Incidence and Impact of Elevated Creatine Kinase Following Living Donor Nephrectomy

The clinical significance of elevated creatine kinase (CK) levels following living kidney donation (LKD) remains poorly characterized.

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.

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.

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.