Rationale: Radiologic pattern has been shown to predict survival in patients with fibrosing interstitial lung disease. The additional prognostic value of fibrosis extent by quantitative computed tomography (CT) is unknown. Objectives: We hypothesized that fibrosis extent provides information beyond visually assessed CT pattern that is useful for outcome prediction. Methods: We performed a retrospective analysis of chest CT, demographics, longitudinal pulmonary function, and transplantation-free survival among participants in the Pulmonary Fibrosis Foundation Patient Registry. CT pattern was classified visually according to the 2018 usual interstitial pneumonia criteria. Extent of fibrosis was objectively quantified using data-driven textural analysis. We used Kaplan-Meier plots and Cox proportional hazards and linear mixed-effects models to evaluate the relationships between CT-derived metrics and outcomes. Results: Visual assessment and quantitative analysis were performed on 979 enrollment CT scans. Linear mixed-effect modeling showed that greater baseline fibrosis extent was significantly associated with the annual rate of decline in forced vital capacity. In multivariable models that included CT pattern and fibrosis extent, quantitative fibrosis extent was strongly associated with transplantation-free survival independent of CT pattern (hazard ratio, 1.04; 95% confidence interval, 1.04-1.05; P < 0.001; C statistic = 0.73). Conclusions: The extent of lung fibrosis by quantitative CT is a strong predictor of physiologic progression and survival, independent of visually assessed CT pattern.
Rationale: Bronchopulmonary dysplasia (BPD) is the most common long-term complication of prematurity. Although socioeconomic status is associated with BPD morbidities, the drivers of this association are poorly understood. In the United States, ambient air pollution (AAP) exposure is linked to both race/ethnicity and socioeconomic status. Furthermore, AAP exposure is known to have a detrimental effect on respiratory health in children. Objectives: To assess if AAP exposure is linked to BPD morbidity in the outpatient setting. Methods: Participants with BPD were recruited from outpatient clinics at Johns Hopkins University and the Children's Hospital of Philadelphia between 2008 and 2021 (N = 800) and divided into low, moderate, and high AAP exposure groups, based on publicly available U.S. Environmental Protection Agency data. Clinical data were obtained by chart review and caregiver questionnaires. Results: Non-White race, home ventilator use, and lower median household income were associated with higher degrees of air pollution exposure. After adjustment for these factors, moderate and high air pollution exposure were associated with requiring systemic steroids (odds ratio, 1.78 and 2.17, respectively) compared with low air pollution. Similarly, high air pollution exposure was associated with emergency department visits (odds ratio, 1.59). Conclusions: This study demonstrates an association between AAP exposure and BPD morbidity after initial hospital discharge. AAP exposure was closely linked to race and median household income. As such, it supports the notion that AAP exposure may be contributing to health disparities in BPD outcomes. Further studies directly measuring exposure and establishing a link between biomarkers of exposure and outcomes are prerequisites to developing targeted interventions protecting this vulnerable population.
Rationale: Cardiopulmonary exercise testing (CPET) is the gold standard to evaluate exertional breathlessness, a common and disabling symptom. However, the interpretation of breathlessness responses to CPET is limited by a scarcity of normative data. Objectives: We aimed to develop normative reference equations for breathlessness intensity (Borg 0-10 category ratio) response in men and women aged ⩾40 years during CPET, in relation to power output (watts), oxygen uptake, and minute ventilation. Methods: Analysis of ostensibly healthy people aged ⩾40 years undergoing symptom-limited incremental cycle CPET (10 W/min) in the CanCOLD (Canadian Cohort Obstructive Lung Disease) study. Participants had smoking histories <5 pack-years and normal lung function and exercise capacity. The probability of each Borg 0-10 category ratio breathlessness intensity rating by power output, oxygen uptake, and minute ventilation (as an absolute or a relative value [percentage of predicted maximum]) was predicted using ordinal multinomial logistic regression. Model performance was evaluated by fit, calibration, and discrimination (C statistic) and externally validated in an independent sample (n = 86) of healthy Canadian adults. Results: We included 156 participants (43% women) from CanCOLD; the mean age was 65 (range, 42-91) years, and the mean body mass index was 26.3 (standard deviation, 3.8) kg/m2. Reference equations were developed for women and men separately, accounting for age and/or body mass. Model performance was high across all equations, including in the validation sample (C statistic for men = 0.81-0.92, C statistic for women = 0.81-0.96). Conclusions: Normative reference equations are provided to compare exertional breathlessness intensity ratings among individuals or groups and to identify and quantify abnormal breathlessness responses (scores greater than the upper limit of normal) during CPET.