Predictive value of serum calcium ion level in patients with colorectal cancer: A retrospective cohort study

Figure 3 Overall survival and progression-free survival stratified by Δ calcium value and serum calcium ion level on the first day of postoperative period. A: Overall survival (OS) stratified by delta serum calcium (δCa²⁺) value (P = 0.0079, hazard ratio [HR] = 1.954); B: OS stratified by serum Ca²⁺ ion level on the first day of postoperative period (Ca²⁺-first postoperative day) (P = 0.0007, HR = 0.415); C: Progression-free survival (PFS) stratified by δCa²⁺ value (P = 0.0007, HR = 2.385); D: PFS stratified by Ca²⁺-first postoperative day (P = 0.0003, HR = 0.3867).