Integrative Diagnostic Model Combining Urinary Biomarkers and Clinical Parameters to Improve Diagnostic Performance in Interstitial Cystitis/Bladder Pain Syndrome.

Background and objective: Interstitial cystitis/bladder pain syndrome (IC/BPS) is a chronic condition characterized by pelvic pain and urinary symptoms that overlap with other urological disorders, making diagnosis challenging. Current diagnostic approaches are often subjective and inconsistent. This study develops and internally validates a multivariable diagnostic prediction model that combines urinary biomarkers and clinical parameters to improve the diagnostic accuracy for IC/BPS. Methods: Data from 385 participants (344 IC/BPS patients and 41 controls) who underwent cystoscopic hydrodistension and videourodynamic studies were analyzed. Urine samples were analyzed for inflammatory cytokines and oxidative stress markers using multiplex and enzyme-linked immunosorbent assays. Clinical parameters included bladder pain (visual analog scale [VAS]) and functional bladder capacity (3-d voiding diary). The participants were randomly divided into training (70%) and testing (30%) sets. Logistic regression with stepwise selection was used to develop diagnostic models. Key findings and limitations: Urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) showed the highest discriminative ability among individual biomarkers (area under the receiver operating characteristic curve [AUROC] = 0.838). The two-marker model combining 8-OHdG and tumor necrosis factor-alpha (TNF-α) yielded AUROC values of 0.958 (training) and 0.952 (testing). The final integrative model incorporating 8-OHdG, TNF-α, and VAS achieved near-perfect diagnostic performance (AUROC = 0.997 in training and 0.997 in testing), with 96% accuracy, 96% sensitivity, and 92% specificity. Conclusions and clinical implications: This integrative, noninvasive diagnostic model demonstrates excellent diagnostic performance and offers a scalable, objective, and patient-friendly alternative to traditional invasive testing. Incorporation of urinary oxidative stress and inflammatory biomarkers into clinical pain scores may facilitate earlier and more accurate IC/BPS diagnosis in routine practice. Patient summary: We found that combination of specific urine markers with pain scores can diagnose interstitial cystitis/bladder pain syndrome accurately, without invasive tests. This diagnostic model reduces reliance on patients' subjective symptom reporting, helping doctors confirm the disease earlier and more confidently, while making the diagnostic process more comfortable for patients.