Association between systemic inflammatory markers and all-cause mortality in patients with stroke: A prospective study using data from the UK Biobank

Abstract

Background and aims

The systemic immune-inflammation index (SII), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and lymphocyte-to-monocyte ratio (LMR) are novel inflammatory biomarkers used to determine various disease prognoses. However, the effects of these systemic inflammatory markers on all-cause mortality in patients with stroke remain unclear.

Methods

We used data from the UK Biobank for this prospective analysis. Overall, 6,020 eligible individuals were included. Over a median follow-up of 13.4 years, 1,233 participants died. We examined the effects of systemic inflammatory markers on all-cause mortality using random survival forest (RSF) and Cox proportional hazards models. Covariate adjustments in the Cox model, selected by RSF, included age, sex, body mass index (BMI), Townsend deprivation index, smoking status, alcohol intake frequency, sleep duration, diabetes, and malignant neoplasms.

Results

In the marginal effect plots and restricted cubic spline analysis for systemic inflammatory markers, LMR exhibited a linear negative correlation, NLR showed a linear positive correlation, and SII and PLR demonstrated a U-shaped association. After covariates were adjusted, the all-cause mortality risk increased by 14 % for LMR <4 (hazards ratio [HR]: 1.14, 95 % confidence interval [CI]: 1.01–1.29; p= 0.03), by 26 % for NLR ≥2 (HR: 1.26; 95 % CI: 1.11–1.43; p < 0.001),by 26 % for PLR ≥175 (HR: 1.26; 95 % CI: 1.07–1.47; p < 0.001), and by 31 % for SII ≥526 (HR: 1.31; 95 % CI, 1.16–1.47; p= 0.014). In addition, sensitivity analyses, excluding participants who had been followed-up for <2 years and those with malignant neoplasms, yielded results consistent with those of previous research.

Conclusion

SII, NLR, PLR, and LMR significantly correlate with all-cause mortality in stroke patients. Thresholds established by the RSF model could potentially refine prognostic decision-making in stroke care.