OPINION article
Front. Neurol.
Sec. Stroke
Volume 16 - 2025 | doi: 10.3389/fneur.2025.1620259
Comment on "Association between systemic immune-inflammation index and post-stroke depression: a cross-sectional study of the NHANES 2005-2020" by Wang M et al
Provisionally accepted
Hongtao Luo
anqiang yang*- First People's Hospital of Yibin, Sichuan, China
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We read with great interest the paper by Wang et al., titled "The Relationship Between Systemic Immune Inflammatory Index and Post-stroke Depression: A Cross-sectional Study from NHANES 2005-2020", recently published in Frontiers in Neurology (1). This article addresses a significant clinical issue by examining the relationship between systemic immune-inflammatory index (SII) and post-stroke depression (PSD).However, after a thorough evaluation of the study design and data analysis methodologies, we would like to highlight a significant methodological concern that may potentially undermine the validity and interpretation of the results.Specifically, participants without a history of stroke were included in the "Post-stroke depression = No" group. Post-stroke depression (PSD) is inherently a stroke sequela. Since individuals without a stroke history do not develop post-stroke depression, their inclusion may introduce non-differential misclassification and this systematic error would attenuate effect estimates between systemic immune-inflammation index (SII) and PSD by inflating the reference group with individuals inherently incapable of developing the outcome. This issue may explain the relatively low prevalence of PSD reported in the study, which is much lower than the 27–62% prevalence typically observed among stroke survivors as previously reported by Zhou et al. (2) Limiting the analysis to individuals with a confirmed history of stroke would allow for a more accurate estimation of the association between SII and PSD, thereby improving the internal validity and clinical relevance of the study results.We thank the authors for their valuable contribution to this important area and hope that this opinion will help improve the research methods in the field of stroke-related mental outcomes in the future.
Keywords: post-stroke depression, Stroke, NHANES, systemic immune-inflammation index 6 (SII), Epidemiology
Received: 29 Apr 2025; Accepted: 22 Aug 2025.
Copyright: © 2025 Luo and yang. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: anqiang yang, First People's Hospital of Yibin, Sichuan, China
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