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

Figure 1 Receiver operating characteristic curve of serum calcium ion-related indicators to predict outcome. δCa²⁺: Delta serum calcium; AUC: Area under the receiver operating characteristic curve; Ca²⁺-baseline: Baseline serum calcium ion levels; Ca²⁺-first postoperative day: Serum calcium ion level on the first day of postoperative period.

Figure 2 Restricted cubic spline curves for serum calcium ion level on the first day of the postoperative period in colorectal cancer. Ca²⁺-first postoperative day: Serum calcium ion level on the first day of postoperative period; CI: Confidence interval.

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).

Figure 4 Nomograph of the model composed of T stage, N stage, and serum calcium level on the first postoperative day. CaFPD: Calcium level on the first postoperative day.

Figure 5  Calibration curves to predict 1-year, 3-year, and 5-year overall survival.

Figure 6 Decision curve analyses with clinical net benefits of the nomogram at 1 year, 3 years, and 5 years. A: Decision curve analyses with clinical net benefits of the nomogram at 1 year; B: Decision curve analyses with clinical net benefits of the nomogram at 3 years; C: Decision curve analyses with clinical net benefits of the nomogram at 5 years.