Cox regression analysis and nomogram establishment for OS
REGRESSION
In the prognostic analysis of OS, univariate and multivariate Cox regression analyses were applied, the proportional hazard hypothesis test (PH) was applied to evaluate prognostic factors, and factors with P-values < 0.05 in univariate Cox analysis were added to a multivariate Cox regression model to detect independent prognostic indicators. Based on the results of the multivariate Cox analysis of the training cohort, nomograms were created that incorporated all the independent prognostic factors to predict patients’ risk of living shorter than 1-, 3-, or 5-year. Every variable was linked to a specific point on a horizontal line, the risk score of each patient can be obtained by adding these points together and 1-, 3-, and 5 years OS rates can be anticipated. The individual risk score of each patient in the training cohort was calculated, according to which patients were divided into either low-risk, medium-risk, or high-risk groups by X-tile software (version 3.6.1).