnic differences in COPD risk; understanding these differences might help in preventing COPD and developing therapeutic strategies.

Risk factors associated with physical and mental distress in people who report a COPD diagnosis: latent class analysis of 2016 behavioral risk factor surveillance system data

Introduction

Challenges associated with COPD increase patients’ risk of physical immobility and emotional distress, perpetuating a cycle of symptomatic living that hinders patients’ self-management and adherence to a treatment regimen. There is limited evidence available on how discrete behavioral and health risk factors contribute to the physical and mental distress experienced by people living with COPD.

Purpose

This secondary data analysis of 2016 Behavioral Risk Factor Surveillance System (BRFSS) sought to identify subgroups of people with COPD who were at the highest risk for physical and mental distress.

Methods

We selected 16 relevant risk indicators in four health-related domains – 1) health risk behaviors, 2) lack of preventive vaccinations, 3) limited health care access, and 4) comorbidities – as predictors of physical and mental health-related quality of life (HRQoL) in the COPD population. Latent class modeling (LCM) was applied to understand how various health-related indicators in these four health domains influenced reports of physical and/or mental distress.

Results

The majority of BRFSS respondents who reported a COPD diagnosis experienced physical (53.76%) and/or mental (58.23%) distress in the past 14 days. Frequent physical and mental distress were more common in females with COPD in the 45–64 years age group, who were also identified as white and in the lower socioeconomic group. Respondents with intermediate- to high-risk behaviors, intermediate to multiple comorbidities, limited access to health care, and intermediate to low use of preventive vaccinations were more likely to report frequent physical distress compared to the low-risk respondents. Similarly, respondents with high-risk behaviors, intermediate to multiple comorbidities, and low use of preventive vaccinations were more likely to report frequent mental distress than the low-risk group.

Discussion

This analysis of updated 2016 BRFSS data identified high-risk Americans with COPD who could benefit from disease management and secondary/tertiary health promotion interventions that may improve HRQoL. Future research should address noted disparities in risk factors, particularly among low socioeconomic populations living with COPD.

The 10,000 Immunomes Project: Building a Resource for Human Immunology

There is increasing appreciation that the immune system plays critical roles not only in the traditional domains of infection and inflammation but also in many areas of biology, including tumorigenesis, metabolism, and even neurobiology. However, one of the major barriers for understanding human immunological mechanisms is that immune assays have not been reproducibly characterized for a sufficiently large and diverse healthy human cohort. Here, we present the 10,000 Immunomes Project (10KIP), a framework for growing a diverse human immunology reference, from ImmPort, a publicly available resource of subject-level immunology data. Although some measurement types are sparse in the presently deposited ImmPort database, the extant data allow for a diversity of robust comparisons. Using 10KIP, we describe variations in serum cytokines and leukocytes by age, race, and sex; define a baseline cell-cytokine network; and describe immunologic changes in pregnancy. All data in the resource are available for visualization and download at http://10kimmunomes.org/.

Racial Differences in Mortality from Severe Acute Respiratory Failure in the United States, 2008-2012

RATIONALE

Racial disparities in health and healthcare in the United States are well documented and are increasingly recognized in acute critical illnesses such as sepsis and acute respiratory failure.

OBJECTIVES

Using a large, representative, U.S. nationwide database, we examined the hypothesis that black and Hispanic patients with severe acute respiratory failure have higher mortality rates when compared with non-Hispanic whites.

METHODS

This retrospective analysis used discharge data from the Agency for Healthcare Research and Quality, Nationwide Inpatient Sample, Healthcare Cost and Utilization Project, for the years 2008-2012. We identified hospitalizations with acute respiratory failure using a combination of International Classification of Diseases, Ninth Revision, Clinical Modification, codes. A logistic regression model was fitted to compare in-hospital mortality rates by race.

MEASUREMENTS AND MAIN RESULTS

After adjusting for sex, age, race, disease severity, type of hospital, and median household income for patient ZIP code, blacks had a greater odds ratio of in-hospital death when compared with non-Hispanic whites (odds ratio [OR], 1.13; 95% confidence interval [CI], 1.11-1.14; P < 0.001), and Hispanics also had a greater odds ratio of in-hospital death when compared with non-Hispanic whites (OR, 1.17; 95% CI, 1.15-1.19; P < 0.001), and so did Asian and Pacific Islanders (OR, 1.15; 95% CI, 1.12-1.18; P < 0.001) and Native Americans (OR, 1.08; 95% CI, 1.00-1.15; P < 0.001) when compared with non-Hispanic whites (OR, 1.0).

CONCLUSIONS

Blacks, Hispanics, and other racial minorities in the United States were observed to exhibit significantly higher in-hospital sepsis-related respiratory failure associated mortality when compared with non-Hispanic whites.

Sex and racial/ethnic differences in the reason for 30-day readmission after COPD hospitalization

BACKGROUND

Reduction of 30-day readmissions in patients hospitalized for chronic obstructive pulmonary disease (COPD) is a national objective. However, there is a dearth of research on sex and racial/ethnic differences in the reason for 30-day readmission.

METHODS

We conducted a retrospective cohort study using 2006-2012 data from the State Inpatient Database of eight geographically-diverse US states (Arkansas, California, Florida, Iowa, Nebraska, New York, Utah, and Washington). After identifying all hospitalizations for COPD made by patients aged ≥40 years, we investigated the primary diagnostic code for all-cause readmissions within 30 days after the original COPD hospitalization, among the overall group and by sex and race/ethnicity strata.

RESULTS

Between 2006 and 2012, there was a total of 845,465 COPD hospitalizations at risk for 30-day readmissions in the eight states. COPD was the leading diagnostic for 30-day readmission after COPD hospitalization, both overall (28%) and across all sex and race/ethnicity strata. The proportion of respiratory diseases (COPD, pneumonia, respiratory failure, and asthma) as the readmission diagnosis was higher in non-Hispanic black (55%), compared to non-Hispanic white (52%) and Hispanics (51%) (p < 0.001). The proportion of asthma as the readmission diagnosis differed significantly by sex (6% in men and 9% in women; p < 0.001). Similarly, the proportion of asthma also differed significantly by race/ethnicity (5% in non-Hispanic white, 16% in non-Hispanic black, 15% in Hispanics, 13% in others; p < 0.001).

CONCLUSIONS

In this analysis of all-payer population-based data, we found sex and racial/ethnic differences in the reason for 30-day readmission in patients hospitalized for COPD.

Sociodemographic Patterns of Chronic Disease: How the Mid-South Region Compares to the Rest of the Country

INTRODUCTION

States in the Mid-South region are among the least healthy in the nation. This descriptive study examines sociodemographic differences in the distribution of chronic diseases and health-related behaviors in the Mid-South versus the rest of the U.S., identifying subgroups at increased risk of chronic disease.

METHODS

Data were obtained from the 2013 Behavioral Risk Factor Surveillance System; analyses were completed in January 2016. Twelve chronic health conditions were assessed: obesity, diabetes, high blood pressure, coronary heart disease, myocardial infarction, stroke, chronic kidney disease, cancer, arthritis, asthma, chronic obstructive pulmonary disease, and depression. Evaluated health-related behaviors included smoking, physical activity, and fruit and vegetable consumption. Age-standardized percentages were reported using complex survey design parameters to enhance generalizability.

RESULTS

The Mid-South population had increased rates of chronic disease and worse health-related behaviors than the rest of the U.S.

POPULATION

Mid-South blacks had the highest percentages of obesity, diabetes, high blood pressure, and stroke of all subgroups, along with lower physical activity and fruit and vegetable consumption. In both races and regions, individuals with lower income and education had higher rates of chronic disease and unhealthy behaviors than those with higher income and education. However, black men in both regions had higher obesity and cancer rates in the higher education category. In general, education-level disparities were more pronounced in health-related behaviors, whereas income-level disparities were more pronounced in chronic health conditions.

CONCLUSIONS

Future studies should test tailored interventions to address the specific needs of population subgroups in order to improve their health.

Total particulate matter concentration skews cigarette smoke's gene expression profile

Exposure of small animals to cigarette smoke is widely used as a model to study the pathogenesis of chronic obstructive pulmonary disease. However, protocols and exposure systems utilised vary substantially and it is unclear how these different systems compare. We analysed the gene expression profile of six publically available murine datasets from different cigarette smoke-exposure systems and related the gene signatures to three clinical cohorts. 234 genes significantly regulated by cigarette smoke in at least one model were used to construct a 55-gene network containing 17 clusters. Increasing numbers of differentially regulated clusters were associated with higher total particulate matter concentrations in the different datasets. Low total particulate matter-induced genes mainly related to xenobiotic/detoxification responses, while higher total particulate matter activated immune/inflammatory processes in addition to xenobiotic/detoxification responses. To translate these observations to the clinic, we analysed the regulation of the revealed network in three human cohorts. Similar to mice, we observed marked differences in the number of regulated clusters between the cohorts. These differences were not determined by pack-year. Although none of the experimental models exhibited a complete alignment with any of the human cohorts, some exposure systems showed higher resemblance. Thus, depending on the cohort, clinically observed changes in gene expression may be mirrored more closely by specific cigarette smoke exposure systems. This study emphasises the need for careful validation of animal models.

A systematic review and meta-analysis-does chronic obstructive pulmonary disease predispose to bronchopleural fistula formation in patients undergoing lung cancer surgery?

BACKGROUND

we conducted this systematic meta-analysis to determine the association between chronic obstructive pulmonary disease (COPD) and risk of bronchopleural fistula (BPF) in patients undergoing lung cancer surgery.

METHODS

Literature retrieval was performed in PubMed, Embase and the Web of Science to identify the full-text articles that met our eligibility criteria. Odds ratio (OR) with 95% confidence interval (CI) served as the summarized statistics. Q-test and I(2)-statistic were used to evaluate the level of heterogeneity. Sensitivity analysis was performed to further examine the stability of pooled OR. Publication bias was detected by both Begg's test and Egger's test.

RESULTS

Eight retrospective observational studies were included into this meta-analysis. The overall summarized OR was 2.03 (95% CI: 1.44-2.86; P<0.001), revealing that COPD was significantly associated with the risk of BPF after lung cancer surgery. In subgroup analysis, the relationship between COPD and BPF occurrence remained statistically prominent in the subgroups stratified by statistical analysis (univariate analysis, OR: 1.91; 95% CI: 1.35-2.69; P<0.001; multivariate analysis, OR: 3.18; 95% CI: 1.95-5.19; P<0.001), operative modes (pneumonectomy, OR: 2.11; 95% CI: 1.15-3.87; P=0.016) and in non-Asian populations (OR: 2.36; 95% CI: 1.18-4.73; P=0.016). No significant impact of COPD on BPF risk was observed in Asian patients (OR: 1.48; 95% CI: 0.85-2.57; P=0.16). No significant heterogeneity or publication bias was discovered across the included studies.

CONCLUSIONS

Our meta-analysis indicates that COPD can significantly predispose to BPF formation in patients undergoing lung cancer surgery. Because some limitations still exist in this meta-analysis, our findings should be further verified and modified in the future.

Sex Difference in Chronic Obstructive Lung Disease. Does it Matter? A Concise Review

Chronic obstructive lung disease (COPD) primarily affects men; however, its epidemiology has been changing because more women have become smokers. Recently, investigators found that although women and men were exposed to the same amount of smoke fume, women tended to have more severe disease and higher mortality rate. They also complain of more dyspnoea and may experience more severe exacerbations than men. This led to the question of whether sex has an impact on COPD course and whether women have a higher susceptibility to smoke fumes than men. That may be explained by multiple complex factors highlighting the relationship between sex, epidemiology, method of diagnostics and the clinical course of the disease. In this review, sex differences in epidemiology, clinical presentation, exacerbation, co-morbidities and treatment are covered.

Vulnerability to Renal, Heat and Respiratory Hospitalizations During Extreme Heat Among U.S. Elderly

BACKGROUND

Extreme heat (EH) is a growing concern with climate change, and protecting human health requires knowledge of vulnerability factors. We evaluated whether associations between EH (maximum temperature > 97th percentile) and hospitalization for renal, heat and respiratory diseases among people ≥ 65 years differed by individual and area-level characteristics.

METHODS

We used Medicare billing records, airport weather data, U.S. Census data and satellite land cover imagery in 109 US cities, May-September, 1992-2006, in a time-stratified case-crossover design. Interaction terms between EH and individual (> 78 years, black race, sex) and home ZIP-code (percentages of non-green space, high school education, housing built before 1940) characteristics were incorporated in a single model. Next, we pooled city-specific effect estimates or regressed them on quartiles of air conditioning prevalence (ACP) in a multivariate random effects meta-analysis.

RESULTS

EH and combined renal/heat/respiratory hospitalization associations were stronger among blacks, the very old, in ZIP codes with lower educational attainment or older housing and in cities with lower ACP. For example, for EH versus non-heat days, we found a 15% (95% CI 11%-19%) increase in renal/heat/respiratory hospitalizations among individuals in ZIP codes with higher percent of older homes in contrast to a 9% (95% CI 6%-12%) increase in hospitalizations in ZIP codes with lower percent older homes.

CONCLUSION

Vulnerability to EH-associated hospitalization may be influenced by age, educational attainment, housing age and ACP.

Does COPD risk vary by ethnicity? A retrospective cross-sectional study

BACKGROUND

Lower risk of COPD has been reported in black and Asian people, raising questions of poorer recognition or reduced susceptibility. We assessed prevalence and severity of COPD in ethnic groups, controlling for smoking.

METHOD

A retrospective cross-sectional study using routinely collected primary care data in London. COPD prevalence, severity (% predicted forced expiratory volume in 1 second [FEV1]), smoking status, and treatment were compared between ethnic groups, adjusting for age, sex, smoking, deprivation, and practice clustering.

RESULTS

Among 358,614 patients in 47 general practices, 47.6% were white, 20% black, and 5% Asian. Prevalence of COPD was 1.01% overall, 1.55% in whites, 0.58% in blacks, and 0.78% in Asians. COPD was less likely in blacks (adjusted odds ratio [OR], 0.44; 95% confidence interval [CI] 0.39-0.51) and Asians (0.82; CI, 0.68-0.98) than whites. Black COPD patients were less likely to be current smokers (OR, 0.56; CI, 0.44-0.71) and more likely to be never-smokers (OR, 4.9; CI, 3.4-7.1). Treatment of patients with similar disease severity was similar irrespective of ethnic origin, except that long-acting muscarinic antagonists were prescribed less in black COPD patients (OR, 0.53; CI, 0.42-0.68). Black ethnicity was a predictor of poorer lung function (% predicted FEV1: B coefficient, -7.6; P<0.0001), an effect not seen when ethnic-specific predicted FEV1 values were used.

CONCLUSION

Black people in London were half as likely as whites to have COPD after adjusting for lower smoking rates in blacks. It seems likely that the differences observed were due either to ethnic differences in the way cigarettes were smoked or to ethnic differences in susceptibility to COPD.

Chronic obstructive pulmonary disease (COPD) assessment test scores corresponding to modified Medical Research Council grades among COPD patients

BACKGROUND/AIMS

In assigning patients with chronic obstructive pulmonary disease (COPD) to subgroups according to the updated guidelines of the Global Initiative for Chronic Obstructive Lung Disease, discrepancies have been noted between the COPD assessment test (CAT) criteria and modified Medical Research Council (mMRC) criteria. We investigated the determinants of symptom and risk groups and sought to identify a better CAT criterion.

METHODS

This retrospective study included COPD patients seen between June 20, 2012, and December 5, 2012. The CAT score that can accurately predict an mMRC grade ≥ 2 versus < 2 was evaluated by comparing the area under the receiver operating curve (AUROC) and by classification and regression tree (CART) analysis.

RESULTS

Among 428 COPD patients, the percentages of patients classified into subgroups A, B, C, and D were 24.5%, 47.2%, 4.2%, and 24.1% based on CAT criteria and 49.3%, 22.4%, 8.9%, and 19.4% based on mMRC criteria, respectively. More than 90% of the patients who met the mMRC criteria for the 'more symptoms group' also met the CAT criteria. AUROC and CART analyses suggested that a CAT score ≥ 15 predicted an mMRC grade ≥ 2 more accurately than the current CAT score criterion. During follow-up, patients with CAT scores of 10 to 14 did not have a different risk of exacerbation versus those with CAT scores < 10, but they did have a lower exacerbation risk compared to those with CAT scores of 15 to 19.

CONCLUSIONS

A CAT score ≥ 15 is a better indicator for the 'more symptoms group' in the management of COPD patients.

Racial Differences in Chronic Conditions and Sociodemographic Characteristics Among High-Utilizing Veterans

PURPOSE

African-Americans are disproportionally represented among high-risk, high-utilizing patients. To inform program development for this vulnerable population, the current study describes racial variation in chronic conditions and sociodemographic characteristics among high-utilizing patients in the Veterans Affairs Healthcare System (VA).

METHODS

We identified the 5 % most costly Veterans who used inpatient or outpatient care at the VA during fiscal year 2010 (N = 237,691) based on costs of inpatient and outpatient care, pharmacy services, and VA-sponsored contract care. Patient costs and characteristics were abstracted from VA outpatient and inpatient data files. Racial differences in sociodemographic characteristics (age, sex, marital support, homelessness, and health insurance status) were assessed with chi-square tests. Racial differences in 32 chronic condition diagnoses were calculated as relative risk ratios.

RESULTS

African-Americans represented 21 % of high-utilizing Veterans. African-Americans had higher rates of homelessness (26 vs. 10 %, p < 0.001) and lower rates of supplemental health insurance (44 vs. 58 %, p < 0.001). The mean number of chronic conditions was similar across race. However, there were racial differences in the prevalence of specific chronic conditions, including a higher prevalence of HIV/AIDS (95 % confidence interval (CI) 4.86, 5.50) and schizophrenia (95 % CI 1.94, 2.07) and a lower prevalence of ischemic heart disease (95 % CI 0.57, 0.59) and bipolar disorder (95 % CI 0.78, 0.85) among African-American high-utilizing Veterans.

CONCLUSION

Racial disparities among high-utilizing Veterans may differ from those found in the general population. Interventions should devote attention to social, environmental, and mental health issues in order to reduce racial disparities in this vulnerable population.

Ethics and policy issues for stem cell research and pulmonary medicine

Stem cell research and related initiatives in regenerative medicine, cell-based therapy, and tissue engineering have generated considerable scientific and public interest. Researchers are applying stem cell technologies to chest medicine in a variety of ways: using stem cells as models for drug discovery, testing stem cell-based therapies for conditions as diverse as COPD and cystic fibrosis, and producing functional lung and tracheal tissue for physiologic modeling and potential transplantation. Although significant scientific obstacles remain, it is likely that stem cell-based regenerative medicine will have a significant clinical impact in chest medicine. However, stem cell research has also generated substantial controversy, posing a variety of ethical and regulatory challenges for research and clinical practice. Some of the most prominent ethical questions related to the use of stem cell technologies in chest medicine include (1) implications for donors, (2) scientific prerequisites for clinical testing and use, (3) stem cell tourism, (4) innovation and clinical use of emerging stem cell-based interventions, (5) responsible translation of stem cell-based therapies to clinical use, and (6) appropriate and equitable access to emerging therapies. Having a sense of these issues should help to put emerging scientific advances into appropriate context and to ensure the responsible clinical translation of promising therapeutics.

Chronic Obstructive Pulmonary Disease Illness and Medication Beliefs are Associated with Medication Adherence

Almost half of patients with COPD do not adhere to their medications. Illness and medication beliefs are important determinants of adherence in other chronic diseases. Using the framework of the Common Sense Model of Self-Regulation (CSM), we determined associations between potentially modifiable beliefs and adherence to COPD medications in a cohort of English- and Spanish-speaking adults with COPD from New York and Chicago. Medication adherence was assessed using the Medication Adherence Report Scale. Illness and medication beliefs along CSM domains were evaluated using the Brief Illness Perception Questionnaire (B-IPQ) and the Beliefs about Medications Questionnaire (BMQ). Unadjusted analysis (with Cohen's d effect sizes) and multiple logistic regression were used to assess the relationship between illness and medication beliefs with adherence. The study included 188 participants (47% Black, 13% Hispanics); 109 (58%) were non-adherent. Non-adherent participants were younger (p < 0.001), more likely to be Black or Hispanic (p = 0.001), to have reported low income (p = 0.02), and had fewer years of formal education (p = 0.002). In unadjusted comparisons, non-adherent participants reported being more concerned about their COPD (p = 0.011; Cohen's d = 0.43), more emotionally affected by the disease (p = 0.001; Cohen's d = 0.54), and had greater concerns about COPD medications (p < 0.001, Cohen's d = 0.81). In adjusted analyses, concerns about COPD medications independently predicted non-adherence (odds ratio: 0.52, 95% confidence interval: 0.36-0.75). In this cohort of urban minority adults, concerns about medications were associated with non-adherence. Future work should explore interventions to influence patient adherence by addressing concerns about the safety profile and long-term effects of COPD medications.

Efficacy and safety of once-daily glycopyrronium in predominantly Chinese patients with moderate-to-severe chronic obstructive pulmonary disease: the GLOW7 study

BACKGROUND

Glycopyrronium is a once-daily (od) long-acting muscarinic antagonist for the maintenance treatment of chronic obstructive pulmonary disease (COPD). The GLOW7 study evaluated the efficacy and safety of od glycopyrronium 50 μg in predominantly Chinese patients with moderate-to-severe COPD.

METHODS

In this 26-week, multi-center, double-blind, placebo-controlled, parallel-group study, men and women ≥40 years with moderate-to-severe COPD were randomized to glycopyrronium 50 μg od or placebo (2:1). The primary objective was to confirm the significant improvement of trough forced expiratory volume in 1 second (FEV1) following 12 weeks of treatment with glycopyrronium compared with placebo. Secondary objectives included the effect of glycopyrronium on health status (St George's Respiratory Questionnaire), breathlessness (Transition Dyspnea Index), other lung function parameters, rescue medication use, and COPD exacerbations. Safety and tolerability were also evaluated.

RESULTS

Of the 460 patients randomized, 459 were included in the full analysis set (glycopyrronium, n=306; placebo, n=154; mean age 64.7 years; mean post-bronchodilator FEV1: 50.8% predicted); 425 (92.4%) completed the study. At Week 12, glycopyrronium signifcantly improved trough FEV1 with a least square means treatment difference of 141 mL (95% confidence interval 111 mL, 171 mL; P<0.001) compared with placebo. The mean treatment effect of glycopyrronium was greater than the minimum clinically important difference versus placebo in both St George's Respiratory Questionnaire total score (-4.92; P<0.001) and Transition Dyspnea Index focal score (1.0; P<0.001) at week 26. Glycopyrronium reduced the risk of exacerbations in terms of time to first moderate or severe exacerbation by 28% (P=0.153) and rate of moderate or severe COPD exacerbation by 29% (P=0.119) compared with placebo. Incidence of death was 1.3% with glycopyrronium and 0% in placebo during the treatment period. Overall incidence of adverse events (glycopyrronium 43.6%; placebo 47.4%) and serious adverse events (glycopyrronium 5.6%; placebo 9.1%) were similar.

CONCLUSION

In predominantly Chinese patients with moderate-to-severe COPD, od glycopyrronium 50 μg significantly improved lung function, dyspnea, and health status compared with placebo. The safety and tolerability profile of glycopyrronium was comparable to placebo.

Heredity of chronic bronchitis: a registry-based twin study

BACKGROUND

Smoking is a major risk factor for lung diseases and lower respiratory symptoms, but since not all smokers develop chronic bronchitis and since chronic bronchitis is also diagnosed in never-smokers, it has been suggested that some individuals are more susceptible to develop chronic bronchitis due to genetics.

OBJECTIVE

To study the relative influence of genetic and environmental factors on the variation in the susceptibility to chronic bronchitis.

METHODS

In a population-based questionnaire study of 13,649 twins, 50-71 years of age, from the Danish Twin Registry, we calculated sex-specific concordance rates and heritability of chronic bronchitis. The response rate was 75%.

RESULTS

The prevalence of chronic bronchitis was 9.3% among men and 8.5% among women. The concordance rate for chronic bronchitis was higher in monozygotic twins than in dizygotic twins among women; 0.30 vs. 0.17, but not among men; 0.15 vs. 0.18. The heritability of chronic bronchitis adjusted for smoking and age was 55% (36-71%) in women, whereas the susceptibility to chronic bronchitis in men for 25% (8-41%) was ascribable to familial environment but not to genetic factors.

CONCLUSIONS

Chronic bronchitis shows a moderate familial aggregation, particularly in women. Increased susceptibility to respiratory disease among female smokers relative to male smokers may have a genetic origin.

Tobacco smoke exposure in pulmonary arterial and thromboembolic pulmonary hypertension

BACKGROUND

Animal studies and data from a single-center study suggest that tobacco smoke exposure may be a risk factor for precapillary pulmonary hypertension (PH).

OBJECTIVE

We aimed to survey tobacco smoke exposure in a large PH collective and to compare it with epidemiological data from healthy subjects.

METHODS

This is an international, multicenter, case-control study including patients with pulmonary arterial and chronic thromboembolic PH. All patients were asked specific questions about tobacco smoke exposure. Healthy controls were retrieved from the Swiss Health Survey (n = 18,747).

RESULTS

Overall (n = 472), 49% of PH patients were smokers and there was a clear sex difference (women 37%, men 71%). Significantly more PH men were smokers compared with healthy controls, whereas less PH women were ever active smokers. However, 50% of the non-smoking PH women were exposed to secondhand smoke, leading to a significantly higher number of tobacco smoke-exposed individuals compared to healthy controls. PH smokers were significantly younger compared to those not exposed.

CONCLUSION

Active and environmental tobacco smoke exposure is common in PH. The higher prevalence of male PH smokers, the higher exposure to environmental tobacco smoke in PH women compared to healthy controls and the lower age at PH diagnosis in smokers may indicate a pathogenic role of tobacco smoke exposure in PH.

Study Design and Outcomes of Korean Obstructive Lung Disease (KOLD) Cohort Study

Background

The Korean Obstructive Lung Disease (KOLD) Cohort Study is a prospective longitudinal study of patients with chronic obstructive pulmonary disease (COPD), asthma, or other unclassified obstructive lung diseases. It was designed to develop new classification models and biomarkers that predict clinically relevant outcomes for patients with obstructive lung diseases.

Methods

Patients over 18 years old who have chronic respiratory symptoms and airflow limitations or bronchial hyper-responsiveness were enrolled at 17 centers in South Korea. After a baseline visit, the subjects were followed up every 3 months for various assessments.

Results

From June 2005 to October 2013, a total of 477 subjects (433 [91%] males; 381 [80%] diagnosed with COPD) were enrolled. Analyses of the KOLD Cohort Study identified distinct phenotypes in patients with COPD, and predictors of therapeutic responses and exacerbations as well as the factors related to pulmonary hypertension in COPD. In addition, several genotypes were associated with radiological phenotypes and therapeutic responses among Korean COPD patients.

Conclusion

The KOLD Cohort Study is one of the leading long-term prospective longitudinal studies investigating heterogeneity of the COPD and is expected to provide new insights for pathogenesis and the long-term progression of COPD.

Relationships among smoking habits, airflow limitations, and metabolic abnormalities in school workers

Background

Chronic obstructive pulmonary disease is caused mainly by habitual smoking and is common among elderly individuals. It involves not only airflow limitation but also metabolic disorders, leading to increased cardiovascular morbidity and mortality.

Objective

We evaluated relationships among smoking habits, airflow limitation, and metabolic abnormalities.

Methods

Between 2001 and 2008, 15,324 school workers (9700 males, 5624 females; age: ≥30 years) underwent medical checkups, including blood tests and spirometry. They also responded to a questionnaire on smoking habits and medical history.

Results

Airflow limitation was more prevalent in current smokers than in ex-smokers and never-smokers in men and women. The frequency of hypertriglyceridemia was higher in current smokers in all age groups, and those of low high-density-lipoprotein cholesterolemia and diabetes mellitus were higher in current smokers in age groups ≥ 40 s in men, but not in women. There were significant differences in the frequencies of metabolic abnormalities between subjects with airflow limitations and those without in women, but not in men. Smoking index was an independent factor associated with increased frequencies of hypertriglyceridemia (OR 1.015; 95% CI: 1.012–1.018; p<0.0001) and low high-density-lipoprotein cholesterolemia (1.013; 1.010–1.016; p<0.0001) in men. Length of smoking cessation was an independent factor associated with a decreased frequency of hypertriglyceridemia (0.984; 0.975–0.994; p = 0.007).

Conclusions

Habitual smoking causes high incidences of airflow limitation and metabolic abnormalities. Women, but not men, with airflow limitation had higher frequencies of metabolic abnormalities.

Chronic obstructive pulmonary disease and cardiovascular disease

Chronic obstructive pulmonary disease (COPD) is an inflammatory disease of the lung associated with progressive airflow limitation and punctuated by episodes of acute exacerbation. There is growing recognition that the inflammatory state associated with COPD is not confined to the lungs but also involves the systemic circulation and can impact nonpulmonary organs. Epidemiologic and mechanistic studies indicate that COPD is associated with a high frequency of coronary artery disease, congestive heart failure and cardiac arrhythmias, independent of shared risk factors. Possible pathways include complex interrelationships between chronic low-grade systemic inflammation and oxidative stress as well as shared risk factors such as age, cigarette smoking, and environmental pollutants. In this review, we provide an overview of the epidemiologic data linking COPD with cardiovascular disease, comment on the interrelationships among COPD, inflammation, and cardiovascular disease, and highlight diagnostic and therapeutic challenges.

Racial differences in CT phenotypes in COPD

BACKGROUND

Whether African Americans (AA) are more susceptible to COPD than non-Hispanic Whites (NHW) and whether racial differences in disease phenotype exist is controversial. The objective is to determine racial differences in the extent of emphysema and airway remodeling in COPD.

METHODS

First, 2,500 subjects enrolled in the COPDGene study were used to evaluate racial differences in quantitative CT (QCT) parameters of% emphysema, air trapping and airway wall thickness. Independent variables studied included race, age, gender, education, BMI, pack-years, smoking status, age at smoking initiation, asthma, previous work in dusty job, CT scanner and center of recruitment.

RESULTS

Of the 1,063 subjects with GOLD Stage II-IV COPD, 200 self-reported as AA. AAs had a lower mean% emphysema (13.1% vs. 16.1%, p = 0.005) than NHW and proportionately less emphysema in the lower lung zones. After adjustment for covariates, there was no statistical difference by race in air trapping or airway wall thickness. Measured QCT parameters were more predictive of poor functional status in NHWs compared to AAs.

CONCLUSIONS

AAs have less emphysema than NHWs but the same degree of airway disease. Additional factors not easily assessed by current QCT techniques may account for the poor functional status in AAs.

We can do better than last place: improving the health of us women

Life expectancy for US women lags behind that for women in other countries. Factors contributing to inequitable health for women are complex and include policy, community, healthcare access, and the interaction between the patient and her healthcare provider working within the healthcare system. We propose a societal pyramid of health accounting for the effects of these different factors and their impact on prevention, screening, diagnosis, and management of disease using the examples of smoking and obesity, two of the most important yet modifiable risk factors for chronic disease and death among US women.

Association between antibiotic treatment and outcomes in patients hospitalized with acute exacerbation of COPD treated with systemic steroids

BACKGROUND

Antibiotics are widely used in acute exacerbations of COPD (AE-COPD), but their additional benefit to a therapeutic regimen that already includes steroids is uncertain. We evaluated the association between antibiotic therapy and outcomes among a large cohort of patients treated with steroids who were hospitalized with AE-COPD and compared the effectiveness of three commonly used antibiotic regimens.

METHODS

We conducted a retrospective cohort study of patients aged 40 years hospitalized for AE-COPD from January 1, 2006, through December 1, 2007, at 410 acute care hospitals throughout the United States.

RESULTS

Of the 53,900 patients who met the inclusion criteria, 85% were treated with antibiotics in the first 2 hospital days; 50% were treated with a quinolone, 22% with macrolides plus cephalosporin, and 9% with macrolide monotherapy. Compared with patients not treated with antibiotics, those who received antibiotics had lower mortality (1% vs 1.8%, P < .0001). In multivariable analysis, receipt of antibiotics was associated with a 40% reduction in the risk of in-hospital mortality (RR, 0.60; 95% CI, 0.50-0.73) and a 13% reduction in the risk of 30-day readmission for COPD (RR, 0.87; 95% CI, 0.79-0.96). The risk of late ventilation and readmission for Clostridium difficile colitis was not significantly different between the two groups. We found little difference in the outcomes associated with three common antibiotic treatment choices.

CONCLUSIONS

Our results suggest that the addition of antibiotics to a regimen that includes steroids may have a beneficial effect on short-term outcomes for patients hospitalized with AE-COPD.

The effect of race and chronic obstructive pulmonary disease on long-term survival after coronary artery bypass grafting

Background: Chronic obstructive pulmonary disease (COPD) is a known predictor of decreased long-term survival after coronary artery bypass grafting (CABG). Differences in survival by race have not been examined.

Methods: A retrospective cohort study was conducted of CABG patients between 2002 and 2011. Long-term survival was compared in patients with and without COPD and stratified by race. Hazard ratios (HR) and 95% confidence intervals (CI) were computed using a Cox regression model.

Results: A total of 984 (20%) patients had COPD (black n = 182; white n = 802) at the time of CABG (N = 4,801). The median follow-up for study participants was 4.4 years. COPD was observed to be a statistically significant predictor of decreased survival independent of race following CABG (no COPD: HR = 1.0; white COPD: adjusted HR = 1.9, 95% CI = 1.7–2.3; black COPD: adjusted HR = 1.6, 95% CI = 1.1–2.2).

Conclusion: Contrary to the expected increased risk of mortality among black COPD patients in the general population, a similar survival disadvantage was not observed in our CABG population.

Early-onset chronic obstructive pulmonary disease is associated with female sex, maternal factors, and African American race in the COPDGene Study

RATIONALE

The characterization of young adults who develop late-onset diseases may augment the detection of novel genes and promote new pathogenic insights.

METHODS

We analyzed data from 2,500 individuals of African and European ancestry in the COPDGene Study. Subjects with severe, early-onset chronic obstructive pulmonary disease (COPD) (n=70, age < 55 yr, FEV1 < 50% predicted) were compared with older subjects with COPD (n =306, age >64 yr, FEV1 <50% predicted).

MEASUREMENTS AND MAIN RESULTS

Subjects with severe, early-onset COPD were predominantly females (66%), P =0.0004. Proportionally,early-onset COPD was seen in 42% (25 of 59) of African Americans versus 14% (45 of 317) of non-Hispanic whites, P <0.0001. Other risk factors included current smoking (56 vs. 17%, P < 0.0001) and self-report of asthma (39 vs. 25%, P =0.008). Maternal smoking (70 vs. 44%, P=0.0001) and maternal COPD (23 vs.12%, P=0.03) were reported more commonly in subjects with early-onset COPD. Multivariable regression analysis found association with African American race, odds ratio (OR), 7.5 (95% confidence interval [CI], 2.3–24; P ¼=0.0007); maternal COPD, OR, 4.7 (95% CI,1.3–17; P=0.02); female sex, OR, 3.1 (95% CI, 1.1–8.7; P=0.03); and each pack-year of smoking, OR, 0.98 (95% CI, 0.96–1.0; P ¼ 0.03).

CONCLUSIONS

These observations support the hypothesis that severe, early-onset COPD is prevalent in females and is influenced by maternal factors. Future genetic studies should evaluate (1) gene-by-sex interactions to address sex-specific genetic contributions and (2) gene-by-race interactions.

Racial differences in quality of life in patients with COPD

BACKGROUND

Although COPD is associated with significant health-related quality-of-life (HRQL) impairment, factors influencing HRQL in patients with COPD are not well understood, particularly in African Americans. We hypothesized that HRQL in COPD differs by race and sought to identify factors associated with those differences.

METHODS

We analyzed 224 African American and 1,049 Caucasian subjects with COPD enrolled in the COPDGene (Genetic Epidemiology of COPD) Study whose conditions were classified as GOLD (Global Initiative for Chronic Obstructive Lung Disease) stages I to IV. HRQL and symptoms were compared using the St. George Respiratory Questionnaire (SGRQ) and the modified Medical Research Council Dyspnea (MMRC) scale. We constructed a mixed-effects linear regression model for SGRQ score.

RESULTS

African Americans were younger and reported fewer pack-years of smoking, more current smoking, and less attained education than Caucasians; MMRC scores were higher (P = .02) as were SGRQ scores (mean score difference, 8.4; P < .001). In a general linear model of SGRQ total score after adjusting for factors such as age, sex, and pack-years of smoking, SGRQ total score was similar for African Americans and Caucasians who reported no COPD exacerbations in the prior year. However, for subjects with exacerbations, SGRQ total score was increased to a greater relative extent for African Americans than for Caucasians (1.89 points for each exacerbation, P = .006). For hospitalized exacerbations, the effect on SGRQ total score also was greater for African Americans (4.19 points, P = .04). Furthermore, a larger percentage of African Americans reported having had at least one exacerbation that required hospitalization in the prior year (32% vs 16%, P < .001).

CONCLUSION

In analyses that account for other variables that affect quality of life, HRQL is similar for African Americans and Caucasians with COPD without exacerbations but worse for African Americans who experience exacerbations, particularly hospitalized exacerbations.

The impact of self-identified race on epidemiologic studies of gene expression

Although population differences in gene expression have been established, the impact on differential gene expression studies in large populations is not well understood. We describe the effect of self-reported race on a gene expression study of lung function in asthma. We generated gene expression profiles for 254 young adults (205 non-Hispanic whites and 49 African Americans) with asthma on whom concurrent total RNA derived from peripheral blood CD4(+) lymphocytes and lung function measurements were obtained. We identified four principal components that explained 62% of the variance in gene expression. The dominant principal component, which explained 29% of the total variance in gene expression, was strongly associated with self-identified race (P<10(-16)). The impact of these racial differences was observed when we performed differential gene expression analysis of lung function. Using multivariate linear models, we tested whether gene expression was associated with a quantitative measure of lung function: pre-bronchodilator forced expiratory volume in one second (FEV(1)). Though unadjusted linear models of FEV(1) identified several genes strongly correlated with lung function, these correlations were due to racial differences in the distribution of both FEV(1) and gene expression, and were no longer statistically significant following adjustment for self-identified race. These results suggest that self-identified race is a critical confounding covariate in epidemiologic studies of gene expression and that, similar to genetic studies, careful consideration of self-identified race in gene expression profiling studies is needed to avoid spurious association.

Recent trends and geographic patterns of the burden of disease attributable to smoking

PURPOSE

Quality-adjusted life-years (QALYs) use a single number to provide an assessment of the overall health burden of diseases associated both with mortality and morbidity. This study examined the trend and geographic variation of the burden of smoking by calculating smoking-related QALYs lost from 1993 to 2008 for the US adults and individual states.

METHODS

Population health-related quality of life scores were estimated from the 1993 to 2008 Behavioral Risk Factor Surveillance System. The smoking-related QALYs lost are the sum of QALYs lost due to morbidity and future QALYs lost in expected life years due to premature deaths (mortality).

RESULTS

From 1993 to 2008, the percent of US adults who smoked declined from 22.7% to 18.5%, but the smoking-related QALYs lost were relatively stable at 0.0438 QALYs lost per population. Although smoking contributed more QALYs lost for men (0.0535) than for women (0.0339), smoking-related QALYs lost decreased by 2.5% for men but increased by 12.6% for women. Kentucky, Oklahoma, Mississippi, West Virginia, and Tennessee had the most smoking-related QALYs lost wheras Utah, California, Connecticut, Minnesota, and Hawaii had the least QALYs lost. The state tobacco tax rate was strongly and negatively associated with both the percent smoked (r = -0.60) and QALYs lost (r = -0.54), as well as the percentage change in both.

CONCLUSIONS

This analysis quantified the overall burden of smoking for the nation and individual states from 1993 to 2008. Such data might assist in providing specified quantitative targets for the Healthy People 2020 smoking-related health objectives and for tracking changes on a yearly basis.

HIV and COPD: impact of risk behaviors and diseases on quality of life

PURPOSE

Smoking worsens quality of life among HIV-infected individuals, but it remains unclear if this association is related simply to smoking or to chronic obstructive pulmonary disease (COPD), the end-organ disease caused by smoking.

METHODS

Using cross-sectional data from the AIDS Linked to the Intravenous Experience study, we determined the independent effects of smoking, HIV and COPD assessed using the Medical Outcome Studies-HIV questionnaire.

RESULTS

Of 973 participants, 287 (29.5%) were HIV infected and 151 (15.5%) had spirometry-defined obstruction. Eight hundred and thirty-four (85.7%) were current smokers with 23.3 mean pack-years history. HIV infection was independently associated with reduced physical and mental health. COPD was associated with a trend toward worse physical health (-1.48 units; 95%CI -3.33 to 0.38; p = 0.12) and was independently associated with worse mental health (-2.43 units; 95%CI -4.22 to -0.64; p < 0.01). After accounting for COPD and other covariates, smoking was not associated with changes in physical or mental health.

CONCLUSIONS

The presence of COPD, rather than smoking, is associated with worse quality of life independent of HIV infection. Diagnosis and management of COPD in former or current smokers with or at risk for HIV may further improve quality of life.