Risk stratification by the lower limit of normal of FEV1/FVC for postoperative outcomes in patients with COPD undergoing thoracic surgery.
BACKGROUND
Mounting evidence suggests that airway obstruction defined by the lower limit of normal (LLN) of forced expiration volume in 1s (FEV1)/forced vital capacity (FVC) might be an important predictor of mortality in patients with an FEV1/FVC ratio below 0.70. Although better risk stratification for postoperative outcomes in patients with chronic obstructive pulmonary disease (COPD) undergoing thoracic surgery is warranted, whether an FEV1/FVC ratio below 0.70 but above the LLN (i.e., in-between) could identify patients at risk for adverse postoperative outcomes has not been fully evaluated.


METHODS
To determine the clinical impact of this "in-between" group of patients with COPD, we evaluated whether classification of the in-between group and the COPD group with FEV1/FVC ratios below 0.70 and below the LLN could provide more accurate risk stratification for postoperative outcomes in COPD patients undergoing thoracic surgery.


RESULTS
The criterion of LLN classified 302 patients with an FEV1/FVC ratio below 0.70 into either the in-between group (124 cases) or the COPD group (178 cases). The COPD group showed a 3-fold increase in prolonged oxygen therapy (POT) and a 50% increase in prolonged postoperative stay (PPS), as compared with the in-between group, with an adjusted odds ratio of 3.068 (95% confidence interval: 1.806-5.213) for POT.


CONCLUSIONS
Based on the finding that the in-between group could independently identify patients at risk for adverse postoperative outcomes, LLN assessment of the FEV1/FVC ratio might provide more accurate risk stratification in COPD patients undergoing thoracic surgery.
['Osuka|Satoko|S|', 'Hashimoto|Naozumi|N|', 'Sakamoto|Koji|K|', 'Wakai|Kenji|K|', 'Yokoi|Kohei|K|', 'Hasegawa|Yoshinori|Y|']
D000328:Adult D000368:Aged D000369:Aged, 80 and over D005260:Female D005541:Forced Expiratory Volume D006801:Humans D006931:Hyperbaric Oxygenation D007902:Length of Stay D008297:Male D008875:Middle Aged D011183:Postoperative Complications D011184:Postoperative Period D029424:Pulmonary Disease, Chronic Obstructive D012306:Risk D018570:Risk Assessment D019616:Thoracic Surgical Procedures D016896:Treatment Outcome D014797:Vital Capacity
Risk stratification Lower limit of normal Thoracic surgery 0.70 fixed ratio Chronic obstructive lung disease