Hyperlipidemia After Allogeneic Stem Cell Transplantation: Prevalence, Risk Factors and Impact on Prognosis.

Hyperlipidemia is one of the late complications after allogeneic stem cell transplantation (SCT). Although intrahepatic cholestasis caused by chronic graft-versus host disease (GVHD) or calcineurin inhibitors has been considered to be one of the etiologies, its prevalence, risk factors, and the impact on prognosis have not been investigated well.

We performed a retrospective analysis of 194 adult patients who underwent allogeneic SCT between 1995 and 2008 in our institute, and survived more than 100 days after SCT. Hypercholesterolemia or hypertriglyceridemia was defined as more than 240 mg/dl or 200 mg/dl, respectively, at two successive tests at least one week apart after the first 100 days after SCT. Cumulative incidence of hypercholesterolemia or hypertriglyceridemia was analyzed. The time to the development of hypercholesterolemia or hypertriglyceridemia was calculated and the multivariate analysis of pre- and posttransplant variables was performed by a Cox proportional hazards model. Chonic GVHD, chronic liver dysfunction (CLD; defined as more than twice the upper limit of normal for aspartate aminotransferase, alanine aminotransferase, or alkaline phosphatase, or total bilirubin >3 mg/dl over 3 months) and administration of calcineurin inhibitors were studied as posttransplant factors, which were assessed as time-dependent variables. To analyze the prognosis of patients who developed persistent hyperlipidemia, the multivariate analysis of overall survival (OS), relapse rate, and non-relapse mortality (NRM) was carried out by a landmark approach. Persistent hyperlipidemia was defined as hypercholesterolemia or hypertriglyceridemia continuing more than 3 months.

Overall, 83 (42.8%) and 98 (50.5%) patients developed hypercholesterolemia and hypertriglyceridemia, respectively. The median follow-up period of serum cholesterol and triglyceride values in surviving patients was 44 months. The cumulative incidence of each abnormality at 3 years after SCT was 38.1% (95% confidence interval [CI]: 31.0–45.1%), and 46.0% (95% CI: 38.8–52.9%), respectively. In a multivariate analysis, the development of chronic GVHD was independently associated with both hypercholesterolemia (hazard ratio [HR] 2.05, 95% CI: 1.23–3.43, P<0.01) and hypertriglyceridemia (HR 2.04, 95% CI: 1.30–3.18, P<0.01). Besides, CLD was significantly associated with hypercholesterolemia (HR 2.20, 95% CI: 1.39–2.50, P<0.01). Administration of calcineurin inhibitors was not an independent risk factor for the development of hypercholesterolemia (HR 1.23, 95% CI: 0.73–2.08, P=0.43) or hypertriglyceridemia (HR 1.03, 95% CI: 0.61–1.54, P=0.89). Among pretransplant factors, prior hypercholesterolemia and hypertriglyceridemia were associated with posttransplant hypercholesterolemia (HR 2.76, 95% CI: 1.07–7.17, P=0.04) and hypertriglyceridemia (HR 2.04, 95% CI: 1.27–3.27, P<0.01), respectively. Persistent hyperlipidemia was found in 49 patients (25.3%), of which 35 patients (71.4%) developed hyperlipidemia within one year. The median interval to the occurrence of hyperlipidemia of the patients was 180 days after SCT. In univariate analysis, patients with persistent hyperlipidemia had a tendency of better 3-year OS (77.3% vs 64.7%, P=0.23). Multivariate analysis showed that the development of persistent hyperlipidemia was independently associated with better OS (HR: 0.49, P=0.049). Further, although not statistically significant, patients with persistent hyperlipidemia had a tendency of lower 3-year cumulative relapse rate (15.7% vs 20.3%). There were no significant differences in 3-year NRM between patients with or without hyperlipidemia (12.3% vs 13.9%).

Both hypercholesterolemia and hypertriglyceridemia are very common complications after SCT. Patients with persistent hyperlipidemia, however, have significantly better OS. Considering a strong association between the development of hyperlipidemia and chronic GVHD, and a tendency of lower relapse rate in patients with persistent hyperlipidemia, hyperlipidemia is regarded as one of the symptoms accompanied with chronic GVHD. Unless severe, its incidence indicates a better control of the primary disease and an improved prognosis.

No relevant conflicts of interest to declare.