BACKGROUND: Oxygen desaturation during walking can have important consequence on prognosis of COPD patients. However, a standard 6-min walk test (6MWT), useful in detecting desaturation in COPD patients, can be difficult to execute in some settings of COPD management, as in the community healthcare service. We evaluated a new scoring system for the risk of oxygen desaturation during walking in COPD patients: the walking desaturation score. METHODS: We collected data from symptomatic COPD in-patients admitted for rehabilitation (derivation cohort) and out-patients referred to the local community health service (validation cohort). SpO2 was monitored during 6MWT, and the subjects were classified as walking desaturators or non-desaturators. By a regression analysis model we assigned a weighted score proportional to the measured percentage of explained variance for each variable. Risk estimates were computed as odds ratios. A receiver operating characteristic curve analysis and a Hosmer-Lemeshow goodness-of-fit test were then performed to measure discrimination and calibration of walking desaturation score. RESULTS: Baseline characteristics in the derivation cohort (n= 435, 74% of whom were walking desaturators) and the validation cohort (n =238, 37% of whom were walking desaturators) were different. Resting arterial oxygen saturation measured from an arterial blood sample, PaO2, and percent-of-predicted FEV1 were the variables that predicted walking desaturation. The proportion of walking desaturators (and odds ratio estimate) gradually increased according to walking desaturation score (range 0-6) and associated categories of desaturation risk (total walking desaturation score: low 0 or 1, high 2-3, very high 4-6) (chi-square P <.001). There was considerable predictive discrimination (area under the curve 0.90, 95% CI 0.86-0.93, P <.001), and calibration (Hosmer-Lemeshow chi-square 1.31, P =.86) values have been shown. CONCLUSIONS: Walking desaturation score accurately predicts and classifies the risk of walking desaturation in COPD patients. ClinicalTrials.gov Number NCT01303913. © 2013 Daedalus Enterprises.

Predicting walking-induced oxygen desaturations in COPD patients: A statistical model

CRISAFULLI, Ernesto;
2013-01-01

Abstract

BACKGROUND: Oxygen desaturation during walking can have important consequence on prognosis of COPD patients. However, a standard 6-min walk test (6MWT), useful in detecting desaturation in COPD patients, can be difficult to execute in some settings of COPD management, as in the community healthcare service. We evaluated a new scoring system for the risk of oxygen desaturation during walking in COPD patients: the walking desaturation score. METHODS: We collected data from symptomatic COPD in-patients admitted for rehabilitation (derivation cohort) and out-patients referred to the local community health service (validation cohort). SpO2 was monitored during 6MWT, and the subjects were classified as walking desaturators or non-desaturators. By a regression analysis model we assigned a weighted score proportional to the measured percentage of explained variance for each variable. Risk estimates were computed as odds ratios. A receiver operating characteristic curve analysis and a Hosmer-Lemeshow goodness-of-fit test were then performed to measure discrimination and calibration of walking desaturation score. RESULTS: Baseline characteristics in the derivation cohort (n= 435, 74% of whom were walking desaturators) and the validation cohort (n =238, 37% of whom were walking desaturators) were different. Resting arterial oxygen saturation measured from an arterial blood sample, PaO2, and percent-of-predicted FEV1 were the variables that predicted walking desaturation. The proportion of walking desaturators (and odds ratio estimate) gradually increased according to walking desaturation score (range 0-6) and associated categories of desaturation risk (total walking desaturation score: low 0 or 1, high 2-3, very high 4-6) (chi-square P <.001). There was considerable predictive discrimination (area under the curve 0.90, 95% CI 0.86-0.93, P <.001), and calibration (Hosmer-Lemeshow chi-square 1.31, P =.86) values have been shown. CONCLUSIONS: Walking desaturation score accurately predicts and classifies the risk of walking desaturation in COPD patients. ClinicalTrials.gov Number NCT01303913. © 2013 Daedalus Enterprises.
6-min walk test
Community healthcare
COPD
Decision making
Oxygen desaturation
Risk score
Aged
Aged
80 and over
Exercise Test
Female
Humans
Male
Middle Aged
Oximetry
Oxygen
Prognosis
Prospective Studies
Pulmonary Disease
Chronic Obstructive
ROC Curve
Regression Analysis
Risk Assessment
Spirometry
Walking
Models
Statistical
Pulmonary and Respiratory Medicine
Critical Care and Intensive Care Medicine
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11562/1030113
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 13
  • ???jsp.display-item.citation.isi??? 10
social impact