Systemic Immune-Inflammation Index Was Significantly Associated with All-Cause and Cardiovascular-Specific Mortalities in Patients Receiving Peritoneal Dialysis

Abstract

Purpose

The prognosis of patients receiving peritoneal dialysis (PD) is associated with inflammation. Systemic immune-inflammation index (SII) is one of inflammatory markers, and the role in predicting clinical outcomes in PD patients is unclear. We aimed to investigate the relationship between the SII and all-cause and cardiovascular-specific mortalities in patients undergoing PD.

Patients and Methods

A total of 1419 PD patients from the First Affiliated Hospital of Sun Yat-sen University between January 1, 2007 and December 31, 2019 were retrospectively included at baseline, and the patients were followed up until November 31, 2021. SII was calculated as platelet count×neutrophil count/lymphocyte count. Kaplan–Meier curves and Cox proportional hazards regression models were used to determine the relationship between SII levels and all-cause and cardiovascular-specific mortalities.

Results

During follow-up (median period was 42 months), 321 patients died (171 died of cardiovascular disease). With adjustment for the potential confounding factors, each 1-SD increase in the SII was associated with 20.2% increase in all-cause mortality (hazard ratio [HR]: 1.202, 95% confidence interval [CI]: 1.088–1.327, P<0.001) and 28.0% increase in cardiovascular-specific mortality (HR: 1.280, 95% CI: 1.126–1.456, P<0.001). High SII (vs low SII) was significantly associated with increased risks of all-cause mortality (HR: 1.391, 95% CI: 1.066–1.815, P-value: 0.015) and cardiovascular-specific mortality (HR: 1.637, 95% CI: 1.185–2.261, P-value: 0.003). Subgroups analyses showed similar results for those younger than 65-year-old only.

Conclusion

Elevated SII level was independently associated with increased risks of all-cause and cardiovascular-specific mortalities in PD patients, especially for those younger than 65-year-old.

Keywords:

• all-cause mortality
• cardiovascular mortality
• peritoneal dialysis
• systemic immune-inflammation index

Abbreviations

SII, systemic immune-inflammation index; PD, peritoneal dialysis; HR, hazard ratio; CI, confidence interval; CKD, chronic kidney disease; ESRD, end-stage renal disease; CVD, cardiovascular disease; HD, hemodialysis; ROC, receiver operating curve; DM, diabetes mellitus; WBC, white blood cell; hs-CRP, high-sensitivity C-reactive protein; eGFR, estimated glomerular filtration rate; NLR, neutrophil-to-lymphocyte ratio; PLR, platelet-to-lymphocyte ratio.

Data Sharing Statement

The datasets generated and analyzed during the current study are not publicly available but are available from the corresponding author on reasonable request.

Ethics Approval and Informed Consent

This study was approved by the Research Ethics Committee of The First Affiliated Hospital of Sun Yat-sen University and was in accordance with the Declaration of Helsinki. Informed consent was obtained from all individual participants included in the study.

Acknowledgments

We thank all the participants, doctors and nurses of our PD center.

Disclosure

The authors report no conflicts of interest in this work.

Additional information

Funding

The present study was supported by the National Natural Science Foundation of China [grant number 82000677, 82000640]; the NHC Key Laboratory of Clinical Nephrology (Sun Yat-Sen University) and Guangdong Provincial Key Laboratory of Nephrology [grant number 2020B1212060028]; and the Guangdong Basic and Applied Basic Research Foundation [grant number 2019B1515120075, 2022A1515012532].