Validation of cardiovascular risk scores in a liver transplant population

Increased prevalence of cardiovascular risk factors has been acknowledged in liver transplant recipients, and an increased incidence of cardiovascular events has been suspected. Individual risk determination, however, has not yet been established. Outpatient charts of 438 primary liver transplants have been reviewed, and suspected cardiovascular risk factors were correlated with cardiovascular events observed during a follow-up period of 10 yr. Receiver operation characteristics curve (ROC) analysis was performed to validate established cardiovascular risk scores. For calibration, the Hosmer-Lemeshow test was performed. A total of 303 of 438 patients were available for risk factor analysis at 6 months and demonstrated complete follow-up data (175 male, 128 female). A total of 40 of those 303 patients experienced fatal or nonfatal cardiovascular events (13.2%). In univariate analysis, age (P < 0.001), gender (P = 0.002), body mass index (P = 0.018), cholesterol (P = 0.044), creatinine (P = 0.006), diabetes mellitus (P = 0.017), glucose (0.006), and systolic blood pressure (P = 0.043), but not cyclosporine A (P = 0.743), tacrolimus (P = 0.870), or steroid medication (P = 0.991), were significantly associated with cardiovascular events. Multivariate analysis, however, identified only age, gender, and cholesterol as independent predictors. In ROC analysis, corresponding areas under the curve for Systematic Coronary Risk Evaluation Project (SCORE), Prospective Cardiovascular Winster Study (PROCAM), and Framingham risk scores (FRSs) were calculated with 0.800, 0.778, and 0.707, respectively. Calibration demonstrated an improved goodness of fit for PROCAM compared to SCORE risk calculations. In conclusion, SCORE and PROCAM proved to be valuable in discriminating our liver transplant recipients for their individual risk of cardiovascular events. Furthermore, calibrated PROCAM risk estimates are required to calculate the number of patients needed to treat in the setup of prospective intervention trials.