|
|
Bhatta, L., Leivseth, L., Mai, X. - M., Chen, Y., Henriksen, A. H., Langhammer, A., et al. (2018). Prevalence and trend of COPD from 1995-1997 to 2006-2008: The HUNT study, Norway. Respir Med, 138, 50–56.
Abstract: BACKGROUND: COPD is a major cause of morbidity and mortality across the world and new estimates of prevalence and trend are of great importance. We aimed to estimate the prevalence and trend of COPD from 1995-1997 to 2006-2008 in Norwegian adults >/=40 years from the Nord-Trondelag Health Study. MATERIAL AND METHODS: COPD was assessed using a fixed-ratio and lower limit of normal (LLN) criteria. Pre-bronchodilator spirometry was performed during 1995-1997 (n=7158) and 2006-2008 (n=8788). The prevalence of COPD was weighted using the inverse probability of selection and predicted probability of response. RESULTS: The prevalence of pre-bronchodilator COPD was 16.7% in 1995-1997 and 14.8% in 2006-2008 using fixed-ratio criteria, and 10.4% in 1995-1997 and 7.3% in 2006-2008 using LLN criteria. The prevalence of LLN COPD was higher among men (13.0% in 1995-1997, 7.7% in 2006-2008) than women (8.0% in 1995-1997, 6.9% in 2006-2008). From 1995-1997 to 2006-2008, the prevalence decreased among men but remained relatively stable among women. Over the 11-year period, the cumulative incidence of pre-bronchodilator COPD using LLN criteria was 3.3% and 2.7% among men and women respectively. The prevalence of self-reported asthma and respiratory symptoms increased. CONCLUSIONS: The prevalence declined in men but not in women from 1995-1997 to 2006-2008, and was consistently higher among men than women.
|
|
|
|
Quanjer, P. H., Ruppel, G. L., Langhammer, A., Krishna, A., Mertens, F., Johannessen, A., et al. (2017). Bronchodilator Response in FVC Is Larger and More Relevant Than in FEV1 in Severe Airflow Obstruction. Chest, 151(5), 1088–1098.
Abstract: BACKGROUND: Recommendations on interpreting tests of bronchodilator responsiveness (BDR) are conflicting. We investigated the dependence of BDR criteria on sex, age, height, ethnicity, and severity of respiratory impairment. METHODS: BDR test data were available from clinical patients in the Netherlands, New Zealand, and the United States (n = 15,278; female subjects, 51.7%) and from surveys in Canada, Norway, and five Latin-American countries (n = 16,250; female subjects, 54.7%). BDR calculated according to FEV1, FVC, and FEV1/FVC was expressed as absolute change, a percentage of the baseline level (% baseline), a percentage of the predicted value (% predicted), and z score. RESULTS: Change (Delta) in FEV1 and FVC, in milliliters, was unrelated to the baseline value but was biased toward age, height, sex, and level of airways obstruction; DeltaFEV1 was significantly lower in African Americans. In 1,106 subjects with low FEV1 (200-1,621 mL) the FEV1 increased by 12% to 44.7% relative to baseline but < 200 mL. Expressing BDR as a percentage of the predicted value or as a z score attenuated the bias and made the 200-mL criterion redundant, but reduced positive responses by half. DeltaFEV1 % baseline increased with the level of airflow obstruction but decreased with severe obstruction when expressed as z scores or % predicted; DeltaFVC, however expressed, increased with the level of airflow obstruction. CONCLUSIONS: Expressing FEV1 responsiveness as % baseline spuriously suggests that responsiveness increases with the severity of respiratory impairment. Expressing change in FEV1 or FVC as % predicted or as z scores eliminates this artifact and renders the required 200-mL minimum increase redundant. In severe airways obstruction DeltaFVC should be critically evaluated as an index of clinically important relief of hyperinflation, with implications for bronchodilator drug trials.
|
|
