fig1

Figure 1. Correlation matrix among the Six LASSO-selected predictors. This heatmap presents pairwise correlation coefficients among the six predictors retained following correlation-based filtering and LASSO selection (anion gap, chloride, mechanical ventilation, pulmonary infection, total bilirubin, and urea). Correlation values are annotated in each cell, and the color gradient indicates both the direction and magnitude of correlations.