Association between systemic immune inflammation index, systemic inflammation response index and adult psoriasis: evidence from NHANES

Abstract

Background: The systemic immune-inflammation index (SII) and systemic inflammation response index (SIRI) are both novel biomarkers and predictors of inflammation. Psoriasis is a skin disease characterized by chronic inflammation. This study aimed to investigate the potential association between SII, SIRI, and adult psoriasis.

Methods: Data of adults aged 20 to 80 years from the National Health and Nutrition Examination Survey (NHANES) (2003-2006, 2009-2014) were utilized. The K-means method was used to group SII and SIRI into low, medium, and high-level clusters. Additionally, SII or SIRI levels were categorized into three groups: low (1^st-3^rd quintiles), medium (4^th quintile), and high (5^th quintile). The association between SII-SIRI pattern, SII or SIRI individually, and psoriasis was assessed using multivariate logistic regression models. The results were presented as odds ratios (ORs) and confidence intervals (CIs). Restricted cubic spline (RCS) regression, subgroup, and interaction analyses were also conducted to explore the potential non-linear and independent relationships between natural log-transformed SII (lnSII) levels or SIRI levels and psoriasis, respectively.

Results: Of the 18208 adults included in the study, 511 (2.81%) were diagnosed with psoriasis. Compared to the low-level group of the SII-SIRI pattern, participants in the medium-level group had a significantly higher risk for psoriasis (OR = 1.40, 95% CI: 1.09, 1.81, p-trend = 0.0031). In the analysis of SII or SIRI individually, both SII and SIRI were found to be positively associated with the risk of psoriasis (high vs. low group OR = 1.52, 95% CI: 1.18, 1.95, p-trend = 0.0014; OR = 1.48, 95% CI: 1.12, 1.95, p-trend = 0.007, respectively). Non-linear relationships were observed between lnSII/SIRI and psoriasis (both p-values for overall < 0.05, p-values for nonlinearity < 0.05). The association between SII levels and psoriasis was stronger in females, obese individuals, people with type 2 diabetes, and those without hypercholesterolemia.

Conclusion: We observed positive associations between SII-SIRI pattern, SII, SIRI, and psoriasis among U.S. adults. Further well-designed studies are needed to gain a better understanding of these findings.

Keywords: NHANES; adults; psoriasis; systemic immune-inflammation index; systemic inflammation response index.

Figure 1

Flow chart of participant selection. BMI, body mass index; NHANES, National Health and Nutrition Examination Survey; PIR, poverty income ratio; SII, systemic immune inflammation index; SIRI, systemic inflammation response index.

Figure 2

Visualization of k-means clustering using t-SNE for NHANES participants (2003-2006, 2009-2014, n = 18,208) based on SII and SIRI levels. Three sub-groups (low-, medium-, and high-level groups) were identified based on the combination of SII and SIRI levels. NHANES, National Health and Nutrition Examination Survey; SII, systemic immune–inflammation index; SIRI, systemic inflammation response index; t-SNE, t-Distributed Stochastic Neighbor Embedding.

Figure 3

Distributions of SII and SIRI levels (10³ cells/μL) and dose-response curves of SII and SIRI levels in relation to psoriasis in the NHANES follow-up study from 2003–2006 and 2009–2014 cycles (n = 18,208). Distributions of SII and SIRI levels and adjusted ORs with 95% CIs for (A) SII levels, (B) SIRI levels. ORs for SII/SIRI levels were adjusted for gender, age, race/ethnicity, education levels, marital status, BMI, alcohol intake, serum cotinine, family PIR, hypertension, type 2 diabetes, and hypercholesterolemia. BMI, body mass index; CI, confidence interval; NHANES, National Health and Nutrition Examination Survey; OR, odds ratio; PIR, poverty income ratio; SII, systemic immune–inflammation index; SIRI, systemic inflammation response index.

Figure 4

Forest plot depicting subgroup analysis of the association between lnSII/SIRI and psoriasis. The ORs were calculated using multivariate logistic regression models with adjustment for gender, age, race/ethnicity, education levels, marital status, BMI, alcohol intake, serum cotinine, family PIR, hypertension, type 2 diabetes, and hypercholesterolemia, except for the variable used for stratification. BMI, body mass index; ORs, Odds ratios; PIR, poverty income ratio; SII, systemic immune–inflammation index; SIRI, systemic inflammation response index.