Application of a new spirometric reference equation and its impact on the staging of Korean chronic obstructive pulmonary disease patients.
OBJECTIVE
A new spirometric reference equation was recently developed from the first national chronic obstructive pulmonary disease (COPD) survey in Korea. However, Morris' equation has been preferred for evaluating spirometric values instead. The objective of this study was to evaluate changes in severity staging in Korean COPD patients by adopting the newly developed Korean equation.


METHODS
We evaluated the spirometric data of 441 COPD patients. The presence of airflow limitation was defined as an observed post-bronchodilator forced expiratory volume in one second/forced vital capacity (FEV1/FVC) less than 0.7, and the severity of airflow limitation was assessed according to GOLD stages. Spirometric values were reassessed using the new Korean equation, Morris' equation and other reference equations.


RESULTS
The severity of airflow limitation was differently graded in 143 (32.4%) patients after application of the new Korean equation when compared with Morris' equation. All 143 patients were reallocated into more severe stages (49 at mild stage, 65 at moderate stage, and 29 at severe stage were changed to moderate, severe and very severe stages, respectively). Stages according to other reference equations were changed in 18.6-49.4% of the patients.


CONCLUSIONS
These results indicate that equations from different ethnic groups do not sufficiently reflect the airflow limitation of Korean COPD patients. The Korean reference equation should be used for Korean COPD patients in order to administer proper treatment.
Division of Pulmonology, Allergy and Critical Care Medicine, Department of Internal Medicine, Hallym University Medical Center, 896 Pyeongchon-dong, Dongan-gu, Anyang 431-070, Korea.
Yong Il
YI
Hwang
Eun Ji
EJ
Kim
Chang Youl
CY
Lee
Sunghoon
S
Park
Jeong Hee
JH
Choi
Yong Bum
YB
Park
Seung Hun
SH
Jang
Cheol Hong
CH
Kim
Tae Rim
TR
Shin
Sang Myeon
SM
Park
Dong-Gyu
DG
Kim
Myung-Goo
MG
Lee
In-Gyu
IG
Hyun
Ki-Suck
KS
Jung
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People; D005260:Female; D006801:Humans; D007723:Korea; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis* / Q000473:pathology; D012189:Retrospective Studies; D013147:Spirometry / Q000379:methods*