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

Ernesto Crisafulli, Andrea Iattoni, Elena Venturelli, Gherardo Siscaro, Claudio Beneventi, Alfredo Cesario, Enrico M. Clini

Research output: Contribution to journalArticlepeer-review


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

Original languageEnglish
Pages (from-to)1495-1503
Number of pages9
JournalRespiratory Care
Issue number9
Publication statusPublished - Sep 1 2013


  • 6-min walk test
  • Community healthcare
  • COPD
  • Decision making
  • Oxygen desaturation
  • Risk score

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine
  • Critical Care and Intensive Care Medicine


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