@article {8097, title = {Discriminative Accuracy of FEV1:FVC Thresholds for COPD-Related Hospitalization and Mortality.}, journal = {JAMA}, volume = {321}, year = {2019}, month = {2019 06 25}, pages = {2438-2447}, abstract = {

Importance: According to numerous current guidelines, the diagnosis of chronic obstructive pulmonary disease (COPD) requires a ratio of the forced expiratory volume in the first second to the forced vital capacity (FEV1:FVC) of less than 0.70, yet this fixed threshold is based on expert opinion and remains controversial.

Objective: To determine the discriminative accuracy of various FEV1:FVC fixed thresholds for predicting COPD-related hospitalization and mortality.

Design, Setting, and Participants: The National Heart, Lung, and Blood Institute (NHLBI) Pooled Cohorts Study harmonized and pooled data from 4 US general population-based cohorts (Atherosclerosis Risk in Communities Study; Cardiovascular Health Study; Health, Aging, and Body Composition Study; and Multi-Ethnic Study of Atherosclerosis). Participants aged 45 to 102 years were enrolled from 1987 to 2000 and received follow-up longitudinally through 2016.

Exposures: Presence of airflow obstruction, which was defined by a baseline FEV1:FVC less than a range of fixed thresholds (0.75 to 0.65) or less than the lower limit of normal as defined by Global Lung Initiative reference equations (LLN).

Main Outcomes and Measures: The primary outcome was a composite of COPD hospitalization and COPD-related mortality, defined by adjudication or administrative criteria. The optimal fixed FEV1:FVC threshold was defined by the best discrimination for these COPD-related events as indexed using the Harrell C statistic from unadjusted Cox proportional hazards models. Differences in C statistics were compared with respect to less than 0.70 and less than LLN thresholds using a nonparametric approach.

Results: Among 24 207 adults in the pooled cohort (mean [SD] age at enrollment, 63 [10.5] years; 12 990 [54\%] women; 16 794 [69\%] non-Hispanic white; 15 181 [63\%] ever smokers), complete follow-up was available for 11 077 (77\%) at 15 years. During a median follow-up of 15 years, 3925 participants experienced COPD-related events over 340 757 person-years of follow-up (incidence density rate, 11.5 per 1000 person-years), including 3563 COPD-related hospitalizations and 447 COPD-related deaths. With respect to discrimination of COPD-related events, the optimal fixed threshold (0.71; C statistic for optimal fixed threshold, 0.696) was not significantly different from the 0.70 threshold (difference, 0.001 [95\% CI, -0.002 to 0.004]) but was more accurate than the LLN threshold (difference, 0.034 [95\% CI, 0.028 to 0.041]). The 0.70 threshold provided optimal discrimination in the subgroup analysis of ever smokers and in adjusted models.

Conclusions and Relevance: Defining airflow obstruction as FEV1:FVC less than 0.70 provided discrimination of COPD-related hospitalization and mortality that was not significantly different or was more accurate than other fixed thresholds and the LLN. These results support the use of FEV1:FVC less than 0.70 to identify individuals at risk of clinically significant COPD.

}, keywords = {Aged, Aged, 80 and over, Cohort Studies, Female, Forced Expiratory Volume, Hospitalization, Humans, Male, Middle Aged, Prognosis, Proportional Hazards Models, Pulmonary Disease, Chronic Obstructive, Risk Assessment, Vital Capacity}, issn = {1538-3598}, doi = {10.1001/jama.2019.7233}, author = {Bhatt, Surya P and Balte, Pallavi P and Schwartz, Joseph E and Cassano, Patricia A and Couper, David and Jacobs, David R and Kalhan, Ravi and O{\textquoteright}Connor, George T and Yende, Sachin and Sanders, Jason L and Umans, Jason G and Dransfield, Mark T and Chaves, Paulo H and White, Wendy B and Oelsner, Elizabeth C} } @article {9156, title = {Pooled Cohort Probability Score for Subclinical Airflow Obstruction.}, journal = {Ann Am Thorac Soc}, volume = {19}, year = {2022}, month = {2022 08}, pages = {1294-1304}, abstract = {

Early detection of chronic obstructive pulmonary disease (COPD) is a public health priority. Airflow obstruction is the single most important risk factor for adverse COPD outcomes, but spirometry is not routinely recommended for screening. To describe the burden of subclinical airflow obstruction (SAO) and to develop a probability score for SAO to inform potential detection and prevention programs. Lung function and clinical data were harmonized and pooled across nine U.S. general population cohorts. Adults with respiratory symptoms, inhaler use, or prior diagnosis of COPD or asthma were excluded. A probability score for prevalent SAO (forced expiratory volume in 1 second/forced vital capacity < 0.70) was developed via hierarchical group-lasso regularization from clinical variables in strata of sex and smoking status, and its discriminative accuracy for SAO was assessed in the pooled cohort as well as in an external validation cohort (NHANES [National Health and Nutrition Examination Survey] 2011-2012). Incident hospitalizations and deaths due to COPD (respiratory events) were defined by adjudication or administrative criteria in four of nine cohorts. Of 33,546 participants (mean age 52 yr, 54\% female, 44\% non-Hispanic White), 4,424 (13.2\%) had prevalent SAO. The incidence of respiratory events ( = 14,024) was threefold higher in participants with SAO versus those without (152 vs. 39 events/10,000 person-years). The probability score, which was based on six commonly available variables (age, sex, race and/or ethnicity, body mass index, smoking status, and smoking pack-years) was well calibrated and showed excellent discrimination in both the testing sample (C-statistic, 0.81; 95\% confidence interval [CI], 0.80-0.82) and in NHANES (C-statistic, 0.83; 95\% CI, 0.80-0.86). Among participants with predicted probabilities ⩾ 15\%, 3.2 would need to undergo spirometry to detect one case of SAO. Adults with SAO demonstrate excess respiratory hospitalization and mortality. A probability score for SAO using commonly available clinical risk factors may be suitable for targeting screening and primary prevention strategies.

}, keywords = {Adult, Female, Forced Expiratory Volume, Humans, Lung, Male, Middle Aged, Nutrition Surveys, Pulmonary Disease, Chronic Obstructive, Risk Factors, Spirometry, Vital Capacity}, issn = {2325-6621}, doi = {10.1513/AnnalsATS.202109-1020OC}, author = {Bhatt, Surya P and Balte, Pallavi P and Schwartz, Joseph E and Jaeger, Byron C and Cassano, Patricia A and Chaves, Paulo H and Couper, David and Jacobs, David R and Kalhan, Ravi and Kaplan, Robert and Lloyd-Jones, Donald and Newman, Anne B and O{\textquoteright}Connor, George and Sanders, Jason L and Smith, Benjamin M and Sun, Yifei and Umans, Jason G and White, Wendy B and Yende, Sachin and Oelsner, Elizabeth C} } @article {9902, title = {Low Lung Function Is Associated with High Population Attributable Fraction for Cardiovascular Mortality.}, journal = {Ann Am Thorac Soc}, volume = {22}, year = {2025}, month = {2025 Mar}, pages = {359-366}, abstract = {

Chronic lung diseases are associated with increased risk of mortality due to coronary heart disease (CHD). Nonetheless, the population attributable fraction (PAF) of lung function impairment relative to other established cardiovascular risk factors is unclear. To evaluate the PAF of low lung function for CHD mortality We harmonized and pooled lung function and clinical data across eight U.S. general population cohorts. Impaired lung function was defined as forced expiratory volume in 1 second (FEV) and/or forced vital capacity <= 95\% predicted on baseline spirometry. The association between CHD mortality and risk factors was assessed using cause-specific proportional hazards and Fine-Gray proportional subdistribution hazard models, treating non-CHD mortality as a competing risk. Models were adjusted for lung function as well as age, sex, race/ethnicity, educational attainment, body mass index, smoking status, pack-years of smoking, diabetes mellitus, high-density lipoprotein, and high low-density lipoprotein (>=130 mg/dl). PAF was calculated as the relative change in the average absolute risk of 10-year CHD mortality by elimination of lung function lower than 95\% predicted. Among 35,143 participants, 1,844 of 13,174 (14.0\%) deaths were due to CHD. Compared with percentage predicted FEV (FEVpp) > 95\%, the subdistribution adjusted hazard ratio for low FEVpp was 1.30 (95\% confidence interval, 1.18-1.44). The PAF for FEVpp <= 95\% was 12\%, ranking low FEV third on the list of PAF for CHD mortality, after hypertension and diabetes. Low FEVpp ranked second in the subgroup of active smokers (PAF 14\%), after hypertension. Low lung function, even in the range considered clinically normal, ranks high on the list of attributable risk factors for CHD mortality and should be considered in cardiovascular risk stratification.

}, keywords = {Adult, Aged, Coronary Disease, Female, Forced Expiratory Volume, Humans, Lung, Lung Diseases, Male, Middle Aged, Proportional Hazards Models, Risk Factors, Smoking, Spirometry, United States, Vital Capacity}, issn = {2325-6621}, doi = {10.1513/AnnalsATS.202407-715OC}, author = {Bhatt, Surya P and Wu, Chaoqi and Sun, Yifei and Balte, Pallavi P and Schwartz, Joseph E and Divo, Miguel J and Jaeger, Byron C and Chaves, Paulo H and Couper, David and Jacobs, David R and Lloyd-Jones, Donald and Kalhan, Ravi and Newman, Anne B and O{\textquoteright}Connor, George T and Umans, Jason G and White, Wendy B and Yende, Sachin and Oelsner, Elizabeth C} }