Dataset Information

Comparison of the fixed ratio and the Z-score of FEV1/FVC in the elderly population: a long-term mortality analysis from the Third National Health and Nutritional Examination Survey.

ABSTRACT: Despite the ongoing intense debate on the definition of airflow limitation by spirometry in the elderly population, there have only been few studies comparing the fixed ratio and the Z-score of forced expiratory volume in 1 second (FEV1)/forced vital capacity (FVC) in terms of long-term mortalities. In this study, we aimed to identify the proper method for accurately defining the airflow limitation in terms of long-term mortality prediction in the elderly population.Data were collected from the Third National Health and Nutrition Examination Survey in the US. Non-Hispanic Caucasians aged 65-80 years were included. The receiver operating characteristic (ROC) curves of both methods were plotted and compared for 10-year all-cause, respiratory, and COPD mortalities.Of 1,331 subjects, the mean age was 71.7 years and 805 (60.5%) were males. For the 10-year all-cause mortality, the area under the curve (AUC) of the fixed ratio was significantly greater than that of the Z-score of FEV1/FVC, but both showed poor prediction performance (0.633 vs 0.616, p<0.001). For the 10-year respiratory and COPD mortalities, both the fixed ratio and the Z-score of FEV1/FVC showed comparable prediction performance with greater AUCs (0.784 vs 0.778, p=0.160, and 0.896 vs 0.896, p=0.971, respectively). Interestingly, the conventional cutoff of 0.7 in the fixed ratio was consistently higher than the optimal for the 10-year all-cause, respiratory, and COPD mortalities (0.70 vs 0.69, 0.62, and 0.61, respectively), whereas that of -1.64 in the Z-score of FEV1/FVC was consistently lower than the optimal cutoff (-1.64 vs -1.31, -1.47, and -1.41, respectively).In the elderly population, both the fixed ratio and the Z-score of FEV1/FVC showed comparable prediction performance for the 10-year respiratory and COPD mortalities. However, the conventional cutoff of neither 0.70 in the fixed ratio nor -1.64 in the Z-score of FEV1/FVC was optimal for predicting the long-term mortalities.

SUBMITTER: Oh DK

PROVIDER: S-EPMC5857155 | biostudies-literature | 2018

REPOSITORIES: biostudies-literature

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Comparison of the fixed ratio and the <i>Z</i>-score of FEV<sub>1</sub>/FVC in the elderly population: a long-term mortality analysis from the Third National Health and Nutritional Examination Survey.

Oh Dong Kyu DK Baek Seunghee S Lee Sei Won SW Lee Jae Seung JS Lee Sang-Do SD Oh Yeon-Mok YM

International journal of chronic obstructive pulmonary disease 20180314

<h4>Background and objective</h4>Despite the ongoing intense debate on the definition of airflow limitation by spirometry in the elderly population, there have only been few studies comparing the fixed ratio and the <i>Z</i>-score of forced expiratory volume in 1 second (FEV<sub>1</sub>)/forced vital capacity (FVC) in terms of long-term mortalities. In this study, we aimed to identify the proper method for accurately defining the airflow limitation in terms of long-term mortality prediction in t ...[more]

PMID: 29559774

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Project description:BACKGROUND:Adipose tissue produces leptin, which is pro-inflammatory, and adiponectin, which has anti-inflammatory properties. Participants with chronic spinal cord injury (SCI) have increased body fat and are at increased risk for respiratory illness. OBJECTIVE:To assess the associations between leptin and adiponectin with pulmonary function in a chronic SCI cohort. DESIGN:Cross-sectional study. SETTING:Veterans Affairs Medical Center. PARTICIPANTS:A total of 285 participants (237 men and 48 women) with chronic SCI with mean (standard deviation) injury duration 17.8 (13.2) years from the VA Boston and the community participating in an epidemiologic study assessing factors associated with respiratory health. METHODS:Participants (24.6% cervical American Spinal Injury Association Impairment Scale (AIS) level A, B, and C; 33.6% other AIS A, B, and C; 41.8% AIS D) provided a blood sample, completed a respiratory health questionnaire, and underwent spirometry. Linear regression methods were used to assess cross-sectional associations between plasma leptin and adiponectin with spirometric measures of pulmonary function adjusted for age, race, gender, and height. Level and severity of SCI, mobility mode, body mass index, smoking, chronic obstructive pulmonary disease, asthma, chest injury history, laboratory batch, and other potential confounders were also considered. MAIN OUTCOME MEASUREMENTS:forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), and FEV1/FVC. RESULTS:There was a statistically significant inverse relationship between plasma leptin assessed in quartiles or as a continuous covariate with FEV1 and FVC. In fully adjusted models, each interquartile range (16,214 pg/mL) increase in leptin was associated with a significant decrease in FEV1 (-93.1 mL; 95% confidence interval = -166.2, -20.0) and decrease in FVC (-130.7 mL; 95% confidence interval = -219.4, -42.0). There were no significant associations between leptin and FEV1/FVC or between plasma adiponectin with FEV1, FVC, or FEV1/FVC. CONCLUSION:Plasma leptin in individuals with chronic SCI is inversely associated with FEV1 and FVC, independently of SCI level and severity and other covariates. This finding suggests that plasma leptin may contribute to reduced pulmonary function in chronic SCI. LEVEL OF EVIDENCE:II.

Project description:ImportanceAccording 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.ObjectiveTo determine the discriminative accuracy of various FEV1:FVC fixed thresholds for predicting COPD-related hospitalization and mortality.Design, setting, and participantsThe 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.ExposuresPresence 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 measuresThe 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.ResultsAmong 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 relevanceDefining 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.

Dataset Information

Comparison of the fixed ratio and the Z-score of FEV1/FVC in the elderly population: a long-term mortality analysis from the Third National Health and Nutritional Examination Survey.

Publications

Comparison of the fixed ratio and the <i>Z</i>-score of FEV<sub>1</sub>/FVC in the elderly population: a long-term mortality analysis from the Third National Health and Nutritional Examination Survey.

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