Relationship Between SII Levels and OAB Incidence- A Cross-Sectional Study Based on NHANES 2005-2020

Objective This study aimed to investigate the relationship between the Systemic Inflammatory Index (SII) among US adults from 2005 to 2020 and the incidence of Overactive Bladder (OAB). Additionally, a predictive model for OAB risk was constructed based on SII. Methods This cross-sectional study involved 11,427 participants from the National Health and Nutrition Examination Survey (NHANES) spanning from 2005 to 2020. SII was calculated based on peripheral blood results, while data on urinary conditions were assessed using the Overactive Bladder Symptom Score (OABSS) to determine the presence of OAB. Participants were stratified into two groups based on the presence or absence of OAB, and baseline characteristics were compared. Then, the correlation between SII and OAB was explored using univariate and multivariate logistic regression analyses coupled with smoothed curve fitting. A multifactorial Logistic Regression model was established by selecting variables associated with OAB incidence, incorporating clinical significance, and constructing a nomogram. Lastly, the predictive ability of the nomogram for identifying OAB was evaluated using ROC curves, calibration curves, and Decision Curve Analysis (DCA). Results Among the examined 11,427 samples, individuals with OAB exhibited higher SII levels (475.59 (326.49–683.89) vs. 435.00 (315.00–615.57), p < 0.01). Both univariate and multivariate Logistic Regression analyses revealed a positive correlation between SII/1000 and the incidence of OAB. Moreover, smooth curve fitting demonstrated a non-linear positive correlation between OAB and SII/1000 (P-nonlinear < 0.05). Finally, our established nomogram could predict the risk of OAB (AUC = 0.754), holding clinical decision-making significance. Conclusion A positive correlation was identified between SII and the risk of OAB among American adults, highlighting the predictive value of SII for OAB incidence. However, larger-scale prospective studies are warranted to validate our findings.