Researchers using the Third China National Stroke Registry (CNSR-III) have identified the systemic inflammatory response index (SIRI) as the most reliable composite inflammatory marker for predicting stroke recurrence. The study, published in 2026, suggests these markers can help identify high-risk patients who may require closer monitoring after an initial event.
Inflammation is increasingly recognized as a primary driver of stroke pathophysiology. While various composite inflammatory markers have been proposed to help clinicians predict outcomes, their comparative effectiveness has remained understudied until now. A large prospective cohort study has sought to clarify which of these tools provides the most accurate prognosis for patients recovering from ischaemic stroke or transient ischaemic attack (TIA).
SIRI and the CNSR-III Registry Findings
Analyzing 14,476 participants aged 18 and older from the Third China National Stroke Registry (CNSR-III), researchers evaluated six specific composite inflammatory markers: SIRI, SII, PIV, PLR, NLR, and MLR. The goal was to determine which marker best predicted one-year stroke recurrence and other adverse outcomes.
The results showed that all six markers were positively associated with stroke recurrence, as well as mortality, poor functional outcomes, and composite vascular events. However, SIRI emerged as the strongest predictor of recurrence. When researchers utilized XGBoost models, the area under the curve reached its highest value of 0.624 upon the addition of SIRI, compared to a baseline of 0.598.
- 1,403 patients (9.7%) experienced recurrent stroke
- 1,300 patients (9.0%) had ischaemic stroke
- 1,484 patients (10.3%) suffered composite vascular events
- 483 patients (3.3%) died
- 2,865 patients (21.7%) had poor functional outcomes, defined as a modified Rankin Scale score of 2 to 6
Differentiating Inflammatory Markers and Cardiac Impact
While the CNSR-III data focuses on stroke recurrence, other research has explored how specific inflammatory markers influence the heart’s physical structure. A 2-sample Mendelian randomization study using data from the UK Biobank (n = 16,923) examined the causal relationship between markers like C-reactive protein (CRP), interleukin-6 (IL-6), and myeloperoxidase (MPO) and left ventricular (LV) parameters.
Unlike the broad predictive value of SIRI in stroke recurrence, the UK Biobank analysis found a very specific causal link: increased CRP levels were associated with decreased LV mass. Specifically, a higher standard deviation of genetically-predicted CRP levels correlated with a 0.13 ± 0.06 g lower LV mass. Notably, the study found no causal relationships between IL-6 or MPO and LV parameters.
Predicting Risk After Transient Ischaemic Attack
The challenge of recurrence is particularly acute for those who have experienced a transient ischaemic attack (TIA), which precedes a full stroke in nearly 20% of patients. Beyond the composite markers used in the CNSR-III study, other molecular markers are being explored to refine these predictions.
Integrating these metabolomic markers with conventional predictors could potentially increase the accuracy of risk assessments and create new opportunities for preventative intervention.
Clinical Application and Limitations
The ability to stratify risk using markers like SIRI allows clinicians to identify which patients are most likely to suffer a second stroke, potentially triggering more aggressive monitoring or preventative care. However, the nature of the CNSR-III research is observational, meaning that while a strong association exists, causality cannot be established.
The divergence between these studies—one focusing on composite indices for recurrence and another on the genetic causality of heart mass—underscores the complexity of inflammation in vascular health. While SIRI provides a powerful predictive tool for the timing and likelihood of a second stroke, the CRP findings suggest that inflammation also physically alters the geometry of the heart.
Further research is required to validate the causal links between inflammatory markers and cardiac function, and to determine if targeting these markers can actually reduce the recurrence rates identified in the registry data.
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