使用S-G nomogram診斷女性膀胱出口阻塞之外部驗證

麥倖嘉¹、吳俊賢^1,4,5,6、吳振宇^1,4、郭威廷^1,5,6、

李彥羲^2,5,6、蔡佳龍³、林嘉祥^1,6

¹義大醫院泌尿科；²義大癌治療醫院泌尿科；³義大大昌醫院泌尿科；⁴義守大學護理學系；

⁵義守大學生物技術與化學工程研究所；⁶義守大學醫學系

External Validation of Solomon-Greenwell Nomogram for Diagnosing Female Bladder Outlet Obstruction

Hsing-Chia Mai ¹、Chun-Hsien Wu ^1,4,5,6、Richard C. Wu ^1,4、

Wade Wei-Ting Kuo ^1,5,6、Yen-Hsi, Lee ^2,5,6、Chia-Lung Tsai ³、Victor C. Lin ^1,6

¹. Department of Urology, E-DA Hospital, Kaohsiung, Taiwan

². Department of Urology, E-DA Cancer Hospital, Kaohsiung, Taiwan

³. Department of Urology, E-DA Dachang Hospital, Kaohsiung, Taiwan

⁴. Department of Nursing, I-Shou University, Kaohsiung, Taiwan

⁵. Institute of Biotechnology and Chemical Engineering, I-Shou University, Kaohsiung, Taiwan

⁶. School of Medicine, College of Medicine, I-Shou University, Kaohsiung, Taiwan

Purpose:

Female bladder outlet obstruction (BOO) is an overlooked disorder. Currently, there are no universally accepted diagnostic criteria for female BOO. In 2018, Solomon et al. proposed the Solomon-Greenwell Nomogram (S-G Nomogram) to diagnose female BOO by the pressure-flow study. The equation of the BOO index in females (BOOIf) is PdetQmax – 2.2*Qmax, similar to the equation of BOOI in men. We aimed to validate the diagnostic value of the S-G Nomogram in female BOO.

Methods:

We retrospectively reviewed the video-urodynamic study (VUDS) cohort in our institution. Between 2015 and 2020, 192 female patients underwent VUDS for lower urinary tract dysfunction (LUTD). All of the VUDS examinations were performed by a single experienced urodynamist. We excluded patients with neurogenic LUTD (n=30) and patients with no detrusor contraction and/or no void during VUDS (n=51). The diagnosis of female BOO was based on the Nitti criteria (radiological evidence of urethral narrowing in the presence of a sustained detrusor pressure). BOOIf was calculated for each enrolled patient. The cut-off value of BOOIf was set as < 0, >5, and >18, as the original S-G nomogram proposed. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of each threshold to diagnose female BOO were calculated.

Results:

Of the 111 enrolled patients, 43 (38.7%) were diagnosed as having female BOO by VUDS. The most common etiology of female BOO was dysfunctional voiding (19/43, 44.2%), followed by primary bladder neck obstruction (PBNO, 15/43, 34.9%). When the cut-off value was set as <0 (low probability of obstruction), the sensitivity, specificity, PPV, NPV were 89.7%, 88.4%, 92.4%, and 84.4%, respectively. When the threshold was >5 (likely obstructed), the values were 79.1%, 95.6%, 91.9%, and 87.8%, respectively. When the threshold was > 18 (obstruction almost certain), the values were 46.5%, 100%, 100%, and 74.7% respectively. Fourteen of 15 PBNO patients would be mis-diagnosed as non-BOO if the cut-off value were set as > 18. Meanwhile, 9 PBNO patients would not be diagnosed as female BOO if the threshold was >5.

Conclusions:

Although BOOIf > 18 has a perfect specificity and PPV to diagnose female BOO, the sensitivity is low. Most PBNO cases would not be classified as female BOO by the S-G nomogram. VUDS is still the examination of choice to diagnose female BOO, especially for PBNO in women.