In:
Respiration, S. Karger AG, Vol. 84, No. 5 ( 2012), p. 353-359
Abstract:
〈 b 〉 〈 i 〉 Background: 〈 /i 〉 〈 /b 〉 Previous studies with small sample sizes reported contradicting findings as to whether pulmonary function tests can predict exercise-induced oxygen desaturation (EID). 〈 b 〉 〈 i 〉 Objective: 〈 /i 〉 〈 /b 〉 To evaluate whether forced expiratory volume in one second (FEV 〈 sub 〉 1 〈 /sub 〉 ), resting oxygen saturation (Sp 〈 smlcap 〉 o 〈 /smlcap 〉 〈 sub 〉 2 〈 /sub 〉 ) and diffusion capacity for carbon monoxide (D 〈 smlcap 〉 l 〈 /smlcap 〉 〈 smlcap 〉 c 〈 /smlcap 〉 〈 smlcap 〉 o 〈 /smlcap 〉 ) are predictors of EID in chronic obstructive pulmonary disease (COPD). 〈 b 〉 〈 i 〉 Methods: 〈 /i 〉 〈 /b 〉 We measured FEV 〈 sub 〉 1 〈 /sub 〉 , D 〈 smlcap 〉 l 〈 /smlcap 〉 〈 smlcap 〉 c 〈 /smlcap 〉 〈 smlcap 〉 o 〈 /smlcap 〉 , Sp 〈 smlcap 〉 o 〈 /smlcap 〉 〈 sub 〉 2 〈 /sub 〉 at rest and during a 6-min walking test as well as physical activity by an accelerometer. A drop in Sp 〈 smlcap 〉 o 〈 /smlcap 〉 〈 sub 〉 2 〈 /sub 〉 of 〉 4 to 〈 90% was defined as EID. To evaluate associations between measures of lung function and EID univariate and multivariate analyses were used and positive/negative predictive values were calculated. Receiver operating characteristic curve analysis was performed to determine the most useful threshold in order to predict/exclude EID. 〈 b 〉 〈 i 〉 Results: 〈 /i 〉 〈 /b 〉 We included 154 patients with COPD (87 females). The mean FEV 〈 sub 〉 1 〈 /sub 〉 was 43.0% (19.2) predicted and the prevalence of EID was 61.7%. The only independent predictor of EID was FEV 〈 sub 〉 1 〈 /sub 〉 and the optimal cutoff value of FEV 〈 sub 〉 1 〈 /sub 〉 was at 50% predicted (area under ROC curve, 0.85; p 〈 0.001). The positive predictive value of a threshold of FEV 〈 sub 〉 1 〈 /sub 〉 〈 50% was 0.83 with a likelihood ratio of 3.03 and the negative predicting value of a threshold of FEV 〈 sub 〉 1 〈 /sub 〉 ≥80% was 1.0. The severity of EID was correlated with daily physical activity (r = –0.31, p = 0.008). 〈 b 〉 〈 i 〉 Conclusions: 〈 /i 〉 〈 /b 〉 EID is highly prevalent among patients with COPD and can be predicted by FEV 〈 sub 〉 1 〈 /sub 〉 . EID seems to be associated with impaired daily physical activity which supports its clinical importance.
Type of Medium:
Online Resource
ISSN:
0025-7931
,
1423-0356
Language:
English
Publisher:
S. Karger AG
Publication Date:
2012
detail.hit.zdb_id:
1464419-8
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