Spirometric Reference Equations for Elderly Chinese in Jinan Aged 60–84 Years

Abstract

Background:The interpretation of spirometry varies on different reference values. Older people are usually underrepresented in published predictive values. This study aimed at developing spirometric reference equations for elderly Chinese in Jinan aged 60–84 years and to compare them to previous equations.Methods:The project covered all of Jinan city, and the recruitment period lasted 9 months from January 1, 2017 to September 30, 2017, 434 healthy people aged 60–84 years who had never smoked (226 females and 208 males) were recruited to undergo spirometry. Vital capacity (VC), forced VC (FVC), forced expiratory volume in 1 s (FEV1), FEV1/FVC, FEV1/VC, FEV6, peak expiratory flow, and forced expiratory flow at 25%, 50%, 75%, and 25–75% of FVC exhaled (FEF25%, FEF50%, FEF75%, and FEF25–75%) were analyzed. Reference equations for mean and the lower limit of normal (LLN) were derived using the lambda-mu-sigma method. Comparisons between new and previous equations were performed by paired t-test.Results:New reference equations were developed from the sample. The LLN of FEV1/FVC, FEF25–75% computed using the 2012-Global Lung Function Initiative (GLI) and 2006-Hong Kong equations were both lower than the new equations. The biggest degree of difference for FEV1/FVC was 19% (70.46% vs. 59.29%, t = 33.954, P < 0.01) and for maximal midexpiratory flow (MMEF, equals to FEF25–75%) was 22% (0.82 vs. 0.67, t = 21.303, P < 0.01). The 1990-North China and 2009-North China equations predicted higher mean values of FEV1/FVC and FEF25–75% than the present model. The biggest degrees of difference were −4% (78.31% vs. 81.27%, t = −85.359, P < 0.01) and −60% (2.11 vs. 4.68, t = −170.287, P < 0.01), respectively.Conclusions:The newly developed spirometric reference equations are applicable to elderly Chinese in Jinan. The 2012-GLI and 2006-Hong Kong equations may lead to missed diagnoses of obstructive ventilatory defects and the small airway dysfunction, while traditional linear equations for all ages may lead to overdiagnosis.

Standardization of Spirometry 2019 Update. An Official American Thoracic Society and European Respiratory Society Technical Statement

“…Recording FEV 6 has the advantages of being more reproducible than FVC, being less physically demanding for patients, reducing the risk of syncope, and providing a more explicit EOFE ( 104 – 107 ). Appropriate reference values for FEV 6 must be used ( 108 – 111 ). The ratio of FEF at 50% VC to forced inspiratory flow at 50% VC (FEF 50 /FIF 50 ) is sometimes used as an indicator of upper airway obstruction ( 112 , 113 ).…”

<p>Impacts of Different Spirometry Reference Equations and Diagnostic Criteria on the Frequency of Airway Obstruction in Adult People of North China</p>

“…In our previous study, we proved that the LLN of FEV1/FVC of GLI-2012 was lower than normal people aged 60-84 years old in Jinan, a city with more than 7 million people in North China. 32 So both Zhongshan-2011 and GLI-2011 may not be the most appropriate reference equations for the adult people of North China.…”

Reference Values and Related Factors for Peak Expiratory Flow in Middle-aged and Elderly Chinese

“…Previous to our study, PEF reference values for Chinese were estimated. However, several disadvantages limited the national wide usage, for example, based on children and adolescence, or small local regions, or small samples [15,16,[28][29][30][31]. Jian estimated the reference value for 7,115 healthy Han nationality people aged 4~80 years old.…”

“…Most previous studies in China have focused on children and adolescents [14,15] with few reports on adults [10,16], especially for the middle-aged and older. Although one study [10] included 7115 subjects aged 4-80 years in China, the middle-aged and older people accounted for only a small proportion and relevant variables were not included.…”

“…Although one study [10] included 7115 subjects aged 4-80 years in China, the middle-aged and older people accounted for only a small proportion and relevant variables were not included. Another study based on elderly was conducted in Jinan [16], a city of eastern China, which means that it could not represent the elderly population of the whole of China.…”