Respiratory Symptoms, Spirometric Respiratory Impairment, and Respiratory Disease in Middle‐Aged and Older Persons

Abstract

Objectives To evaluate whether a novel definition of spirometric respiratory impairment (Global Lung Initiative [GLI]) is strongly associated with respiratory symptoms and, in turn, frequently establishes symptomatic respiratory disease. Design Cross-sectional. Setting Third National Health and Nutrition Examination Survey. Participants Community-dwelling, ages 40-80 (N=7,115). Measurements GLI-defined spirometric respiratory impairment (airflow-obstruction and restrictive-pattern), dyspnea on exertion (DOE), chronic bronchitis (CB), and wheezing. Results Among participants aged 40-80, prevalence rates were 12.7% and 6.2% for airflow-obstruction and restrictive-pattern and 28.6%, 12.6%, and 12.9% for DOE, CB, and wheezing, respectively. Relative to normal spirometry, airflow-obstruction was associated with DOE, CB, and wheezing—adjusted odds ratios (adjORs): 1.69 (1.42, 2.02), 1.92 (1.62, 2.29), and 2.50 (2.08, 3.00), respectively. Similarly, restrictive-pattern was associated with DOE, CB, and wheezing—adjORs: 1.75 (1.36, 2.25), 1.39 (1.08, 1.78) and 1.53 (1.15, 2.04), respectively. Among participants who had airflow-obstruction and restrictive-pattern, however, only a minority had DOE (38.6% and 45.5%), CB (23.3% and 15.9%), and wheezing (24.4% and 19.1%), respectively, yielding a positive predictive value (PPV) of 53% for any respiratory symptom in the setting of any spirometric respiratory impairment. In addition, most participants who had DOE, CB, and wheezing did not have airflow-obstruction or restrictive-pattern (73.0%, 67.8%, and 66.8%, respectively), yielding a PPV of 26% for any spirometric respiratory impairment in the setting of any respiratory symptom. The results differed only modestly when stratified by the age groups of 40-64 and 65-80. Conclusion GLI-defined spirometric respiratory impairment increased the likelihood of respiratory symptoms relative to normal spirometry, but was nonetheless a poor predictor of respiratory symptoms. Similarly, respiratory symptoms were poor predictors of GLI-defined spirometric respiratory impairment. Hence, a comprehensive assessment is needed when evaluating respiratory symptoms, even in the presence of a spirometric respiratory impairment.

Phenotype of Normal Spirometry in an Aging Population

“…Importantly, despite having moderate COPD by GOLD, participants who otherwise had normal spirometry by GLI had adjusted mean values and 95% CIs in the normal range for dyspnea grade, SGRQ, 6MWD, BD reversibility, % emphysema, % gas trapping, and Pi10-SRWA (Table 3). These results suggest that GOLD misclassifies a normal phenotype as respiratory impairment in older persons, a consequence of the previously described age-related limitations regarding use of a fixed ratio for FEV 1 /FVC, and of % predicted for FEV 1 and FVC (2, 8-15).…”

“…BD reversibility was considered present if the post-BD FEV 1 showed an increase of greater than 12% (5).…”

“…The spirometric measures included pre-BD values for FEV 1 and FVC, with FEV 1 /FVC calculated from the largest FEV 1 and FVC values that were recorded in any of the accepted spirometric maneuvers (5,32). The use of pre-BD values may be questioned but offers at least three advantages over the current standard of using post-BD values.…”

“…Using GOLD criteria (3) and pre-BD values, the % predicted values for FEV 1 and FVC were calculated as (measured O predicted) 3 100, with predicted values derived from regression equations (38). Participants were classified as having normal spirometry by FEV 1 /FVC greater than or equal to 0.70 and FVC greater than or equal to 80% predicted, as restrictive pattern by FEV 1 /FVC greater than or equal to 0.70 and FVC less than 80% predicted, and as COPD (airflow obstruction) by FEV 1 /FVC less than 0.70.…”

“…The GOLD approach is structured and has provided many benefits and insights, but it also has limitations, especially in aging populations (2,(8)(9)(10)(11)(12)(13)(14)(15). Specifically, because aging impacts respiratory mechanics, the fixed GOLD threshold of less than 0.70 for the ratio FEV 1 to FVC frequently misclassifies normal-for-age spirometry as airflow obstruction. Such misclassification can occur in otherwise asymptomatic never-smokers, starting at about age 45-50 (2,(8)(9)(10)(11)(12)(13)(14)(15).…”