Background Critically ill patients with rheumatoid arthritis (RA) have high short-term mortality. The platelet-to-lymphocyte ratio (PLR) reflects RA inflammatory activity. We evaluated whether admission PLR is associated with 28- and 90-day mortality in critically ill patients with RA. Methods RA patients were identified from the MIMIC-IV database. Restricted cubic spline (RCS) Cox models characterized the PLR–mortality association and defined a log PLR threshold. Patients were stratified into low, middle, and high PLR groups using this threshold with a ± 0.3 margin (δ). Cumulative incidence of death was assessed using the Kaplan–Meier method. Piecewise Cox models were constructed with incremental adjustment. Subgroup analyses tested the consistency of PLR’s effect across different strata. Results Among 989 patients, 28- and 90-day mortality were 16.4% and 23.5%. RCS analysis showed a U-shaped association, with the lowest risk at log PLR = 4.725 and higher hazards toward both extremes. In piecewise Cox models, each + 1 log PLR was associated with lower mortality in the low PLR segment (28-day hazard ratio (HR) 0.59; 90-day HR 0.61) but higher risk in the high PLR segment (28-day HR 1.72; 90-day HR 1.67). Associations persisted after multivariable adjustment, with consistent subgroup trends. Conclusions Admission PLR is a significant prognostic marker in critically ill RA, demonstrating a U-shaped relationship with 28- and 90-day mortality. Both abnormally low and high PLR values were associated with higher mortality. <Table Float="No" ID="Taba"> <tgroup cols="2"> <colspec align="left" colname="c1" colnum="1" /> <colspec align="left" colname="c2" colnum="2" /> <tbody> <row> <entry align="left" nameend="c2" namest="c1"> Key Points • Admission PLR shows a U-shaped, independent association with 28- and 90-day mortality, with the lowest risk at log PLR 4.725 (~ PLR ≈112). • Threshold groups (PLR < ~ 84, 84 —153) and piecewise Cox models reveal decreasing risk below and increasing risk above the cutoff, persisting after multivariable adjustment. • Effects remain after multivariable adjustment and are consistent across clinical subgroups. • As a routine CBC metric, PLR enables simple early ICU risk stratification for RA, highlighting excess risk at both extremes. </entry> </row> </tbody> </tgroup> </Table>

Non-linear association of admission platelet-to-lymphocyte ratio with 28- and 90-day mortality in critically ill patients with rheumatoid arthritis: a retrospective cohort study

期刊论文
发表日期：

2025年12月9日

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Jing Yuan,
Wan-Zhu Liu,
Dian-Chen Wu,
Feng-Yun Jia,
Jia-Ying Yang,
Xi Cao,
Zhou Zhou,
Jun Tan

摘要

Background

Critically ill patients with rheumatoid arthritis (RA) have high short-term mortality. The platelet-to-lymphocyte ratio (PLR) reflects RA inflammatory activity. We evaluated whether admission PLR is associated with 28- and 90-day mortality in critically ill patients with RA.

Methods

RA patients were identified from the MIMIC-IV database. Restricted cubic spline (RCS) Cox models characterized the PLR–mortality association and defined a log PLR threshold. Patients were stratified into low, middle, and high PLR groups using this threshold with a ± 0.3 margin (δ). Cumulative incidence of death was assessed using the Kaplan–Meier method. Piecewise Cox models were constructed with incremental adjustment. Subgroup analyses tested the consistency of PLR’s effect across different strata.

Results

Among 989 patients, 28- and 90-day mortality were 16.4% and 23.5%. RCS analysis showed a U-shaped association, with the lowest risk at log PLR = 4.725 and higher hazards toward both extremes. In piecewise Cox models, each + 1 log PLR was associated with lower mortality in the low PLR segment (28-day hazard ratio (HR) 0.59; 90-day HR 0.61) but higher risk in the high PLR segment (28-day HR 1.72; 90-day HR 1.67). Associations persisted after multivariable adjustment, with consistent subgroup trends.

Conclusions

Admission PLR is a significant prognostic marker in critically ill RA, demonstrating a U-shaped relationship with 28- and 90-day mortality. Both abnormally low and high PLR values were associated with higher mortality.

Key Points

• Admission PLR shows a U-shaped, independent association with 28- and 90-day mortality, with the lowest risk at log PLR 4.725 (~ PLR ≈112).

• Threshold groups (PLR < ~ 84, 84 —153) and piecewise Cox models reveal decreasing risk below and increasing risk above the cutoff, persisting after multivariable adjustment.

• Effects remain after multivariable adjustment and are consistent across clinical subgroups.

• As a routine CBC metric, PLR enables simple early ICU risk stratification for RA, highlighting excess risk at both extremes.