Systemic immune-inflammation index as a potential biomarker to monitor ulcerative colitis

Abstract

Objective

The treat-to-target strategy is recommended by Selecting Therapeutic Targets in Inflammatory Bowel Disease II (STRIDE-II) for treating ulcerative colitis (UC), and monitoring remission status is crucial during this management. The systemic immune-inflammation index (SII), defined as platelet * neutrophil/lymphocyte, is a complete blood count-based index reflecting the balance of immune and inflammatory status. This study aims to investigate the feasibility of SII for diagnosing UC and monitoring UC disease activity.

Methods

This study retrospectively analyzed patients with UC and controls. Relationships between SII and Mayo clinical score, Mayo Endoscopic Score (MES), and Nancy Histological Index (NHI) were evaluated.

Results

167 patients with UC and 106 controls were included. SII significantly increased in patients with UC and was closely correlated with the Mayo clinical score, MES, and NHI. SII diagnosed UC with a cut-off value of 619.1 × 10⁹/L (area under the curve = 0.861, p < 0.0001, sensitivity 79.64%, specificity 77.36%), evaluated clinical remission status with a cut-off value of 1068 × 10⁹/L (area under the curve = 0.691, p < 0.05, sensitivity 55.71%, specificity 81.48%), endoscopic improvement with a cut-off value of 981.3 × 10⁹/L (area under the curve = 0.819, p < 0.0001, sensitivity 65.22%, specificity 89.66%), and histological healing with a cut-off value of 689.3 × 10⁹/L (area under the curve = 0.898, p < 0.0001, sensitivity 88.89%, specificity 95.83%).

Conclusion

SII is a potential biomarker for diagnosing UC and monitoring UC disease severity, especially in evaluating mucosal and histological healing during the long-term management in treat-to-target strategy. However, further research is needed to confirm its usefulness and optimize its clinical application.

PLAIN LANGUAGE SUMMARY

Researchers studied an index calculated from a blood test, named the "systemic immune-inflammation index" (SII), to see if it can identify and track the activity of a bowel condition called ulcerative colitis (UC).

They reviewed health records of UC patients and compared them to people without this condition. They specifically checked if the SII test’s results aligned with other common tests that show the severity of UC.

People with UC tended to have higher SII results. The SII test results were consistent with other tests for UC. Specific scores from the SII test, like 619.1 × 10⁹/L, can indicate someone might have UC. What’s more, this test can give clues about inflammation in the bowel, saving some from more invasive tests like a colonoscopy or biopsy.

The SII test could be a promising way for doctors to diagnose UC and gauge its activity without needing more intrusive tests. However, more studies are required to fully trust this approach.

Keywords:

• systemic immune-inflammation index
• ulcerative colitis
• treat-to-target
• endoscopic improvement
• histological healing

Transparency

Declaration of funding

This paper was not funded.

Declaration of financial/other relationships

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Author contributions

Jin Yan contributed to the conception and design of the study, acquisition, analysis, and interpretation of data, and drafted the manuscript. Feihong Deng, Yuyong Tan, and Bingyi Zhou contributed to the acquisition and interpretation of data and critically revised the manuscript. Deliang Liu contributed to the conception and design of the study, interpretation of data, and critically revised the manuscript for important intellectual content.

Acknowledgements

None.

Ethics statement

Study approval statement: The study adheres to the Declaration of Helsinki and was approved by the Ethics Committee of the Second Xiangya Hospital of Central South University [No. 2019 S315].

Consent to participate statement: This is a retrospective study and therefore consent to participate statements are waived. It has been approved by the Ethics Committee of the Second Xiangya Hospital of Central South University.