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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.
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Skaug, E. - A., Aspenes, S. T., Oldervoll, L., Morkedal, B., Vatten, L., Wisloff, U., et al. (2013). Age and gender differences of endothelial function in 4739 healthy adults: the HUNT3 Fitness Study. Eur J Prev Cardiol, 20(4), 531–540.
Abstract: AIMS: Endothelial dysfunction is an important marker for prognosis in patients with coronary heart disease. However, there are no reference values for endothelial function in a healthy population. Our aim was to determine the distribution of flow-mediated dilation (FMD) values by gender and age in healthy adults. METHODS: FMD was measured by ultrasound during reactive hyperaemia in the brachial artery of 4739 adults aged 20-89 years, who were free from self-reported cardiovascular or pulmonary disease. Differences in FMD across age and gender were analysed by multiple linear regression. RESULTS: Total mean +/- SD FMD was 4.8 +/- 4.2%, with corresponding estimates of 4.3 +/- 3.9% for men and 5.3 +/- 4.5% for women (p < 0.001). In total, 17% had FMD </=0%, indicating endothelial dysfunction. FMD decreased with increasing age in both genders up to 70 years for men and 80 for women (p < 0.001). In women, age-related decline in FMD was steepest after age 45; in men, a steady decline after age 30. In men 80 years and older, FMD was higher than in men aged 50-79 years. CONCLUSIONS: The distribution of FMD in this study is representative of the respective age and gender groups of a healthy population and may be a useful reference for future studies. The high proportion of endothelial dysfunction came as a surprise. Its age and gender distribution suggest that FMD </=0% precedes cardiovascular disease and that it may be a powerful non-invasive biomarker for identifying high-risk individuals.
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