Pharmacoepidemiology of anemia in kidney transplant recipients

ABSTRACT. Anemia has long been known to be a complication of end-stage renal disease (ESRD), and it has been linked to cardiovascular morbidity and mortality. Although kidney transplant recipients (KTR) are prone to experiencing cardiovascular outcomes, little is known about the epidemiology of anemia in this population. With few exceptions, studies to date have not fully evaluated the associations between posttransplant anemia (PTA) and medications commonly used in KTR, particularly immunosuppressant drugs, angiotensin-converting enzyme inhibitors (ACEI) and angiotensin II receptor blockers (ARB). The authors aimed to specifically investigate possible associations between these drugs and PTA. Detailed medical information was retrospectively collected on 374 consecutive KTR from our transplant clinic. Univariate/multivariate linear regression models were used to test for associations between hematocrit (HCT) and other covariates, and logistic regression models were used to detect independent predictors of PTA, defined as HCT <33%. The mean time since transplantation was 7.7 yr, and mean creatinine was 2.2 mg/dl. The prevalence of PTA was 28.6%. Ten percent of all patients were on erythropoietin therapy, but only 41.6% of patients whose HCT was <30 received this treatment. From multivariate analyses, the authors found that female gender and lower renal function were associated with lower HCT (both P < 0.001). Patients on ACEI had significantly lower HCT (P = 0.005) compared with patients without such treatment. In addition, a significant curvilinear dose-response relationship was found between ACEI dose and HCT. Among the immunosuppressant drugs, mycophenolate mofetil (P = 0.05) and tacrolimus (P = 0.02) were associated with a lower HCT. The authors conclude that PTA is prevalent and undertreated in KTR. Several medications that are possibly modifiable correlates of PTR deserve further study.