Relationship between the Systemic ImmuneInflammation Index and Muscle Strength in Patients with Chronic Kidney Disease: A CrossSectional Study of Data from NHANES 2011–2014
Qianqian Zhang, Zhen Jia, Huijuan Hou, Xiangdong YangIntroduction:
This study aimed to determine the relationship between Systemic Immune-Inflammation Index (SII) and muscle strength in patients with CKD.
Methods:
This cross-sectional study examined adults with CKD using data from the National Health and Nutrition Examination Survey (2011–2014). The SII was calculated as: platelet count × neutrophil count/lymphocyte count. Muscle strength was determined from measurements of handgrip strength. Multivariate logistic regression and additional methods were used to assess the relationship between SII and muscle strength.
Results:
We examined 1620 patients with CKD (mean age: 61.4 years; 47% male). The overall prevalence of low muscle strength was 12.04%, and curve fitting indicated a positive, linear relationship between SII and low muscle strength. However, multivariate logistic regression analysis indicated that this relationship was not significant after adjustment for multiple confounders (odds ratio: 1.01, 95% CI: 0.99–1.02). These results were robust, and subgroup analyses showed no interactions.
Discussion:
Inflammation, malnutrition, and chronic comorbidities can affect muscle metabolism in CKD patients. The relationship between SII and low muscle strength is complex and variable. Although SII reflects systemic immune activation, it is less capable than markers, such as IL-6 and CRP, in directly capturing tissue-level inflammation that leads to muscle atrophy.
Conclusion:
There was no significant association between SII and low muscle strength in patients with CKD, even after adjustment for nutritional status, comorbidities, and renal function. Although previous studies showed that CKD patients had increased inflammatory responses and decreased muscle strength, our results suggest underlying complexities may confound this relationship.