An Individualized Treatment Approach Based onAbscess Size in Renal Abscesses: A Retrospective Study

Objective: We aimed to evaluate the impact of the abscess-to-kidney surface area ratio, inflammatory biomarkers, and comorbidities on treatment decisions in renal abscess management, beyond the traditional size-based approach. Methods: This retrospective cohort study included 41 adult patients with radiologically confirmed renal or perirenal abscesses between 2016 and 2025. Patients were categorized into three groups: medical therapy only, minimally invasive drainage, and invasive surgical intervention. Abscess size, contact surface ratio, and laboratory parameters (e.g., neutrophil-to-lymphocyte ratio (NLR), albumin) were analyzed. Multinomial logistic regression and subgroup analyses were performed to identify predictors of treatment modality. Results: The mean abscess diameter was significantly different across treatment groups (p < 0.001), with a higher rate of invasive interventions in abscesses >60% of the kidney surface. Elevated NLR was an independent predictor of invasive treatment in the multivariate model. While lower albumin levels were observed in univariate analysis among patients requiring invasive therapy, this association was not independent in the adjusted model. Diabetes mellitus was significantly more prevalent among patients requiring invasive therapy (p = 0.002). Among patients with 30–60% surface area involvement, NLR was significantly higher in those requiring surgical intervention (p = 0.014). The regression model demonstrated good predictive performance. Conclusions: A multidimensional treatment algorithm that integrates abscess-to-kidney surface area ratio, systemic inflammatory response, and comorbid conditions may guide optimal therapy for renal abscesses. Particularly in intermediate-sized abscesses, laboratory markers such as NLR and albumin may help identify candidates for early intervention, potentially avoiding delayed or insufficient treatment.