Analysis of high predicted pulmonary function: possibility of overestimation in small elderly examinees

• Main Authors: Youjin Chang, Ho Cheol Kim, Kyung-Wook Jo, Jae Seung Lee, Yeon-Mok Oh, Sang Do Lee, Sei Won Lee
• Format: Article
• Language: English
• Published: The Korean Association of Internal Medicine 2020-01-01
• Series: The Korean Journal of Internal Medicine
• Subjects: pulmonary function test; spirometry; forced expiratory volume; forced vital capacity
• Online Access: http://www.kjim.org/upload/pdf/kjim-2018-305.pdf

Background/Aims Few studies have attempted to interpret unusually high predicted pulmonary function test results. This study aimed to investigate the demographic features of patients with an unusually high predicted pulmonary function. Methods The demographic data of subjects who underwent pulmonary function testing at a tertiary referral hospital during between January 2011 and December 2011 were retrospectively reviewed. Results Of the 68,693 included patients, 55 (0.08%) had a percent predicted forced expiratory volume in 1 second or forced vital capacity ≥ 140%. These patients had a relatively older median age (72 years vs. 54 years, p < 0.001), female predominance (65.5% vs. 42.5%, p = 0.001), lower body weight (52.5 kg vs. 64.5 kg, p < 0.001) and shorter height (148.4 cm vs. 164.2 cm, p < 0.001). Furthermore, 6.1% of women older than 80 years with weight < 50 kg and height < 150 cm had a high predicted pulmonary function. Conclusions A high predicted pulmonary function is not rare among elderly subjects with a small body size. Physicians should consider the demographics of the examinees, especially those of minority populations, particularly as the test results might be determined using an incorrect reference equation.