Association between C-reactive protein-triglyceride glucose index and overactive bladder: A population-based study from NHANES 2005–2010 and 2015–2018

Overactive bladder (OAB) is a common urological condition with significant impacts on quality of life and healthcare burden. Chronic inflammation and insulin resistance have been independently linked to bladder dysfunction. The C-reactive protein-triglyceride glucose index (CTI), a novel composite marker reflecting both inflammatory and metabolic status, may provide additional value in assessing OAB risk, but has not been previously studied in this context. We conducted a cross-sectional analysis using data from National Health and Nutrition Examination Survey 2005-2010 and 2015-2018. OAB was defined based on self-reported symptoms of urgency incontinence and nocturia. CTI was calculated as 0.412 × ln (CRP) + TyG, where TyG = ln [fasting triglyceride (mg/dL) × fasting glucose (mg/dL)/2]. Survey-weighted multivariable logistic regression models were used to assess the association between CTI and OAB. Subgroup, interaction, and generalized additive model analyses were performed to explore potential effect modification and nonlinear trends. Discriminative performance was evaluated using receiver operating characteristic curves. A total of 9390 adults were included. Higher CTI levels were significantly associated with increased odds of OAB. In fully adjusted models, each unit increase in CTI was associated with a 17% higher risk of OAB (OR = 1.17, 95% CI: 1.06-1.28, P = .002). Compared to the lowest CTI quartile, the highest quartile showed a 50% increased risk of OAB (OR = 1.50, 95% CI: 1.17-1.93, P = .002). The association persisted across subgroups, with stronger effects observed in females, younger adults, and participants with lower poverty income ratio. Interaction tests confirmed significant effect modification by age (P for interaction < .001) and socioeconomic status (P = .02). Generalized additive model analysis demonstrated a nonlinear positive trend between CTI and OAB prevalence. In receiver operating characteristic analysis, CTI showed superior discriminative ability (AUC = 0.607) compared to CRP (AUC = 0.588) and TyG (AUC = 0.569). CTI is independently associated with the presence of OAB in a representative US adult population. As a composite marker of metabolic and inflammatory burden, CTI may serve as a useful tool for identifying individuals at elevated risk of OAB, particularly among younger and socioeconomically disadvantaged groups.