title: Risk prediction score for severe high altitude illness: a cohort study.
abstract: BACKGROUND
  Risk prediction of acute mountain sickness, high altitude (HA) pulmonary or cerebral edema is currently based on clinical assessment. Our objective was to develop a risk prediction score of Severe High Altitude Illness (SHAI) combining clinical and physiological factors. Study population was 1017 sea-level subjects who performed a hypoxia exercise test before a stay at HA. The outcome was the occurrence of SHAI during HA exposure. Two scores were built, according to the presence (PRE, n = 537) or absence (ABS, n = 480) of previous experience at HA, using multivariate logistic regression. Calibration was evaluated by Hosmer-Lemeshow chisquare test and discrimination by Area Under ROC Curve (AUC) and Net Reclassification Index (NRI).
  
  
  RESULTS
  The score was a linear combination of history of SHAI, ventilatory and cardiac response to hypoxia at exercise, speed of ascent, desaturation during hypoxic exercise, history of migraine, geographical location, female sex, age under 46 and regular physical activity. In the PRE/ABS groups, the score ranged from 0 to 12/10, a cut-off of 5/5.5 gave a sensitivity of 87%/87% and a specificity of 82%/73%. Adding physiological variables via the hypoxic exercise test improved the discrimination ability of the models: AUC increased by 7% to 0.91 (95%CI: 0.87-0.93) and 17% to 0.89 (95%CI: 0.85-0.91), NRI was 30% and 54% in the PRE and ABS groups respectively. A score computed with ten clinical, environmental and physiological factors accurately predicted the risk of SHAI in a large cohort of sea-level residents visiting HA regions.
authors: Université Paris Est, Faculté de Médecine, EA 4393, Laboratoire d'Investigation Clinique, Créteil, France; AP-HP, Groupe Henri Mondor-Albert Chenevier, Service de Santé Publique, Créteil, France.
authors: Florence
authors: F
authors: Canouï-Poitrine
authors: Université Paris Est, Faculté de Médecine, EA 4393, Laboratoire d'Investigation Clinique, Créteil, France; AP-HP, Groupe Henri Mondor-Albert Chenevier, Service de Santé Publique, Créteil, France.
authors: Kalaivani
authors: K
authors: Veerabudun
authors: AP-HP, Hôpital Avicenne, Service d'Anesthésie et Réanimation, Bobigny, France.
authors: Philippe
authors: P
authors: Larmignat
authors: AP-HP, Hôpital Avicenne, Service de Physiologie, Explorations Fonctionnelles et Médecine du Sport, Bobigny, France.
authors: Murielle
authors: M
authors: Letournel
authors: Université Paris Est, Faculté de Médecine, EA 4393, Laboratoire d'Investigation Clinique, Créteil, France; AP-HP, Groupe Henri Mondor-Albert Chenevier, Service de Santé Publique, Créteil, France.
authors: Sylvie
authors: S
authors: Bastuji-Garin
authors: Université Paris 13, Sorbonne Paris Cité, EA2363 « Réponses cellulaires et fonctionnelles à l'hypoxie », U.F.R. SMBH, Bobigny, France; AP-HP, Hôpital Avicenne, Service de Physiologie, Explorations Fonctionnelles et Médecine du Sport, Bobigny, France.
authors: Jean-Paul
authors: JP
authors: Richalet
mesh_terms: D000328:Adult; D000532:Altitude Sickness; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012307:Risk Factors