Isolated increase in serum alkaline phosphatase after liver transplantation: Risk factors and outcomes analysis

BackgroundIsolated increase in serum alkaline phosphatase (IISAlp) is frequently observed in liver transplant recipients visiting outpatient clinics. However, whether the increase is associated with risk factors or poor survival is unknown.MethodsWe retrospectively reviewed the medical records of liver transplant recipients who were followed up during 1999–2009 and had IISAlp 1 month after liver transplantation, which was sustained for at least 6 months. Clinical parameters, survival, and risk factors were analyzed and compared between recipients who survived longer than 6 months after transplantation.ResultsAmong 307 liver transplant recipients, 44 had IISAlp. Compared with the control group, the patients with IISAlp were more frequently of the pediatric population, recipients of female donor or living-related partial liver grafts, and found to have biliary-related pretransplant disorders, lower body weight, and shorter warm ischemic time (P < 0.01). One patient with IISAlp died of acute myeloid leukemia during the follow-up period. The mean time to observation of IISAlp after liver transplantation was 6.3 ± 0.8 months. The mean follow-up duration was 5.5 ± 0.2 years. Stepwise multivariate analysis showed that being a pediatric or living-related liver transplant recipient was an independent risk factor for IISAlp, with adjusted hazard ratios (95% confidence interval) of 5.41 (2.59–11.28) and 3.0 (0.98–9.27), respectively.ConclusionsTherefore, being a pediatric or living-related liver transplant recipient was an independent risk factor for IISAlp. However, IISAlp was not associated with poor survival after liver transplantation. Hence, patients who have undergone liver transplantation do not require frequent routine examination of serum alkaline phosphatase levels.