Anemia Is Associated with Mortality in Kidney-Transplanted Patients
Anemia Is Associated with Mortality in Kidney-Transplanted Patients
Although anemia is a known risk factor of mortality in several patient populations, no prospective study to date has demonstrated association between anemia and mortality in kidney-transplanted patients. In our prospective cohort study (TransQol-HU Study), we tested the hypothesis that anemia is associated with mortality and graft failure (return to dialysis) in transplanted patients. Data from 938 transplanted patients, followed at a single outpatient transplant center, were analyzed. Sociodemographic parameters, laboratory data, medical history and information on comorbidity were collected at baseline. Data on 4-year outcome (graft failure, mortality or combination of both) were collected prospectively from the patients' charts. Both mortality and graft failure rate during the 4-year follow-up was significantly higher in patients who were anemic at baseline (for anemic vs nonanemic patients, respectively: mortality 18% vs. 10%; p < 0.001; graft failure 17% vs 6%; p < 0.001). In multivariate Cox proportional hazard models the presence of anemia significantly predicted mortality (HR = 1.690; 95% CI: 1.115-2.560) and also graft failure (HR = 2.465; 95% CI: 1.485-4.090) after adjustment for several covariables. Anemia, which is a treatable complication, is significantly and independently associated with mortality and graft failure in kidney-transplanted patients.
The pathogenesis of posttransplant anemia (PTA) is multifactorial, but declining renal function and failing erythropoietin synthesis plays an important role. Although the reported prevalence of PTA shows great variations in different studies, the three recent surveys enrolling the largest number of patients reported a more consistent prevalence of 30-40%. Severe anemia, requiring treatment based on current guidelines, is less frequent with an estimated prevalence of about 10-15%.
Recent studies have demonstrated an association between lower hemoglobin levels and mortality both in dialysis and in chronic kidney disease (CKD) patients not yet on dialysis. However, conflicting results have been published on the association between anemia and outcome in kidney-transplanted patients. In a prospective study, Winkelmayer at al. found no significant association between anemia or serum hemoglobin level versus outcome (mortality or graft failure). On the other hand, in a retrospective analysis, Heinze et al. suggested that anemia may be associated with mortality in the kidney-transplanted patients.
Similar to dialyzed patients, cardiovascular diseases are the leading cause of death in the kidney-transplanted population. Anemia is associated with early post-transplant cardiovascular risk in diabetic patients. Furthermore, the presence of anemia is an independent predictor of both left ventricular hypertrophy and congestive heart failure in transplanted patients. It has also been reported that both left ventricular hypertrophy and congestive heart failure were independent predictors of mortality in this population. It is, therefore, conceivable that the presence of anemia is a predictor of negative outcome in transplanted patients.
In addition to potentially leading to cardiovascular disease, anemia may also contribute to more rapid loss of renal function in patients with impaired renal function. A recent study suggested that anemia significantly predicted the decline of renal function among CKD patients and also among heart-transplant recipients. Furthermore, Gouva et al. have recently shown that treating anemia in CKD patients can slow the decline of renal function.
On the basis of the above information, we hypothesized that PTA is associated with negative outcome, i.e. with mortality and graft failure (return to dialysis) in kidney-transplanted patients. To test this hypothesis, a prospective cohort study was designed. More than 900 kidney-transplanted patients were followed at a single transplant clinic for about 46 months and data on outcome were collected prospectively. Our results revealed that the presence of anemia is independently and significantly associated with both mortality and graft failure in kidney-transplanted patients.
Abstract and Introduction
Abstract
Although anemia is a known risk factor of mortality in several patient populations, no prospective study to date has demonstrated association between anemia and mortality in kidney-transplanted patients. In our prospective cohort study (TransQol-HU Study), we tested the hypothesis that anemia is associated with mortality and graft failure (return to dialysis) in transplanted patients. Data from 938 transplanted patients, followed at a single outpatient transplant center, were analyzed. Sociodemographic parameters, laboratory data, medical history and information on comorbidity were collected at baseline. Data on 4-year outcome (graft failure, mortality or combination of both) were collected prospectively from the patients' charts. Both mortality and graft failure rate during the 4-year follow-up was significantly higher in patients who were anemic at baseline (for anemic vs nonanemic patients, respectively: mortality 18% vs. 10%; p < 0.001; graft failure 17% vs 6%; p < 0.001). In multivariate Cox proportional hazard models the presence of anemia significantly predicted mortality (HR = 1.690; 95% CI: 1.115-2.560) and also graft failure (HR = 2.465; 95% CI: 1.485-4.090) after adjustment for several covariables. Anemia, which is a treatable complication, is significantly and independently associated with mortality and graft failure in kidney-transplanted patients.
Introduction
The pathogenesis of posttransplant anemia (PTA) is multifactorial, but declining renal function and failing erythropoietin synthesis plays an important role. Although the reported prevalence of PTA shows great variations in different studies, the three recent surveys enrolling the largest number of patients reported a more consistent prevalence of 30-40%. Severe anemia, requiring treatment based on current guidelines, is less frequent with an estimated prevalence of about 10-15%.
Recent studies have demonstrated an association between lower hemoglobin levels and mortality both in dialysis and in chronic kidney disease (CKD) patients not yet on dialysis. However, conflicting results have been published on the association between anemia and outcome in kidney-transplanted patients. In a prospective study, Winkelmayer at al. found no significant association between anemia or serum hemoglobin level versus outcome (mortality or graft failure). On the other hand, in a retrospective analysis, Heinze et al. suggested that anemia may be associated with mortality in the kidney-transplanted patients.
Similar to dialyzed patients, cardiovascular diseases are the leading cause of death in the kidney-transplanted population. Anemia is associated with early post-transplant cardiovascular risk in diabetic patients. Furthermore, the presence of anemia is an independent predictor of both left ventricular hypertrophy and congestive heart failure in transplanted patients. It has also been reported that both left ventricular hypertrophy and congestive heart failure were independent predictors of mortality in this population. It is, therefore, conceivable that the presence of anemia is a predictor of negative outcome in transplanted patients.
In addition to potentially leading to cardiovascular disease, anemia may also contribute to more rapid loss of renal function in patients with impaired renal function. A recent study suggested that anemia significantly predicted the decline of renal function among CKD patients and also among heart-transplant recipients. Furthermore, Gouva et al. have recently shown that treating anemia in CKD patients can slow the decline of renal function.
On the basis of the above information, we hypothesized that PTA is associated with negative outcome, i.e. with mortality and graft failure (return to dialysis) in kidney-transplanted patients. To test this hypothesis, a prospective cohort study was designed. More than 900 kidney-transplanted patients were followed at a single transplant clinic for about 46 months and data on outcome were collected prospectively. Our results revealed that the presence of anemia is independently and significantly associated with both mortality and graft failure in kidney-transplanted patients.
Source...