Category: Laparoscopic/ Robotic: Other

MP16-10 - External validation of a preoperative nomogram for predicting renal function at 1 year after partial nephrectomy in an Asian population

Sat, Sep 22
10:00 AM - 12:00 PM

Introduction & Objective :

Partial nephrectomy (PN) decreases the risk of post-operative chronic renal insufficiency (CRI) compared to radical nephrectomy. Nevertheless, a proportion of patients still progress to CRI after PN, necessitating renal replacement therapy. A tool to predict post-PN estimated glomerular filtration rates (eGFRs) would be helpful in counseling patients pre-operatively. Recently, Shum et al published a nomogram in 2017 predicting eGFRs 1 year after PN in an American population.(1) We sought to externally validate this nomogram in our Asian population.


Methods :

We identified patients who underwent PN at our institution between 2005 to 2014, with known post-operative serum creatinine levels at 1 year.  The pre-operative covariates were the same as those used in the paper published by Shum et al (2017)(1) . The endpoint was eGFRs at 1 year after PN, calculated using the modification of diet in renal disease (MDRD) formula, compared against the predicted eGFR 1 year after PN using the nomogram. The area under the curve (AUC) for the receiver operating characteristic (ROC) curve of the nomogram was calculated.


Results :

53 patients were suitable for analysis. 58% (n= 31) of them were male, while 42% (n=22) were female. The average body mass index (BMI) was 25.7 (± 4.9). The average pre-operative eGFR was 85.0 (± 30.6) while the average 1 year post-PN eGFR was 70.9 (± 25.6). The average age of our patients was 59.5 (± 10.6). The percentage of patients with eGFR below 60mL/min/1.73m2 increased from 20% before PN to 30% 1 year post-PN. External validation of the nomogram by Shum et al. (2017) showed an AUC of 0.81.  Of note, overestimation of predicted eGFRs 1 year post-PN was more apparent in the chronic kidney disease population.


Conclusions :

We have externally validated a nomogram using only preoperative covariates to predict renal function at 1 year after PN. This nomogram can serve as a valuable guide in managing and counseling our local patients considering PN.



References


1. Shum CF, Bahler CD, Cary C et al. Preoperative Nomograms for Predicting Renal Function at 1 Year After Partial Nephrectomy. J Endourol. 2017 Jul;31(7):711-718.doi:10.1089/end.2017.0184.

Marcus Way Lunn Chow

Resident
Tan Tock Seng Hospital
Singapore, Not Applicable, Singapore

Dr Marcus Chow
MBChB (Edin), MRCS (Edin)
Resident
Tan Tock Seng Hospital

Daniel Zhan Peng Yong

Senior resident
Mohh
Singapore, Not Applicable, Singapore

Jia Lun Kwok

Singapore, Not Applicable, Singapore

Cheuk Fan Shum

Consultant
Khoo Teck Puat Hospital
Singapore, Not Applicable, Singapore

MBBS, MRCSEd, MMed (Surgery), FAMS (Urology)

Consultant, Department of Urology, Khoo Teck Puat Hospital, Singapore

Keng Siang Png

Senior Consultant
Department of Urology, Tan Tock Seng Hospital (Singapore)
Singapore, Not Applicable, Singapore