CRP and susceptibility to pneumonia measurement: In the univariate logistic regression analysis, S1P concentration was predictive of pneumonia with odds ratio of 1.27 (95% CI: 1.17–1.41; p < 0.0001) and CRP levels was predictive of pneumonia with odds ratio of 1.59 (95% CI: 1.35–1.99, 1.43–3.51 p < 0.0001).