Incidence and Impact of Elevated Creatine Kinase Following Living Donor Nephrectomy

Background: The clinical significance of elevated creatine kinase (CK) levels following living kidney donation (LKD) remains poorly characterized. Methods: In this single-center retrospective study, we analyzed 264 consecutive donors undergoing hand-assisted laparoscopic donor nephrectomy (HALDN) between March 2021 and December 2023. CK levels were monitored postoperatively on days 0 (POD0) and 1 (POD1), with POD2 testing performed only if clinically indicated. Primary outcomes included serum creatinine and estimated glomerular filtration rate (eGFR) at six months post donation. Results: The cohort comprised 65.9% female and 90.2% Caucasian donors, with a median age of 42.7 years (IQR 18.8) and BMI of 26.4 (IQR 5.0). Median CK levels rose from 109 U/L (IQR 64.5) on POD0 to 406 U/L (IQR 375) on POD1, peaking at 1845 U/L (IQR 3724) on POD2. Clinically significant CK elevations (>1000 U/L) occurred in 8.7% (n = 23) of donors, with 2.3% (n = 6) exceeding 5000 U/L. Presumed myoglobinuria developed in two donors (both with CK >5000 U/L). Risk factors for CK >1000 U/L included male sex (65% vs. 31%; P =. 002) and higher pre-donation creatinine (0.88 vs. 0.80 mg/dL; P =. 005). For CK >5000 U/L, male sex (83% vs. 33%; P =. 01) and longer operative time (3.9 vs. 3.3 hours; P =. 0008) were predictive. At six months, elevated CK showed no correlation with reduced eGFR (P >. 05). All donors with CK >5000 U/L recovered fully with supportive care. Conclusions: While elevated CK levels are common after HLDN, progression to clinically significant rhabdomyolysis is rare when identified and treated (2.3%). Male sex, higher baseline creatinine, and prolonged operative time identify at-risk donors. Routine CK monitoring enables early detection of subclinical rhabdomyolysis, though transient elevations do not impact intermediate-term renal function.