National Center for Biotechnology Information NCBI NLM MEDLINE humans pubmed abstract nih national institutes of health national library of medicine prognosis treatment outcome research support non-u.s. gov't female male linear models severity of illness index Cohort Studies Proportional Hazards Models multivariate analysis predictive value of tests validation study roc curve calibration risk assessment / methods investigators=[] affs=[]) pmid:27227988 pmc4881958 doi:10.1371/journal.pone.0153527 julius sim lucy teece collabauthor(name='soࠢs study team' oxygen / therapeutic use stroke / diagnosis* stroke / mortality*