Changes in Spirometry Interpretative Strategies: Implications for Classifying COPD and Predicting Exacerbations.

BACKGROUND: Recent guidelines for spirometry interpretation recommend both race-neutral reference equations and use of z score thresholds to define severity of airflow obstruction. RESEARCH QUESTION: How does the transition from race-specific to race-neutral equations impact severity classifications for patients with COPD when using % predicted vs z score thresholds, and do changes in severity correspond to clinical risk? STUDY DESIGN AND METHODS: This retrospective cohort study included Black and White patients with COPD and available spirometry from the Johns Hopkins Health System. Global Lung Function Initiative (GLI) 2012 (race-specific) equations and GLI Global (race-neutral) equations were used to determine FEV1 % predicted and z score values. Patients were classified as having mild, moderate, or severe disease according to % predicted or z score thresholds. Associations between a change in severity classification from race-specific to race-neutral with COPD exacerbations and all-cause hospitalizations were evaluated using logistic regression. RESULTS: This cohort included 13,324 patients, of whom 9,232 patients (69.3%) were White (mean age, 65.7 years) and 4,092 patients (30.7%) were Black (mean age, 61.1 years). More Black than White patients showed a change in severity classification between approaches when using % predicted thresholds (20.2% vs 6.1%; P < .001), but not with z score thresholds (12.6% vs 12.3%; P = .68). An increased severity classification with a race-neutral approach was associated with increased risk of exacerbation when using z score thresholds (OR, 2.34; 95% CI, 1.51-3.63), but not when using % predicted thresholds (OR, 1.08; 95% CI, 0.61-1.93). A decreased severity classification with a race-neutral approach was associated with lower risk of exacerbation with both % predicted (OR, 0.49; 95% CI, 0.28-0.87) and z score (OR 0.67; 95% CI, 0.50-0.90) thresholds. INTERPRETATION: The proportions of Black and White individuals reclassified were similar with z score thresholds, and changes in severity corresponded to clinical risk with z scores. These results support recent recommendations for use of race-neutral equations and z score thresholds for spirometry interpretation.

FEV1Q: a race-neutral approach to assessing lung function.

BACKGROUND: Forced expiratory volume in 1 s quotient (FEV1Q) is a simple approach to spirometry interpretation that compares measured lung function to a lower boundary. This study evaluated how well FEV1Q predicts survival compared with current interpretation methods and whether race impacts FEV1Q. METHODS: White and Black adults with complete spirometry and mortality data from the National Health and Nutrition Examination Survey (NHANES) III and the United Network for Organ Sharing (UNOS) database for lung transplant referrals were included. FEV1Q was calculated as FEV1 divided by 0.4 L for females or 0.5 L for males. Cumulative distributions of FEV1 were compared across races. Cox proportional hazards models tested mortality risk from FEV1Q adjusting for age, sex, height, smoking, income and among UNOS individuals, referral diagnosis. Harrell's C-statistics were compared between absolute FEV1, FEV1Q, FEV1/height2, FEV1 z-scores and FEV1 % predicted. Analyses were stratified by race. RESULTS: Among 7182 individuals from NHANES III and 7149 from UNOS, 1907 (27%) and 991 (14%), respectively, were Black. The lower boundary FEV1 values did not differ between Black and White individuals in either population (FEV1 first percentile difference ≤0.01 L; p>0.05). Decreasing FEV1Q was associated with increasing hazard ratio (HR) for mortality (NHANES III HR 1.33 (95% CI 1.28-1.39) and UNOS HR 1.18 (95% CI 1.12-1.23)). The associations were not confounded nor modified by race. Discriminative power was highest for FEV1Q compared with alternative FEV1 approaches in both Black and White individuals. CONCLUSIONS: FEV1Q is an intuitive and simple race-neutral approach to interpreting FEV1 that predicts survival better than current alternative methods.

Advancing assessment of asthma control with a composite tool: The Asthma Impairment and Risk Questionnaire.

BACKGROUND: National and international asthma guidelines and reports do not include control tools that combine impairment assessment with exacerbation history in one instrument. OBJECTIVE: To analyze the performance of the composite Asthma Impairment and Risk Questionnaire (AIRQ) in assessing both domains of control and predicting exacerbation risk compared with the Global Initiative for Asthma (GINA) 4-question symptom control tool (GINA SCT), Asthma Control Test (ACT), and physician expert opinion (EO) informed by GINA SCT responses and appraisal of GINA-identified risk factors for poor asthma outcomes. METHODS: Multivariable logistic regressions evaluated AIRQ and GINA SCT as predictors of ACT. McNemar's test compared the proportion of patients categorized at baseline as completely or well-controlled by each assessment but with current impairment or previous-year and subsequent-year exacerbations. RESULTS: The analysis included 1064 patients aged 12 years or older; mean (SD) age 43.8 years (19.3); 70% female; 79% White; and 6% Hispanic or Latino. AIRQ and GINA SCT were highly predictive of ACT well-controlled vs not well-controlled and very poorly controlled (receiver operator characteristic area under curve AIRQ = 0.90, GINA SCT = 0.86, P = .03 AIRQ vs GINA SCT) and ACT very poorly controlled vs well-controlled and not well-controlled asthma (receiver operator characteristic area under curve AIRQ = 0.91, GINA SCT = 0.87, P = .01 AIRQ vs GINA SCT). AIRQ rated fewer patients as having completely or well-controlled asthma who had current impairment (P < .01) or with previous-year and subsequent-year exacerbations (P < .001) than did GINA SCT, ACT, and EO. CONCLUSION: AIRQ performs better in assessing both domains of current control and predicting exacerbation risk than do control tools and EO informed by GINA SCT and risk factors for poor asthma outcomes.

Assessing meaningful change in the Asthma Impairment and Risk Questionnaire.

BACKGROUND: The Asthma Impairment and Risk Questionnaire (AIRQ) is a 10-item, yes/no, equally weighted control tool. Lower scores indicate better control. Moreover, 7 impairment items reflect previous 2-week symptoms, and 3 risk items assess previous 12-month exacerbations. The Follow-up AIRQ for use between annual assessments has a 3-month recall period for exacerbation items. OBJECTIVE: To evaluate the responsiveness of the AIRQ over time and identify a minimal important difference (MID). METHODS: The AIRQ longitudinal study data were analyzed from patients with asthma aged 12 years and older. Anchor-based methods assessed differences in AIRQ scores relative to Patient Global Impression of Change, the accepted MIDs for St. George's Respiratory Questionnaire and Asthma Control Test, and exacerbation occurrence over 12 months. Baseline and 12-month data reflected 12-month recall AIRQ scores; Follow-up AIRQ scores were used for 3-, 6-, and 9-month analyses. RESULTS: A total of 1070 patients were included. The Patient Global Impression of Change rating of "much improved" was associated with AIRQ mean score changes from baseline to months 3, 6, 9, and 12 of -2.0, -1.9, -1.9, and -1.8, respectively. The mean AIRQ score change among patients who met the St. George's Respiratory Questionnaire MID (≥4-point decrease) was -1.8 at 6 and 12 months. The AIRQ mean scores decreased from baseline by -2.2 to -2.5 points at months 3, 6, 9, and 12 for patients who met the Asthma Control Test MID (≥ 3-point increase). A 2-point higher baseline AIRQ score was associated with a 1.7 odds ratio of 12-month exacerbation occurrence (95% CI, 1.53-1.89). CONCLUSION: A change score of 2 is recommended as the AIRQ MID.

Exebacase in Addition to Standard-of-Care Antibiotics for Staphylococcus aureus Bloodstream Infections and Right-Sided Infective Endocarditis: A Phase 3, Superiority-Design, Placebo-Controlled, Randomized Clinical Trial (DISRUPT).

BACKGROUND: Novel treatments are needed for Staphylococcus aureus bacteremia, particularly for methicillin-resistant S. aureus (MRSA). Exebacase is a first-in-class antistaphylococcal lysin that is rapidly bactericidal and synergizes with antibiotics. METHODS: In DISRUPT, a superiority-design phase 3 study, patients with S. aureus bacteremia/endocarditis were randomly assigned to receive a single dose of IV exebacase or placebo in addition to standard-of-care antibiotics. The primary efficacy outcome was clinical response at Day 14 in the MRSA population. RESULTS: A total of 259 patients were randomized before the study was stopped for futility based on the recommendation of the unblinded Data Safety Monitoring Board. Clinical response rates at Day 14 in the MRSA population (n = 97) were 50.0% (exebacase + antibiotics; 32/64) vs. 60.6% (antibiotics alone; 20/33) (P = 0.392). Overall, rates of adverse events were similar across groups. No adverse events of hypersensitivity related to exebacase were reported. CONCLUSIONS: Exebacase + antibiotics failed to improve clinical response at Day 14 in patients with MRSA bacteremia/endocarditis. This result was unexpected based on phase 2 data that established proof-of-concept for exebacase + antibiotics in patients with MRSA bacteremia/endocarditis. In the antibiotics alone group, the clinical response rate was higher than that seen in phase 2. Heterogeneity within the study population and a relatively small sample size in either the phase 2 or phase 3 studies may have increased the probability of imbalances in the multiple components of Day 14 clinical outcome. This study provides lessons for future superiority studies in S. aureus bacteremia/endocarditis.

Diffusing Capacity as a Predictor of Hospitalizations in a Clinical Cohort of Chronic Obstructive Pulmonary Disease.

Rationale: Chronic obstructive pulmonary disease (COPD) hospitalizations are a major burden on patients. Diffusing capacity of the lung for carbon monoxide (DlCO) is a potential predictor that has not been studied in large cohorts. Objectives: This study used electronic health record data to evaluate whether clinically obtained DlCO predicts COPD hospitalizations. Methods: We performed time-to-event analyses of individuals with COPD and DlCO measurements from the Johns Hopkins COPD Precision Medicine Center of Excellence. Cox proportional hazard methods were used to model time from DlCO measurement to first COPD hospitalization and composite first hospitalization or death, adjusting for age, sex, race, body mass index, smoking status, forced expiratory volume in 1 second (FEV1), history of prior COPD hospitalization, and comorbidities. To identify the utility of including DlCO in risk models, area under the receiver operating curve (AUC) values were calculated for models with and without DlCO. Results were externally validated in a separate analogous cohort. Results: Of 2,793 participants, 368 (13%) had a COPD hospitalization within 3 years. In adjusted analyses, for every 10% decrease in DlCO% predicted, risk of COPD hospitalization increased by 10% (hazard ratio, 1.1; 95% confidence interval, 1.1-1.2; P < 0.001). Similar associations were observed for COPD hospitalizations or death. The model including demographics, comorbidities, FEV1, DlCO, and prior COPD hospitalizations performed well, with an AUC of 0.85 and an AUC of 0.84 in an external validation cohort. Conclusions: Diffusing capacity is a strong predictor of COPD hospitalizations in a clinical cohort of individuals with COPD, independent of airflow obstruction and prior hospitalizations. These findings support incorporation of DlCO in risk assessment of patients with COPD.

Early Evidence of Chronic Obstructive Pulmonary Disease Obscured by Race-Specific Prediction Equations.

Rationale: The identification of early chronic obstructive pulmonary disease (COPD) is essential to appropriately counsel patients regarding smoking cessation, provide symptomatic treatment, and eventually develop disease-modifying treatments. Disease severity in COPD is defined using race-specific spirometry equations. These may disadvantage non-White individuals in diagnosis and care. Objectives: Determine the impact of race-specific equations on African American (AA) versus non-Hispanic White individuals. Methods: Cross-sectional analyses of the COPDGene (Genetic Epidemiology of Chronic Obstructive Pulmonary Disease) cohort were conducted, comparing non-Hispanic White (n = 6,766) and AA (n = 3,366) participants for COPD manifestations. Measurements and Main Results: Spirometric classifications using race-specific, multiethnic, and "race-reversed" prediction equations (NHANES [National Health and Nutrition Examination Survey] and Global Lung Function Initiative "Other" and "Global") were compared, as were respiratory symptoms, 6-minute-walk distance, computed tomography imaging, respiratory exacerbations, and St. George's Respiratory Questionnaire. Application of different prediction equations to the cohort resulted in different classifications by stage, with NHANES and Global Lung Function Initiative race-specific equations being minimally different, but race-reversed equations moving AA participants to more severe stages and especially between the Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage 0 and preserved ratio impaired spirometry groups. Classification using the established NHANES race-specific equations demonstrated that for each of GOLD stages 1-4, AA participants were younger, had fewer pack-years and more current smoking, but had more exacerbations, shorter 6-minute-walk distance, greater dyspnea, and worse BODE (body mass index, airway obstruction, dyspnea, and exercise capacity) scores and St. George's Respiratory Questionnaire scores. Differences were greatest in GOLD stages 1 and 2. Race-reversed equations reclassified 774 AA participants (43%) from GOLD stage 0 to preserved ratio impaired spirometry. Conclusions: Race-specific equations underestimated disease severity among AA participants. These effects were particularly evident in early disease and may result in late detection of COPD.

Bronchodilator response does not associate with asthma control or symptom burden among patients with poorly controlled asthma.

PURPOSE: The purpose of this study was to determine how four different definitions of bronchodilator response (BDR) relate to asthma control and asthma symptom burden in a large population of participants with poorly controlled asthma. PROCEDURES: We examined the baseline change in FEV1 and FVC in response to albuterol among 931 participants with poorly controlled asthma pooled from three clinical trials conducted by the American Lung Association - Airways Clinical Research Centers. We defined BDR based on four definitions and analyzed the association of each with asthma control as measured by the Asthma Control Test or Asthma Control Questionnaire, and asthma symptom burden as measured by the Asthma Symptom Utility Index. MAIN FINDINGS: A BDR was seen in 31-42% of all participants, depending on the definition used. There was good agreement among responses (kappa coefficient 0.73 to 0.87), but only 56% of participants met all four definitions for BDR. A BDR was more common in men than women, in Blacks compared to Whites, in non-smokers compared to smokers, and in non-obese compared to obese participants. Among those with poorly controlled asthma, 35% had a BDR compared to 25% of those with well controlled asthma, and among those with a high symptom burden, 34% had a BDR compared to 28% of those with a low symptom burden. After adjusting for age, sex, height, race, obesity and baseline lung function, none of the four definitions was associated with asthma control or symptom burden. CONCLUSION: A BDR is not associated with asthma control or symptoms in people with poorly controlled asthma, regardless of the definition of BDR used. These findings question the clinical utility of a BDR in assessing asthma control and symptoms.

"It's a cause I believe in": factors motivating participation and engagement in longitudinal, respiratory-focused research studies.

BACKGROUND: Key to the success of any prospective cohort study is the effective recruitment and retention of participants, but the specific factors that influence younger adults of the Millennial generation to participate in research are not well-understood. The objective of this qualitative study was to identify factors that motivated participation and engagement in longitudinal research studies focused on respiratory health among a diverse group of young adults. METHODS: We conducted qualitative, semi-structured interviews with 50 younger adult participants (aged 25-35 years) regarding factors influencing their participation in longitudinal research studies. Thematic analysis was used to develop, organize, and tabulate the frequency of key themes. In exploratory analyses, we examined for patterns in the distribution of key themes across racial, ethnic, or socioeconomic groups. RESULTS: Participants identified several key themes that affected their willingness to participate in longitudinal studies. These included the health-related benefits generated by research (both to the individual and to society at-large), factors related to the institution and study team conducting the research, concerns regarding unethical and/or unrepresentative study design, and barriers to participation in research. Certain factors may be more impactful to underrepresented groups, including concerns regarding data privacy and confidentiality. CONCLUSIONS: In this diverse group of younger adults, we identified specific factors that motivated participation and predicted high engagement in longitudinal research studies focused on respiratory health. Implementing and integrating these factors into study protocols may improve recruitment and retention, including among participants who are historically underrepresented in research.

Comprehension by Caregivers and Adolescents of Clinical Trial Information Delivered via Multimedia Video Versus Conventional Practice: Nonrandomized Controlled Trial.

BACKGROUND: Research participants often misunderstand the required elements of informed consent information, whether provided in written or oral format. Informed consent instruments with embedded evidence-based learning theory principles administered in multimedia electronic formats may improve comprehension and retention. OBJECTIVE: This study aims to determine whether study information comprehension and retention using an interactive multimedia video consent process was noninferior to comprehension and retention after an in-person face-to-face interaction with a conventional written consent document for caregivers and adolescents enrolled in a clinical trial. METHODS: Participants were caregivers and children aged 12 to 17 years who were enrolled in a clinical trial of asthma treatment. Consent information was presented as a multimedia web-based video consent interaction or as a conventional written consent document with in-person interaction between the prospective participants and the study staff. The trial used a parallel nonrandomized noninferiority design that compared the 2 consent methods. Caregivers and adolescents completed a 17-item open-ended comprehension questionnaire (score range 17-51) at enrollment and at the end of the study 20 weeks later. Comprehension and retention were compared between the consent formats. Noninferiority was established if the 95% CI upper bound of the difference in scores (conventional format minus web-based) was less than the noninferiority margin of 2.4; superiority was established if the upper bound of the CI was <0. RESULTS: In total, 54 caregiver and adolescent dyads completed the interactive multimedia web-based video consent, and 25 dyads completed the conventional consent. Overall, 33% (26/79) of all adolescents were Black, 57% (45/79) were male, and 61% (48/79) had a household income of

The Asthma Impairment and Risk Questionnaire enhances the assessment of asthma control.

BACKGROUND: Asthma control is often overestimated in routine practice, and despite advances in the understanding of immunopathology and the availability of new precision therapies, the burden of disease remains unacceptably high. OBJECTIVE: To compare the performance of the Asthma Impairment and Risk Questionnaire (AIRQ) with patient and physician assessments and the Asthma Control Test (ACT) in identifying asthma control. METHODS: Baseline data from a longitudinal study of the AIRQ were analyzed. Patients with asthma in the United States aged 12 years and older followed in 24 specialty practices and 1 specialty-affiliated primary care clinic were enrolled between May and November 2019. At entry, participants completed AIRQ and ACT, and participants and physicians completed 5-point Likert scale assessments of control. RESULTS: A total of 1112 participants were enrolled (mean [SD] age = 43.9 [19.3] years, 70% of the female sex, 78% White). Overall, 62% of participants rated themselves as well- or completely controlled, and 54% were rated comparably by physicians. The ACT classified 49% of participants as well-controlled, with 35% similarly categorized by AIRQ. Previous-year exacerbations were experienced by 32% of participants who self-rated as well- or completely controlled, 30% who were rated as well- or completely controlled by physicians, and 29% assessed as well-controlled by ACT, but only 15% of those classified as well-controlled by AIRQ. CONCLUSION: The burden of asthma is substantial in patients cared for by asthma specialists, and asthma control is overestimated by patients, physicians, and the symptom-based ACT. The AIRQ assesses risk in addition to symptom control and may serve to improve asthma control determination by assessing previous exacerbations.

Efficacy and tolerability of zinc acetate for treatment of chronic refractory cough: pilot randomised futility trial.

Background: Cough is the most reported symptom in the United States, with chronic refractory cough representing significant morbidity to patients. Zinc acetate may have beneficial effects in the cough reflex pathway. We sought to assess the safety and efficacy of zinc acetate in the management of chronic refractory cough. Study design and methods: This was a randomised, placebo-controlled, parallel-design pilot trial of individuals with chronic refractory cough. The effects of 6 weeks of zinc acetate versus placebo on quality of life and symptoms as measured by the Cough Quality-of-Life Questionnaire (CQLQ), Leicester Cough Questionnaire (LCQ), cough visual analogue score (C-VAS) and Global Assessment of Change in Cough (GACC) scores were evaluated. A futility analysis plan with a one-sided 80% confidence interval was used to compare treatment effect to published minimum clinically important differences (MCID) for each outcome. Results: 34 participants, 17 in each group, were enrolled and randomised. Participants were primarily white females with moderate-severe cough. Participants assigned to zinc acetate had a significant increase in serum zinc levels after 6 weeks, while those assigned to placebo did not. Both groups showed improvement in CQLQ, LCQ, C-VAS and GACC scores, but the treatment effects of zinc acetate versus placebo were small with confidence intervals that did not include the MCIDs. Interpretation: We observed no benefit of zinc therapy over placebo on cough symptoms or quality of life and conclude that larger trials of zinc for chronic cough are not warranted.

Race and Ethnicity in Pulmonary Function Test Interpretation: An Official American Thoracic Society Statement.

Current American Thoracic Society (ATS) standards promote the use of race and ethnicity-specific reference equations for pulmonary function test (PFT) interpretation. There is rising concern that the use of race and ethnicity in PFT interpretation contributes to a false view of fixed differences between races and may mask the effects of differential exposures. This use of race and ethnicity may contribute to health disparities by norming differences in pulmonary function. In the United States and globally, race serves as a social construct that is based on appearance and reflects social values, structures, and practices. Classification of people into racial and ethnic groups differs geographically and temporally. These considerations challenge the notion that racial and ethnic categories have biological meaning and question the use of race in PFT interpretation. The ATS convened a diverse group of clinicians and investigators for a workshop in 2021 to evaluate the use of race and ethnicity in PFT interpretation. Review of evidence published since then that challenges current practice and continued discussion concluded with a recommendation to replace race and ethnicity-specific equations with race-neutral average reference equations, which must be accompanied with a broader re-evaluation of how PFTs are used to make clinical, employment, and insurance decisions. There was also a call to engage key stakeholders not represented in this workshop and a statement of caution regarding the uncertain effects and potential harms of this change. Other recommendations include continued research and education to understand the impact of the change, to improve the evidence for the use of PFTs in general, and to identify modifiable risk factors for reduced pulmonary function.

Relationship Between Asthma Control as Measured by the Asthma Impairment and Risk Questionnaire (AIRQ) and Patient Perception of Disease Status, Health-Related Quality of Life, and Treatment Adherence.

Purpose: Critical asthma outcomes highlighted in clinical guidelines include asthma-related quality of life, asthma exacerbations, and asthma control. An easy-to-implement measure of asthma control that assesses both symptom impairment and exacerbation risk and reflects the impact of asthma on patients' lives is lacking. Hence, the objective of this study was to assess the Asthma Impairment and Risk Questionnaire (AIRQ®) construct validity relative to patient self-perception of asthma status and validated disease-specific patient-reported outcome (PRO) measures. Patients and methods: Baseline data were analyzed from patients (aged ≥ 12 years) with asthma participating in a 12-month observational study assessing the ability of AIRQ to predict exacerbations. At entry, patients completed a sociodemographic questionnaire, AIRQ, 3 questions addressing self-perceived asthma status, Saint George's Respiratory Questionnaire (SGRQ), mini-Asthma Quality of Life Questionnaire (AQLQ), and Adult Asthma Adherence Questionnaire (AAAQ). Descriptive statistics were calculated for demographic and clinical characteristics. AIRQ construct validity was evaluated by assessing correlations between total AIRQ score and patient self-assessments, SGRQ, mini-AQLQ, and AAAQ scores. Comparisons of SGRQ, mini-AQLQ, and AAAQ total and component/domain scores by AIRQ control category were performed using general linear models and Scheffe's post hoc adjustments for pairwise comparisons. Results: A total of 1112 patients were enrolled: 70% female, 78% White, mean (standard deviation) age 43.9 (19.5) years. There were highly significant correlations between AIRQ score and patient self-perception of overall control (r = 0.69; p < 0.001), total SGRQ (r = 0.74, p < 0.001), and mini-AQLQ (r = -0.78, p < 0.001) scores. As AIRQ control category worsened, so did total and domain SGRQ, mini-AQLQ, and AAAQ impediment-to-inhaled-corticosteroid-adherence scores (all pairwise comparisons p < 0.001). Conclusion: Findings demonstrate the construct validity of AIRQ relative to patient self-perception of asthma status, disease-specific PRO measures, and treatment adherence barriers. AIRQ can be a useful instrument to raise awareness of the unrecognized impacts of asthma on patients' lives.

Diffusing Capacity and Mortality in Chronic Obstructive Pulmonary Disease.

Rationale: Chronic obstructive pulmonary disease (COPD) mortality risk is often estimated using the BODE (body mass index, obstruction, dyspnea, exercise capacity) index, including body mass index, forced expiratory volume in 1 second, dyspnea score, and 6-minute walk distance. Diffusing capacity of the lung for carbon monoxide (DlCO) is a potential predictor of mortality that reflects physiology distinct from that in the BODE index. Objectives: This study evaluated DlCO as a predictor of mortality using participants from the COPDGene study. Methods: We performed time-to-event analyses of individuals with COPD (former or current smokers with forced expiratory volume in 1 second/forced vital capacity < 0.7) and DlCO measurements from the COPDGene phase 2 visit. Cox proportional hazard methods were used to model survival, adjusting for age, sex, pack-years, smoking status, BODE index, computed tomography (CT) percent emphysema (low attenuation areas below -950 Hounsfield units), CT airway wall thickness, and history of cardiovascular or kidney diseases. C statistics for models with DlCO and BODE scores were used to compare discriminative accuracy. Results: Of 2,329 participants, 393 (16.8%) died during the follow-up period (median = 4.9 yr). In adjusted analyses, for every 10% decrease in DlCO percent predicted, mortality increased by 28% (hazard ratio = 1.28; 95% confidence interval, 1.17-1.41, P < 0.001). When compared with other clinical predictors, DlCO percent predicted performed similarly to BODE (C statistic DlCO = 0.68; BODE = 0.70), and the addition of DlCO to BODE improved its discriminative accuracy (C statistic = 0.71). Conclusions: Diffusing capacity, a measure of gas transfer, strongly predicted all-cause mortality in individuals with COPD, independent of BODE index and CT evidence of emphysema and airway wall thickness. These findings support inclusion of DlCO in prognostic models for COPD.

Heterogeneity of Lung Function Phenotypes in Sarcoidosis: Role of Race and Sex Differences.

Rationale: Historically, sarcoidosis was described as a restrictive lung disease, but several alternative phenotypes of pulmonary function have been observed. Pulmonary function phenotypes in sarcoidosis may represent different clinical and/or molecular phenotypes. Objectives: To characterize the prevalence of different pulmonary function phenotypes in a large and diverse sarcoidosis cohort from a tertiary care referral center. Methods: We identified individuals seen between 2005-2015 with a confirmed diagnosis of sarcoidosis. Data were collected from the first pulmonary function test (PFT) performed at our institution which included spirometry and diffusing capacity of the lung for carbon monoxide (DlCO). Demographics and clinical data were collected. Chi-squared analyses and multiple linear regressions were done to assess statistical differences and associations. Global Lung Function Initiative equations were used to calculate percent predicted measurements for spirometry and DlCO. Results: Of 602 individuals with sarcoidosis, 93% (562) had pulmonary involvement, 64% (385) were female, and 57% (341) were Black. Of those with pulmonary involvement, 56% had abnormal pulmonary function. Lung function impairment phenotypes included: 47% restriction, 22% obstruction, 15% isolated reduction in DlCO, and 16% combined obstructive restrictive phenotype. Restriction was the most common PFT phenotype among Black individuals (41%), while no lung impairment was most common among White individuals (66%) (P < 0.001). Males more frequently had obstruction (19%) compared with females (9%) P = 0.001, and females had more restriction (30%) compared with males (21%) P = 0.031. Conclusions: Among individuals with sarcoidosis and pulmonary function impairment, less than half demonstrated a restrictive phenotype. There were significant differences in pulmonary function phenotypes by race and sex.