Kidney Week

Abstract: FR-OR090

Preoperative CT-Based Whole-Kidney Volume Indexed to Body Surface Area Independently Predicts Postdonation CKD in Living Kidney Donors

Session Information

• The Changing Landscape of Kidney Transplantation: Clinical Innovation, Outcomes, and Health Policy
  October 23, 2026 | Location: Mile High Ballroom 4A, Convention Center
  Abstract Time: 05:50 PM - 06:00 PM

Category: Transplantation

• 2002 Transplantation: Clinical

Authors

• Jang, Yoonjoo, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea (the Republic of)

Yoonjoo Jang, MD

• Cho, Yoon Jung, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea (the Republic of)

Yoon Jung Cho, MD

• Gu, Juyeon, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea (the Republic of)

Juyeon Gu, MD

• Jeon, Junseok, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea (the Republic of)

Junseok Jeon, MD, PhD

• Jang, Hye Ryoun, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea (the Republic of)

Hye Ryoun Jang, MD, PhD

• Lee, Kyo Won, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea (the Republic of)

Kyo Won Lee, MD, PhD

• Kang, Kyunga, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea (the Republic of)

Kyunga Kang

• Lee, Kyungho, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea (the Republic of)

Kyungho Lee, MD, PhD

Background

CT-derived kidney volume is routinely measured during living donor evaluation and is conceptually linked to nephron mass, but whether cortical volume (CV) or whole volume (WV) provides better prognostic information remains unclear. Moreover, because kidney size scales with body size, body surface area (BSA)-adjusted volumes may better align structural reserve with physiological demand. We investigated whether CT-based BSA-indexed kidney volumes (CV/BSA, WV/BSA) independently predict post-donation CKD and which index provides stronger prognostic information.

Methods

We retrospectively analyzed 410 living kidney donors who underwent donor nephrectomy between 2016 and 2021. CV and WV of the remnant kidney were measured from preoperative CT, and BSA-adjusted indices were analyzed. CKD was defined as estimated GFR (eGFR) <60 mL/min/1.73 m^2. Logistic regression for 1-year CKD and Cox regression for 5-year CKD were used to assess associations. Model performance was evaluated by AUC, R^2, integrated discrimination improvement (IDI), calibration, decision-curve analysis (DCA), and diagnostic performance of WV/BSA cutoffs.

Results

Baseline eGFR was 111.6±13.7 mL/min/1.73 m^2, with a 1-year CKD incidence of 12.4%. Lower CV, WV, CV/BSA, and WV/BSA were significantly associated with CKD in univariable analyses. In multivariable analysis after adjusting for clinical covariates (age, sex, BMI, diabetes, hypertension, and baseline eGFR), WV/BSA—but not CV/BSA—remained significant for predicting CKD risk at 1 year (OR 0.93, 95% CI 0.89–0.97; P<0.001) and 5 years (HR 0.95, 95% CI 0.93–0.98; P<0.001). Adding WV/BSA to the established clinical model improved discrimination (IDI 0.053, P=0.008; R^2 0.481 vs 0.428), with a non-significant AUC gain (0.941 vs 0.928, P=0.095). Calibration (slope 1.00, Brier 0.060) and DCA showed higher net benefit for the volumetry-enhanced model. Two complementary WV/BSA cutoffs were identified: 92.5 mL/m^2 for initial screening and 85 mL/m^2 for confirmation (false negatives 25.5% vs 41.2%; specificity 0.48 vs 0.78), both yielding NPV 0.93. Notably, in donors with baseline eGFR <90 mL/min/1.73 m^2, the 85 mL/m^2 cutoff achieved a PPV of 0.83.

Conclusion

Preoperative WV/BSA—rather than CV/BSA—independently predicted post-donation CKD at 1 and 5 years and added prognostic value beyond established clinical factors.