Objective:To explore the relationship between serum triglyceride to high-density lipoprotein cholesterol (TG/HDL-C) ratio, interleukin-17C (IL-17C), and C-C motif chemokine ligand-26 (CCL-26) with clinical symptoms and suicide ideation in patients with major depressive disorder.Methods:A total of 186 patients with major depressive disorder (major depressive disorder group) admitted to the Heze Third People′s Hospital from January 2021 to December 2024 were prospectively selected, including 66 males and 120 females, aged 19-68 (36.5±11.9) years old. In addition, 93 healthy and mentally healthy volunteers (control group) with matched gender and age were selected, including 38 males and 55 females, aged 19-65 (35.6±9.5) years old. According to the presence of suicidal ideation, patients with major depressive disorder were divided into a suicidal ideation group ( n=80) and a non-suicidal ideation group ( n=106). Serum TG/HDL-C ratio, IL-17C and CCL-26 levels of all participants were measured. Clinical symptoms were assessed using the 17-Item Hamilton Depression Rating Scale (HAMD 17), 14-Item Hamilton Anxiety Rating Scale (HAMA), and Pittsburgh Sleep Quality Index (PSQI). Spearman's rank correlation analysis was performed to evaluate associations between serum markers and clinical scores. Generalized additive models were used to assess nonlinear correlations. Multivariate unconditional logistic regression was conducted to identify independent risk factors for suicidal ideation. A nomogram prediction model was constructed. Model fit was evaluated with the H-L test, the area under the curve (AUC) of the receiver operating characteristic (ROC) curve assessed predictive ability, the C-index evaluated discrimination, calibration curves assessed agreement, and decision curve analysis assessed clinical utility. Results:Compared with the control group, the serum TG/HDL-C ratio, IL-17C level, HAMD 17 score, HAMA score and PSQI score increased in the severe depression group, while CCL-26 level decreased ( P<0.001). Serum TG/HDL-C ratio and IL-17C levels were positively correlated with HAMD 17, HAMA and PSQI scores ( r s=0.74, 0.74, 0.75, 0.78, 0.78, 0.79; all P<0.001), while CCL-26 levels were negatively correlated with these scores ( r s=-0.62, -0.63, -0.65, all P<0.001). There were nonlinear relationships between serum TG/HDL-C ratio, IL-17C, CCL-26 levels and the clinical symptom scores ( P<0.001). Among the 186 major depressive disorder patients, the incidence of suicidal ideation was 43.01% (80/186). History of attempted suicide, increased HAMD 17 score, increased HAMA score, increased PSQI score, elevated TG/HDL-C ratio and elevated IL-17C were independent risk factors for suicidal ideation in patients with severe depression ( OR (95% CI)=10.89 (2.27-52.25), 1.81 (1.19-2.74), 1.23 (1.08-1.40), 1.53 (1.15-2.02), 6.64 (2.71-16.24), 1.46 (1.18-1.81) respectively), elevated CCL-26 were independent protective factor( OR (95% CI)=0.22 (0.11-0.43)). Constructing a column chart prediction model for suicidal ideation in patients with severe depression based on the independent factors affecting suicidal ideation in patients with severe depression mentioned above, the AUC for predicting suicidal ideation in patients with severe depression is 0.93 (95% CI:0.88-0.96), and the C-index is 0.93 (95% CI:0.92-0.93). The decision curve showed that the predicted probability was consistent with the ideal curve, and when the threshold probability was greater than 0.10, the clinical net benefit was greater than 0. Conclusion:Elevated serum TG/HDL-C ratio and IL-17C levels, as well as decreased CCL-26 levels, are associated with depression, anxiety, sleep disorders, and suicidal ideation in patients with severe depression. The column chart prediction model based on serum TG/HDL-C ratio, IL-17C and CCL-26 levels has high predictive value for suicidal ideation.

Objective:To explore the relationship between serum triglyceride to high-density lipoprotein cholesterol (TG/HDL-C) ratio, interleukin-17C (IL-17C), and C-C motif chemokine ligand-26 (CCL-26) with clinical symptoms and suicide ideation in patients with major depressive disorder.Methods:A total of 186 patients with major depressive disorder (major depressive disorder group) admitted to the Heze Third People′s Hospital from January 2021 to December 2024 were prospectively selected, including 66 males and 120 females, aged 19-68 (36.5±11.9) years old. In addition, 93 healthy and mentally healthy volunteers (control group) with matched gender and age were selected, including 38 males and 55 females, aged 19-65 (35.6±9.5) years old. According to the presence of suicidal ideation, patients with major depressive disorder were divided into a suicidal ideation group ( n=80) and a non-suicidal ideation group ( n=106). Serum TG/HDL-C ratio, IL-17C and CCL-26 levels of all participants were measured. Clinical symptoms were assessed using the 17-Item Hamilton Depression Rating Scale (HAMD 17), 14-Item Hamilton Anxiety Rating Scale (HAMA), and Pittsburgh Sleep Quality Index (PSQI). Spearman's rank correlation analysis was performed to evaluate associations between serum markers and clinical scores. Generalized additive models were used to assess nonlinear correlations. Multivariate unconditional logistic regression was conducted to identify independent risk factors for suicidal ideation. A nomogram prediction model was constructed. Model fit was evaluated with the H-L test, the area under the curve (AUC) of the receiver operating characteristic (ROC) curve assessed predictive ability, the C-index evaluated discrimination, calibration curves assessed agreement, and decision curve analysis assessed clinical utility. Results:Compared with the control group, the serum TG/HDL-C ratio, IL-17C level, HAMD 17 score, HAMA score and PSQI score increased in the severe depression group, while CCL-26 level decreased ( P<0.001). Serum TG/HDL-C ratio and IL-17C levels were positively correlated with HAMD 17, HAMA and PSQI scores ( r s=0.74, 0.74, 0.75, 0.78, 0.78, 0.79; all P<0.001), while CCL-26 levels were negatively correlated with these scores ( r s=-0.62, -0.63, -0.65, all P<0.001). There were nonlinear relationships between serum TG/HDL-C ratio, IL-17C, CCL-26 levels and the clinical symptom scores ( P<0.001). Among the 186 major depressive disorder patients, the incidence of suicidal ideation was 43.01% (80/186). History of attempted suicide, increased HAMD 17 score, increased HAMA score, increased PSQI score, elevated TG/HDL-C ratio and elevated IL-17C were independent risk factors for suicidal ideation in patients with severe depression ( OR (95% CI)=10.89 (2.27-52.25), 1.81 (1.19-2.74), 1.23 (1.08-1.40), 1.53 (1.15-2.02), 6.64 (2.71-16.24), 1.46 (1.18-1.81) respectively), elevated CCL-26 were independent protective factor( OR (95% CI)=0.22 (0.11-0.43)). Constructing a column chart prediction model for suicidal ideation in patients with severe depression based on the independent factors affecting suicidal ideation in patients with severe depression mentioned above, the AUC for predicting suicidal ideation in patients with severe depression is 0.93 (95% CI:0.88-0.96), and the C-index is 0.93 (95% CI:0.92-0.93). The decision curve showed that the predicted probability was consistent with the ideal curve, and when the threshold probability was greater than 0.10, the clinical net benefit was greater than 0. Conclusion:Elevated serum TG/HDL-C ratio and IL-17C levels, as well as decreased CCL-26 levels, are associated with depression, anxiety, sleep disorders, and suicidal ideation in patients with severe depression. The column chart prediction model based on serum TG/HDL-C ratio, IL-17C and CCL-26 levels has high predictive value for suicidal ideation.