Prediction Value of Bladder Deformity Index for Upper Urinary Tract Damage in Patients With Neurogenic Bladder

Aim: This study aimed to assess the predictive value of the Bladder Deformity Index (BDI) in determining upper urinary tract (UUT) damage among patients with neurogenic bladder (NB).

Methods: Clinical data of 132 NB patients admitted to the China Rehabilitation Research Center between January 2018 and December 2023 were retrospectively analyzed. Patients were categorized into UUT damage and normal UUT function groups based on the MRU and ultrasound grading systems for hydronephrosis, patients with the grade greater than or equal to I degree were considered to have UUTD. Patient demographics, biochemical parameters, and video-urodynamics (VUDS) findings were collected, and BDI was calculated. Independent sample t tests were employed to compare general characteristics and VUDS parameters between groups. Receiver operating characteristic (ROC) curves were utilized to evaluate the predictive capability of UUT damage.

Results: The study comprised 132 patients (86 males and 46 females) with an average NB duration of 7.37 ± 9.37 years (range: 0.2-44 years). UUT damage was present in 40.91% (n = 54) of patients. Significant differences (p < 0.05) were observed between the UUT damage and normal groups in terms of the duration of LUTS (9.98 ± 10.52 vs. 4.83 ± 7.32 years), creatinine levels (135.58 ± 110.51 vs. 57.66 ± 12.26 μmol/L), and BDI (103.28 ± 71.6 vs. 19.23 ± 15.03%). No significant differences were noted in age, bladder volume, or residual urine between the groups (p > 0.05). The AUC for the duration of LUTS, creatinine, and BDI were 0.691, 0.786, and 0.908, respectively, with a BDI Yoden index of 77%.

Conclusion: Long-term LUTS, elevated creatinine levels, and high BDI are associated with UUT damage. BDI demonstrates high sensitivity and specificity in diagnosing UUT damage, outperforming creatinine levels and NB duration. Patients with BDI values exceeding 77% are at a heightened risk of UUT damage. BDI facilitates quantitative evaluation of cystography and preliminary evaluation upper and lower urinary tract function in NB patients. Further research is warranted to validate BDI's feasibility in quantifying cystography and diagnosing UUT damage.

Trial registration: This study is retrospective and does not require clinical trial registration.