Exertional Desaturation as a Predictor of Rapid Lung Function Decline in COPD

Abstract

Background: To date, no clinical parameter has been associated with the decline in lung function other than emphysema severity in COPD. Objectives: The main purpose of this study was to explore whether the rate of lung function decline differs between COPD patients with and without exertional desaturation. Methods: A total of 224 subjects were selected from the Korean Obstructive Lung Disease cohort. Exertional desaturation was assessed using the 6-min walk test (6MWT), and defined as a post-exercise oxygen saturation (Sp<smlcap>O</smlcap>₂) of <90% or a ≥4% decrease. The cohort was divided into desaturator (n = 47) and non-desaturator (n = 177) groups. Results: There was a significant difference between the desaturator and non-desaturator groups in terms of the change in pre-bronchodilator forced expiratory volume in 1 s (FEV₁) over a 3-year period of follow-up (p = 0.006). The mean rate of decline in FEV₁ was greater in the desaturator group (33.8 ml/year) than in the non-desaturator group (11.6 ml/year). A statistically significant difference was also observed between the two groups in terms of the change in the St. George's Respiratory Questionnaire (SGRQ) total score over 3 years (p = 0.001). Conclusions: This study suggests, for the first time, that exertional desaturation may be a predictor of rapid decline in lung function in patients with COPD. The 6MWT may be a useful test to predict a rapid lung function decline in COPD.

Determinants of exercise-induced oxygen desaturation including pulmonary emphysema in COPD: Results from the ECLIPSE study

“…[3][4][5] Yet, their physiological determinants and clinical consequences are still subject of debate. In general, patients with EID are characterized by severe airflow limitation, low diffusing carbon monoxide capacity (DLCO), reduced resting arterial oxygenation [6][7][8][9] and the presence of emphysema [10][11][12] In addition, EID is also related to numerous variables that include the rate of lung function decline and health status 13 , physical activity 14 , and the outcomes of hospitalization as well as mortality. 15,16 The determinants of EID, however, have not been validated in a large cohort of COPD patients followed up prospectively.…”

Vitamin D Deficiency Is Associated with Rapid Decline in Exercise Capacity in Male Patients with Chronic Obstructive Pulmonary Disease

“…The mean lung density was calculated automatically during expiration and inspiration [20]. The air-trapping index was estimated by calculating the ratio of the mean lung density at expiration and inspiration [20].…”

“…Airway dimensions [wall area (WA), lumen area (LA) and wall area percent (WA%)] were measured in each bronchus. WA% was defined as WA/(WA+LA) × 100 and termed the airway index [20]. …”

Exertional Desaturation as a Predictor of Rapid Lung Function Decline in COPD: Consider Pulmonary Embolic Disease and Pulmonary Hypertension Too

“…Kim et al [1] report the potential predictive value of exertional desaturation in chronic obstructive pulmonary disease (COPD) patients for decline in lung function. There was no noted difference in exacerbations to account for the decline in lung function.…”