Association between the systemic inflammation response index and mortality in cancer survivors based on NHANES 2001-2018.

Inflammatory responses play a critical regulatory role in the development and progression of cancer. As a novel inflammatory marker, the association between the systemic inflammation response index (SIRI) and mortality among cancer survivors remains unclear. This study aims to elucidate the relationship between the SIRI and all-cause mortality among cancer survivors in the United States. This study utilized continuous data from the National Health and Nutrition Examination Survey (NHANES) from 2001 to 2018, with follow-up data available through December 31, 2019. All patients were divided into four groups based on their SIRI values. Cox proportional-hazards regression models, Kaplan-Meier survival curves, and restricted cubic splines (RCS) combined with Cox proportional hazards models were applied to investigate the relationship between SIRI and cancer survival rates. Additionally, sensitivity and subgroup analyses were conducted to test the robustness of the results. A total of 3733 cancer survivors were included in this study. During a median follow-up period of 119 months, 1217 deaths occurred, resulting in an all-cause mortality rate of 32.57%. The results of the Cox proportional-hazards regression model showed that compared to the low SIRI group, the highest SIRI group had a higher risk of mortality (HR 1.52; 95% CI 1.28, 1.81). Additionally, the Kaplan-Meier curve indicated that participants with higher SIRI values had a higher all-cause mortality rate. The RCS model indicated a nonlinear positive correlation between SIRI values and all-cause mortality. The sensitivity analysis demonstrated that the study results remained consistent without significant changes after excluding participants who died within the first two years of follow-up. The subgroup analysis showed that SIRI was associated with all-cause mortality across different demographic characteristics (including gender, marital status, history of hypertension, and diabetes) as well as cancer types (lung cancer, breast cancer, colorectal cancer, skin cancer, and prostate cancer). In conclusion, our study reveals a significant association between SIRI and all-cause mortality among cancer survivors in the United States, which helps identify cancer survivors at higher risk of death and highlights its important prognostic value in oncology.