Hemoglobin A(1c) levels and mortality in the diabetic hemodialysis population: findings from the Dialysis Outcomes and Practice Patterns Study (DOPPS)

OBJECTIVE

Lowering hemoglobin A(1c) to <7% reduces the risk of microvascular complications of diabetes, but the importance of maintaining this target in diabetes patients with kidney failure is unclear. We evaluated the relationship between A(1c) levels and mortality in an international prospective cohort study of hemodialysis patients.

RESEARCH DESIGN AND METHODS

Included were 9,201 hemodialysis patients from 12 countries (Dialysis Outcomes and Practice Patterns Study 3 and 4, 2006-2010) with type 1 or type 2 diabetes and at least one A(1c) measurement during the first 8 months after study entry. Associations between A(1c) and mortality were assessed with Cox regression, adjusting for potential confounders.

RESULTS

The association between A(1c) and mortality was U-shaped. Compared with an A(1c) of 7-7.9%, the hazard ratios (95% CI) for A(1c) levels were 1.35 (1.09-1.67) for <5%, 1.18 (1.01-1.37) for 5-5.9%, 1.21 (1.05-1.41) for 6-6.9%, 1.16 (0.94-1.43) for 8-8.9%, and 1.38 (1.11-1.71) for ≥9.0%, after adjustment for age, sex, race, BMI, serum albumin, years of dialysis, serum creatinine, 12 comorbid conditions, insulin use, hemoglobin, LDL cholesterol, country, and study phase. Diabetes medications were prescribed for 35% of patients with A(1c) <6% and not prescribed for 29% of those with A(1c) ≥9%.

CONCLUSIONS

A(1c) levels strongly predicted mortality in hemodialysis patients with type 1 or type 2 diabetes. Mortality increased as A(1c) moved further from 7-7.9%; thus, target A(1c) in hemodialysis patients may encompass values higher than those recommended by current guidelines. Modifying glucose-lowering medicines for dialysis patients to target A(1c) levels within this range may be a modifiable practice to improve outcomes.

Predictors of liver donation without kidney recovery in a cohort of expanded criteria donors: identifying opportunities to improve expanded criteria donor kidney utilization

To maximize deceased donation, it is necessary to facilitate organ recovery from expanded criteria donors (ECDs). Utilization of donors meeting the kidney definition for ECDs increases access to kidney transplantation and reduces waiting times; however, ECDs often do not proceed to kidney recovery. Based on a prospective study of three Organ Procurement Organizations in the United States, we describe the characteristics of donors meeting the Organ Procurement and Transplant Network (OPTN) ECD kidney definition (donor age 60+ or donor age 50-60 years with two of the following: final serum creatinine > 1.5 mg/dL, history of hypertension, or death from cerebral vascular accident) who donated a liver without kidney recovery. ECDs with organs recovered between February 2003 and September 2005 by New England Organ Bank, Gift of Life Michigan, and LifeChoice Donor Services were studied (n = 324). All donors were declared dead by neurological criteria. Data on a wide range of donor characteristics were collected, including donor demographics, medical history, cause of death, donor status during hospitalization, serological status, and donor kidney quality. Logistic regression models were used to identify donor characteristics predictive of liver-alone donation. Seventy-four of the 324 donors fulfilling the ECD definition for kidneys donated a liver alone (23%). History of diabetes, final serum creatinine > 1.5 mg/dL, age 70+, and presence of proteinuria were associated with liver-alone donation in univariate models. On multivariate analysis, only final serum creatinine > 1.5 mg/dL and age 70+ were independently predictive of liver donation alone. Older age and elevated serum creatinine may be perceived as stronger contraindications to kidney donation than the remaining elements of the ECD definition. It is likely that at least a proportion of these liver-alone donors represent missed opportunities for kidney transplantation.

Transplanting kidneys without points for HLA-B matching: consequences of the policy change

In 2003, the US kidney allocation system was changed to eliminate priority for HLA-B similarity. We report outcomes from before and after this change using data from the Scientific Registry of Transplant Recipients (SRTR). Analyses were based on 108 701 solitary deceased donor kidney recipients during the 6 years before and after the policy change. Racial/ethnic distributions of recipients in the two periods were compared (chi-square); graft failures were analyzed using Cox models. In the 6 years before and after the policy change, the overall number of deceased donor transplants rose 23%, with a larger increase for minorities (40%) and a smaller increase for non-Hispanic whites (whites) (8%). The increase in the proportion of transplants for non-whites versus whites was highly significant (p < 0.0001). Two-year graft survival improved for all racial/ethnic groups after implementation of this new policy. Findings confirmed prior SRTR predictions. Following elimination of allocation priority for HLA-B similarity, the deficit in transplantation rates among minorities compared with that for whites was reduced but not eliminated; furthermore, there was no adverse effect on graft survival.

Transplants in Foreign Countries Among Patients Removed from the US Transplant Waiting List

Transplant tourism, where patients travel to foreign countries specifically to receive a transplant, is poorly characterized. This study examined national data to determine the minimum scope of this practice. US national waiting list removal data were analyzed. Waiting list removals for transplant without a corresponding US transplant in the database were reviewed via a data validation query to transplant centers to identify foreign transplants. Additionally, waiting list removal records with text field entries indicating a transplant abroad were identified. We identified 373 foreign transplants (173 directly noted; 200 from data validation); most (89.3%) were kidney transplants. Between 2001 and 2006, the annual number of waiting list removals for transplant abroad increased. Male sex, Asian race, resident and nonresident alien status and college education were significantly and independently associated with foreign transplant. Recipients from 34 states, plus the District of Columbia, received foreign transplants in 35 countries, led by China, the Philippines and India. Transplants in foreign countries among waitlisted candidates in the US are increasingly performed. The data reported here represent the minimum number of cases and the full extent of this practice cannot be determined using existing data. Additional reporting requirements are needed.

Determinants of discard of expanded criteria donor kidneys: impact of biopsy and machine perfusion

We examined factors associated with expanded criteria donor (ECD) kidney discard. Scientific Registry of Transplant Recipients (SRTR)/Organ Procurement and Transplantation Network (OPTN) data were examined for donor factors using logistic regression to determine the adjusted odds ratio (AOR) of discard of kidneys recovered between October 1999 and June 2005. Logistic and Cox regression models were used to determine associations with delayed graft function (DGF) and graft failure. Of the 12,536 recovered ECD kidneys, 5139 (41%) were discarded. Both the performance of a biopsy (AOR = 1.21, p = 0.02) and the degree of glomerulosclerosis (GS) on biopsy were significantly associated with increased odds of discard. GS was not consistently associated with DGF or graft failure. The discard rate of pumped ECD kidneys was 29.7% versus 43.6% for unpumped (AOR = 0.52, p < 0.0001). Among pumped kidneys, those with resistances of 0.26-0.38 and >0.38 mmHg/mL/min were discarded more than those with resistances of 0.18-0.25 mmHg/mL/min (AOR = 2.5 and 7.9, respectively). Among ECD kidneys, pumped kidneys were less likely to have DGF (AOR = 0.59, p < 0.0001) but not graft failure (RR = 0.9, p = 0.27). Biopsy findings and machine perfusion are important correlates of ECD kidney discard; corresponding associations with graft failure require further study.

Diabetes, glycaemic control and mortality risk in patients on haemodialysis: the Japan Dialysis Outcomes and Practice Pattern Study

AIMS/HYPOTHESIS

There are few data on the target level of glycaemic control among patients with diabetes on haemodialysis. We investigated the impact of glycaemic control on mortality risk among diabetic patients on haemodialysis.

SUBJECTS AND METHODS

Data were analysed from the Dialysis Outcomes Practice Pattern Study (DOPPS) for randomly selected patients on haemodialysis in Japan. The diagnosis of diabetes at baseline and information on clinical events during follow-up were abstracted from the medical records. A Cox proportional hazards model was used to evaluate the association between presence or absence of diabetes, glycaemic control (HbA(1c) quintiles) and mortality risk.

RESULTS

Data from 1,569 patients with and 3,342 patients without diabetes on haemodialysis were analysed. Among patients on haemodialysis, those with diabetes had a higher mortality risk than those without (multivariable hazard ratio 1.37, 95% CI 1.08-1.74). Compared with those in the bottom quintile of HbA(1c) level, the multivariable-adjusted hazard ratio for mortality was not increased in the bottom second to fourth quintiles of HbA(1c) (HbA(1c) 5.0-5.5% to 6.2-7.2%), but was significantly increased to 2.36 (95% CI 1.02-5.47) in the fifth quintile (HbA(1c) > or = 7.3%). The effect of poor glycaemic control did not statistically correlate with baseline mortality risk (p = 0.27).

CONCLUSIONS/INTERPRETATION

Among dialysis patients, poorer glycaemic control in those with diabetes was associated with higher mortality risk. This suggests a strong effect of poor glycaemic control above an HbA(1c) level of about 7.3% on mortality risk, and that this effect does not appear to be influenced by baseline comorbidity status.

Mortality experience in recipients undergoing repeat transplantation with expanded criteria donor and non-ECD deceased-donor kidneys

Nearly one-quarter of the kidney transplant waiting list is composed of repeat transplantation candidates. Survival following retransplantation using expanded criteria donor (ECD) kidneys has not been adequately studied. Using data from the Scientific Registry of Transplant Recipients, we analyzed mortality after retransplantation with ECD and non-ECD deceased-donor kidneys. Adult patients who experienced graft failure and were relisted for transplantation between 1995 and 2004 were studied (n=9641). Follow-up began at the date of relisting and continued until death or the end of the observation period (December 31, 2004), with censoring at living-donor transplantation. Sequential stratification (an extension of Cox regression) was used to compare mortality between patients receiving an ECD retransplant and those remaining on the waiting list or receiving a non-ECD retransplant (conventional therapy). Of 2908 retransplantations, 292 used ECD kidneys. Survival after ECD retransplantation was approximately equal to that of conventional therapy, with an adjusted hazard ratio of 0.98 (p=0.88). In contrast, non-ECD retransplant recipients experienced a significant reduction in mortality (HR=0.44; p<0.0001). Based on these national data, recipients of ECD retransplantation do not have a survival advantage relative to conventional therapy, whereas non-ECD retransplantation is associated with a significant survival advantage.

[DOPPS estimate of guideline impact on survival in hemodialysis in Italy]

Knowing the relative risk (RR) of mortality associated with being outside the guideline targets and the percentage of patients in this situation, it is possible to estimate the number of patient life years that could be gained from adhering to guideline recommendations. We used a prevalent cross-sectional sample of 576 Italian patients from the Dialysis Outcomes and Practices Patterns Study (DOPPS) phase II (2002-2004) to determine the percentage of patients who failed to meet the Italian Society of Nephrology's targets for dialysis dose (spKt/V ≥ 1.3), anemia management (hemoglobin ≥ 11 g/dL), and mineral metabolism (serum calcium and phosphorus: ≤ 2.6 and ≤ 1.8 mmol/L, respectively), and the National Kidney Foundation's Kidney Disease Outcomes Quality Initiative (K/DOQI) targets for nutritional status (serum albumin ≥ 4 g/dL) and vascular access (facility catheter use ≤ 10%). We used a larger random sample of DOPPS patients to establish the adjusted RRs of mortality associated with the 6 examined targets. The percentage of patients outside the targets and the adjusted RRs were 34% and 1.12 for dialysis dose, 37.7% and 1.20 for anemia management, 40.8% and 1.14 for phosphorus, 14.4% and 1.22 for calcium, 62.5% and 1.46 for albumin, and 40.1% and 1.20 for facility catheter use. The adjusted sum of life years potentially gained by complete adherence to all 6 guidelines was 25,156 over a period of 5 years (2006-2010); a more conservative estimate, modeling life years potentially gained by bringing half of all patients outside targets within them, was 13,382. In conclusion, this analysis suggests opportunities to improve hemodialysis patient care in Italy. The magnitude of potential savings in life years should encourage greater adherence to guidelines and practices that are significantly associated with better survival.

Geographic variability in access to primary kidney transplantation in the United States, 1996-2005

This article focuses on geographic variability in patient access to kidney transplantation in the United States. It examines geographic differences and trends in access rates to kidney transplantation, in the component rates of wait-listing, and of living and deceased donor transplantation. Using data from Centers for Medicare and Medicaid Services and the Organ Procurement and Transplantation Network/Scientific Registry of Transplant Recipients, we studied 700,000+ patients under 75, who began chronic dialysis treatment, received their first living donor kidney transplant, or were placed on the waiting list pre-emptively. Relative rates of wait-listing and transplantation by State were calculated using Cox regression models, adjusted for patient demographics. There were geographic differences in access to the kidney waiting list and to a kidney transplant. Adjusted wait-list rates ranged from 37% lower to 64% higher than the national average. The living donor rate ranged from 57% lower to 166% higher, while the deceased donor transplant rate ranged from 60% lower to 150% higher than the national average. In general, States with higher wait-listing rates tended to have lower transplantation rates and States with lower wait-listing rates had higher transplant rates. Six States demonstrated both high wait-listing and deceased donor transplantation rates while six others, plus D.C. and Puerto Rico, were below the national average for both parameters.

DOPPS estimate of patient life years attributable to modifiable hemodialysis practices in Canada

We examined data from the Canadian Organ Replacement Registry, and from a special substudy of CORR, to determine whether changes have occurred in practice patterns before and after the 1999 Canadian Society of Nephrology guidelines were published. Second, we used data from the Dialysis Outcomes and Practice Patterns Study to calculate the impact of observed deviations from guideline targets and estimated potential gains in life years that might accrue if guideline targets were achieved in all Canadian hemodialysis patients. For dialysis dose and hemoglobin targets, there was a significant improvement in Canadian facility performance over time. On the other hand, vascular access care showed a worse pattern with increased catheter use. A calculation of attributable risk, which assumes causality, suggests that 49 percent of deaths could be averted if all patients currently outside the guidelines achieved them over the next five years. When expressed as an annual death rate per hundred patient years, this corresponds to a decrease from 18 to 10.1 deaths per 100 patient years. We conclude that promoting a facility-based culture of quality improvement based on achievement of guideline targets is supported by international and Canadian observational data from the DOPPS. In the future, the impact of such an approach should be assessed empirically by correlating changes in practice over time with changes in outcomes.

Optimizing hemodialysis practices in Canada could improve patient survival

Data from the Canadian Organ Replacement Registry (CORR) and the Dialysis Outcomes and Practice Patterns Study (DOPPS) were used to determine whether practice patterns have changed in Canada since the introduction of the Canadian Society of Nephrology (CSN) Guidelines in 1999. DOPPS data were then used to calculate the impact of not meeting the proposed guideline targets and to estimate the potential life years gained if all Canadian hemodialysis patients achieved guideline targets. For dialysis dose and hemoglobin targets, Canadian facility performance has significantly improved over time. The vascular access use patterns show trends toward a worse pattern with increased catheter use. A calculation of the percentage of attributable risk suggests that 49% of deaths could possibly be averted if all patients currently outside the guidelines achieved them over the next five years. This corresponds to a decrease in the annual death rate from 18 to 10.1 per hundred patient years. These data support the need for improved adherence to guidelines. If Canadian caregivers were to optimize practice patterns, patient outcomes could be improved.

Dopps estimate of patient life years attributable to modifiable haemodialysis practices in Belgium

BACKGROUND

Various organizations have published clinical practice guidelines for the care of haemodialysis patients. However, it is unknown to what extent improving or even reaching perfect compliance with guidelines would improve the survival of HD patients in Belgium.

METHODS

Using data from the second phase of the Dialysis Outcomes and Practice Patterns Study (DOPPS), the proportion of haemodialysis patients failing to meet six key practice targets (Kt/V > or = 1.2, haemoglobin > or =11 g/dl, phosphate 1.1-1.5 mmol/l, calcium 2.1-2, 4 mmol/l, albumin > or =40 g/l, and facility catheter use < or =10%) was calculated along with the relative risk of mortality associated with being outside these targets. The life years potentially gained from adherence to the six targets, both separately and all six together were then estimated.

RESULTS

The percentage of patients outside the targets were as follows: 30.3%, Kt/V; 33.6%, haemoglobin; 56.2%, phosphate; 58.2%, calcium; 67.1%, albumin; and 91.1%, catheter. Estimated patient life years gained with improved compliance with guidelines was highest for albumin (3.670) and catheter use (2.331) but still substantial for the other four targets (ranging from 551 to 1.258). The total of patient years gained if 100% of patients have all six practices brought within target reaches 7.516 years. A conservative estimate of 50% of patients within all targets still yields an improvement of survival of 3.958 patient years.

CONCLUSION

This analysis suggests large opportunities to improve HD patient care in Belgium. The avoidance of HD catheters, with the use of AV fistulas whenever possible, should be given a high priority. Admittedly, these calculations assume causality or partial causality that has not been definitively proven. Still, if causality is only partial, the results emphasize that the improvement of patient care through adherence to targets of clinical guidelines might be substantial and all Belgian nephrologists and staff members of dialysis units should carefully pursue every potential effort.

[DOPPS estimate of patient life years attributable to modifiable hemodialysis practices in Spain]

The increased mortality risk in hemodialysis (HD) patients unable to meet six targets in different areas of HD practice has been reported previously. Using a prevalent cross-sectional sample of Spanish HD patients (n = 613) from the second stage of the Dialysis Outcomes and Practice Patterns Study to determine the percentage with low dialysis dose, hyperphosphatemia, hypercalcemia, hypoalbuminemia, anemia, and catheter use and based on the mortality hazard ratios and the total HD population in Spain, according to the Spanish Society of Nephrology Report, we estimated the number of patient life years that could potentially be gained in our country. These characteristics of HD practice were selected because each is modifiable through changes in practice, each is associated with mortality, and each has a large number of patients outside the target guidelines. The targets that define "within guidelines" are as follows: dialysis dose (single pool Kt/V >1.2), anemia (hemoglobin >110 g/L), albumin after standardization (>40 g/L), serum phosphorus (1.1-1.5 mmol/L), serum calcium (2.1-2.4 mmol/L), and facility catheter use (<10%). Cox proportional hazards regression models were used to calculate the relative risk of mortality for all patients outside each guideline. In all models, calcium values were adjusted for low serum albumin. A separate Cox survival model adjusted for all six HD practices simultaneously to account for correlation that may exist between some facility practices. All models were adjusted for age, sex, race, time on ESRD, and 14 summary comorbid conditions. Patient years attributable to each of the six practice patterns were estimated and are reported here as the potential patient years gained. Comparison of the estimates by individual guideline shows that, in Spain, increasing patient albumin above 40 g/L in all patients would lead to an estimated gain of 9,269 patient years (a 7.9% increase). Additionally, if all facilities could decrease catheter use to less than 10%, 2,842 patient years could be gained (a 2.4% increase). Though it may be an unrealistic goal, if all Spanish patients currently outside the guidelines achieved all six target levels, an estimated 17,300 life years could be gained over the next five years (a 15% increase). A more achievable goal of bringing 50% of patients who are currently outside targets within targets would result in 9,266 life years gained. In conclusion, this analysis suggests large opportunities to improve HD patient care in Spain.

Mortality risk for patients receiving hemodiafiltration versus hemodialysis: European results from the DOPPS

Hemodiafiltration (HDF) is used sporadically for renal replacement therapy in Europe but not in the US. Characteristics and outcomes were compared for patients receiving HDF versus hemodialysis (HD) in five European countries in the Dialysis Outcomes and Practice Patterns Study. The study followed 2165 patients from 1998 to 2001, stratified into four groups: low- and high-flux HD, and low- and high-efficiency HDF. Patient characteristics including age, sex, 14 comorbid conditions, and time on dialysis were compared between each group using multivariate logistic regression. Cox proportional hazards regression assessed adjusted differences in mortality risk. Prevalence of HDF ranged from 1.8% in Spain to 20.1% in Italy. Compared to low-flux HD, patients receiving low-efficiency HDF had significantly longer average duration of end-stage renal disease (7.0 versus 4.7 years), more history of cancer (15.4 versus 8.7%), and lower phosphorus (5.3 versus 5.6 mg/dl); patients receiving high-efficiency HDF had significantly more lung disease (15.5 versus 10.2%) and received a higher single-pool Kt/V (1.44 versus 1.35). High-efficiency HDF patients had lower crude mortality rates than low-flux HD patients. After adjustment, high-efficiency HDF patients had a significant 35% lower mortality risk than those receiving low-flux HD (relative risk=0.65, P=0.01). These observational results suggest that HDF may improve patient survival independently of its higher dialysis dose. Owing to possible selection bias, the potential benefits of HDF must be tested by controlled clinical trials before recommendations can be made for clinical practice.

Geographic differences in event rates by model for end-stage liver disease score

The ability of the model for end-stage liver disease (MELD) score to accurately predict death among liver transplant candidates allows for evaluation of geographic differences in transplant access for patients with similar death risk. Adjusted models of time to transplant and death for adult liver transplant candidates listed between 2002 and 2003 were developed to test for differences in MELD score among Organ Procurement and Transplantation Network (OPTN) regions and Donation Service Areas (DSA). The average MELD and relative risk (RR) of death varied somewhat by region (from 0.82 to 1.28), with only two regions having significant differences in RRs. Greater variability existed in adjusted transplant rates by region; 7 of 11 regions differed significantly from the national average. Simulation results indicate that an allocation system providing regional priority to candidates at MELD scores > or = 15 would increase the median MELD score at transplant and reduce the total number of deaths across DSA quintiles. Simulation results also indicate that increasing priority to higher MELD candidates would reduce the percentage variation among DSAs of transplants to patients with MELD scores > or = 15. The variation decrease was due to increasing the MELD score at time of transplantation in the DSAs with the lowest MELD scores at transplant.

Longer treatment time and slower ultrafiltration in hemodialysis: Associations with reduced mortality in the DOPPS

Longer treatment time (TT) and slower ultrafiltration rate (UFR) are considered advantageous for hemodialysis (HD) patients. The study included 22,000 HD patients from seven countries in the Dialysis Outcomes and Practice Patterns Study (DOPPS). Logistic regression was used to study predictors of TT > 240 min and UFR > 10 ml/h/kg bodyweight. Cox regression was used for survival analyses. Statistical adjustments were made for patient demographics, comorbidities, dose of dialysis (Kt/V), and body size. Europe and Japan had significantly longer (P < 0.0001) average TT than the US (232 and 244 min vs 211 in DOPPS I; 235 and 240 min vs 221 in DOPPS II). Kt/V increased concomitantly with TT in all three regions with the largest absolute difference observed in Japan. TT > 240 min was independently associated with significantly lower relative risk (RR) of mortality (RR = 0.81; P = 0.0005). Every 30 min longer on HD was associated with a 7% lower RR of mortality (RR = 0.93; P < 0.0001). The RR reduction with longer TT was greatest in Japan. A synergistic interaction occurred between Kt/V and TT (P = 0.007) toward mortality reduction. UFR > 10 ml/h/kg was associated with higher odds of intradialytic hypotension (odds ratio = 1.30; P = 0.045) and a higher risk of mortality (RR = 1.09; P = 0.02). Longer TT and higher Kt/V were independently as well as synergistically associated with lower mortality. Rapid UFR during HD was also associated with higher mortality risk. These results warrant a randomized clinical trial of longer dialysis sessions in thrice-weekly HD.

Report of a National Conference on Donation after cardiac death

A national conference on organ donation after cardiac death (DCD) was convened to expand the practice of DCD in the continuum of quality end-of-life care. This national conference affirmed the ethical propriety of DCD as not violating the dead donor rule. Further, by new developments not previously reported, the conference resolved controversy regarding the period of circulatory cessation that determines death and allows administration of pre-recovery pharmacologic agents, it established conditions of DCD eligibility, it presented current data regarding the successful transplantation of organs from DCD, it proposed a new framework of data reporting regarding ischemic events, it made specific recommendations to agencies and organizations to remove barriers to DCD, it brought guidance regarding organ allocation and the process of informed consent and it set an action plan to address media issues. When a consensual decision is made to withdraw life support by the attending physician and patient or by the attending physician and a family member or surrogate (particularly in an intensive care unit), a routine opportunity for DCD should be available to honor the deceased donor's wishes in every donor service area (DSA) of the United States.

Mortality after kidney transplantation: a comparison between the United States and Canada

There is a paucity of comparative studies on country-specific outcomes in kidney transplantation. We compared post-transplant mortality among primary, adult, solitary kidney transplant recipients (KTR) from the United States (n = 70 708) and Canada (n = 5773), between January 1, 1991 and December 31, 1998, using data from the Scientific Registry of Transplant Recipients and the Canadian Organ Replacement Register. Multivariable Cox regression revealed higher adjusted post-transplant mortality among U.S. (vs. Canadian) KTR (HR = 1.35 [95% CI 1.24, 1.47; p < 0.005]). Mortality risk in the first post-transplant year was similar in both countries but higher in the United States beyond the first year (HR = 1.49-1.53; p < 0.005). There was no difference in mortality among patients transplanted within 1 year of starting dialysis, but mortality was increased in U.S. (vs. Canadian) patients after 1-2 and 4+ years on dialysis (HR = 1.36-1.66; p < 0.005). Greater mortality was also seen in U.S. patients with diabetes mellitus and/or graft failure. In conclusion, there are considerable differences in the survival of KTR in the United States and Canada. A detailed examination of factors contributing to this variation may yield important insights into improving outcomes for all KTR.

Estimating the impact of renal replacement therapy choice on outcome in severe acute renal failure

BACKGROUND

Mortality in severe acute renal failure (ARF) requiring renal replacement therapy (RRT) approximates 50% and varies with clinical severity. Continuous RRT (CRRT) has theoretical advantages over intermittent hemodialysis (IHD) for critical patients, but a survival advantage with CRRT is yet to be clearly demonstrated. To date, no prospective controlled trial has sufficiently answered this question, and the present prospective outcome study attempts to compare survival with CRRT versus that with IHD.

METHODS

Multivariable Cox-proportional hazards regression was used to analyze the impact of RRT modality choice (CRRT vs. IHD) on in-hospital and 100-day mortality among ARF patients receiving RRT during 2000 and 2001 at University of Michigan, using an "intent-to-treat" analysis adjusted for multiple comorbidity and severity factors.

RESULTS

Overall in-hospital mortality before adjustment was 52%. Triage to CRRT (vs IHD) was associated with higher severity and unadjusted relative rate (RR) of in-hospital death (RR = 1.62, p = 0.001, n = 383). Adjustment for comorbidity and severity of illness reduced the RR of death for patients triaged to CRRT and suggested a possible survival advantage (RR = 0.81, p = 0.32). Analysis restricted to patients in intensive care for more than five days who received at least 48 hours of total RRT, showed the RR of in-hospital mortality with CRRT to be nearly 45% lower than IHD (RR = 0.56, n = 222), a difference in RR that indicates a strong trend for in-hospital mortality with borderline statistical significance (p = 0.069). Analysis of 100-day mortality also suggested a potential survival advantage for CRRT in all cohorts, particularly among patients in intensive care for more than five days who received at least 48 h of RRT (RR = 0.60, p = 0.062, n = 222).

CONCLUSION

Applying the present methodology to outcomes at a single tertiary medical center, CRRT may appear to afford a survival advantage for patients with severe ARF treated in the ICU. Unless and until a prospective controlled trial is realized, the present data suggest potential survival advantages of CRRT and support broader application of CRRT among such critically ill patients.

[Results of the international hemodialysis study DOPPS in Spain and Europe]

The Dialysis Outcomes and Practice Pattern Study (DOPPS) is an international observational study of treatment conditions and medical outcomes in hemodialysis patients. Prospective sampling has yielded long-term observational data from randomly selected groups of patients receiving treatment at representative, randomly selected hemodialysis units in each country. The data shown were collected at 20 hemodialysis units/centers in Spain. The data pertaining to Spain--Sp--refers to 575 patients and their comparison with those of the Euro-DOPPS countries--Eu--(Germany, France, United Kingdom, Italy and Spain), which encompass 3,038 patients, represent the formal goal of this paper. Diabetes mellitus, at 21.5% in Eu and 21.7% in Sp, was the most common cause of renal insufficiency in dialysis and coronariopathy, as a concomitant disease, was present in 67.8% in Eu as opposed to 75.8% in Sp. Differences were observed in the incident of hypertension (73.4% in Eu vs 77.4% in Sp), hepatitis C (11.6% vs 19.5%), depression (12.7 vs 16.2%) and left ventricular hypertrophy (54.9% vs 62.3%). The patterns of vascular access were similar (79% vs 81% AV fistulas in Eu and Sp, and 10% synthetic grafts for both) and the mean applied dose of dialysis--Kt/V--smaller (1.19) in Sp than in Eu (1.24); likewise the duration of the dialysis (in minutes) was shorter (234 in Eu vs 217 in Sp) and the % of synthetic membranes used was smaller (60% in Eu vs 52% in Sp). There were no differences between the groups in the figures for urea, creatinine, albumin, nPCR, calcium, phosphate or PTH. There were also no differences in the mean values of Hb (10.7 for Eu vs 10.8 for Sp), given that the values of ferritin were noticeably lower in Sp (288 vs 355) and the dose of EPO/kg/week was higher to in Sp (115 vs 102); s.c. route was used in similar proportions (69% in Eu vs 67% in Sp). The level of medical care, understood as contact with the physician at all or almost all treatments, was noticeably better in Sp (90%) that in Eu (66%), whereas the number of patients per hour of specialized personnel and % of specialized staff, were smaller. Mortality (death/100 patients-years) was one point lower in Sp than in Eu (15.4 vs 16.3). These data suggest that an increment in dialysis time and in the percentage of synthetic membranes used, as well as in the supply of intravenous iron, would be justified.

Race and glomerulonephritis in patients with and without hepatosplenic Schistosomiasis mansoni

BACKGROUND/AIMS

United States investigators have shown evidence of higher susceptibility to focal segmental glomerulosclerosis (FSGS) in blacks than in whites. This association between race and FSGS has not been assessed outside the US. The present study assesses the association between race and type of glomerulonephritis in a sample of Brazilian patients, taking into account the presence of the hepatosplenic form of Schistosomiasis mansoni (HSM).

METHODS

Eighty patients with focal segmental glomerulosclerosis (FSGS) were compared to 50 with membranoproliferative glomerulonephritis (MPGN). The association between race (i.e. black versus white) and type of glomerulonephritis was adjusted for age, gender and HSM by logistic regression.

RESULTS

Blacks were more likely than whites to have FSGS (as compared to MPGN), both among patients with HSM (odds ratio (OR) = 2.67; 95% confidence interval (CI) = 0.81 - 8.81) and without HSM (OR = 2.19; 95% CI = 0.79 - 6.05). After adjustment for age, gender and HSM, the odds of FSGS remained significantly greater for blacks (OR = 2.49; 95% CI = 1.05 - 5.95).

CONCLUSION

The increased likelihood of FSGS in Brazilian blacks is consistent with findings from US patients. The association between race and type of glomerulonephritis was similar between patients with and without HSM. Future investigations should focus on the mediators factors that might explain these findings.

Cardiovascular mortality in children and young adults with end-stage kidney disease

OBJECTIVE

To analyze cardiovascular death in a national end-stage renal disease (ESRD) population.

STUDY DESIGN

This retrospective, observational study with data from the US Renal Data Systems analyzed 1380 deaths from 1990 to 1996 among patients who started ESRD therapy as children and died before 30 years of age.

RESULTS

Percentage of cardiac deaths (n = 311) varied by age and was higher among black patients (0-4 years, 36%; 5-9 years, 18%; 10-14 years, 35%; 15-19 years, 22%; 20-30 years, 32%) than white patients (18%, 12%, 17%, 14%, and 23%, respectively). Among black patients, cardiac deaths occurred in 11% of transplant recipients, 34% of dialysis patients, and among white patients 9% and 25%, respectively. Black patients were 1.6 times more likely to die of a cardiac death (P <.001) than white patients. Transplant recipients had 78% lower risk of cardiac death than dialysis patients (odds ratio = 0.22; P =.0001). The cardiac death rate among dialysis patients was 21.4 per 1000 patient-years in black patients compared with 20.5 in white patients. Transplantation cardiac death rates were lower in black patients, 2.1 per 1000 patient-years, and 1.3 in white patients.

CONCLUSIONS

Cardiovascular death accounts for 23% of pediatric and young adult ESRD deaths. Black patients and dialysis patients are at higher risk of a cardiac death compared with white patients and transplant recipients. Further studies are needed to identify risk factors associated with cardiovascular death in patients with ESRD.

[Dialysis Outcomes and Practice Patterns Study: data on the use of central venous catheters in chronic hemodialysis]

Central venous catheters are widely used as vascular accesses for chronic haemodialysis. Different factors may lead to catheter use, whether clinical such as emergency dialysis, or related to practices specific to each dialysis unit or country. The Dialysis Outcomes and Practice Patterns Study is an observational study of more than 10,000 representative patients treated by haemodialysis followed over a two-year period in the United States, Japan, and in five European countries (France, Germany, Italy, Spain, United Kingdom). DOPPS data from the United States and Europe about catheters are reported in this paper. Catheter use is less frequent in Europe than in the US, both in incident and prevalent patients, and in patients who have been seen by a nephrologist in the pre-dialysis period. Tunneled and untunneled catheters are each associated with a significantly higher frequency of access infection compared to native arteriovenous fistulae and grafts. Patients with important comorbidities such as diabetes, cardiovascular diseases, malnutrition or dementia are more likely to be dialysed with tunneled catheters. Furthermore, patients initiating hemodialysis with a tunneled catheter display higher mortality risk compared to patients starting hemodialysis with a permanent access. In summary, DOPPS data indicate that central venous catheters are used for chronic haemodialysis in patients with a high level of morbidity, and that their utilisation is associated to an additional risk, particularly of infection, and to a lower survival for tunneled catheters. Appropriate care should limit the utilisation of central venous catheters to clinically undisputable indications.

Use of ACE inhibitors is associated with prolonged survival of arteriovenous grafts

Vascular access complications are common in hemodialysis patients. To investigate whether the use of angiotensin-converting enzyme (ACE) inhibitors influences the rate of polytetrafluoroethylene (PTFE) graft complications, we compared the rate of intervention-free graft survival among patients treated versus not treated with ACE inhibitors. We retrospectively analyzed the survival of grafts placed at our institution between January 1, 1995, and October 31, 1999. Among 121 grafts, 25 grafts were placed in 19 patients treated with ACE inhibitors and 96 grafts were placed in 68 patients not treated with ACE inhibitors. Follow-up ranged from 1 month to 5 years. Ten of 25 grafts failed in the ACE-inhibitor group and 62 of 95 grafts failed in the non-ACE-inhibitor group. Actuarial intervention-free access survival rates (Kaplan-Meier) were significantly greater in the ACE-inhibitor than non-ACE-inhibitor group (71% versus 53% at 6 months, 58% versus 35% at 12 months, and 44% versus 22% at 24 months; P = 0.04). Using a Cox model adjusting for age, race, sex, and diabetes, the relative risk (RR) for access failure in the ACE-inhibitor group was 53% less than in the non-ACE-inhibitor group (RR, 0.47; p < 0.03). In a more complex Cox model with additional adjustment for comorbid conditions, the RR was even lower (RR, 0.32; P = 0.003) for the ACE-inhibitor compared with non-ACE-inhibitor group (reference = 1.00). The lower RR was observed for patients with and without congestive heart failure. These results suggest that ACE inhibitors offer clinical promise in the prevention of PTFE graft failure. A prospective randomized trial is warranted to confirm the benefit of ACE inhibitors.

Body mass index and mortality in 'healthier' as compared with 'sicker' haemodialysis patients: results from the Dialysis Outcomes and Practice Patterns Study (DOPPS)

BACKGROUND

Haemodialysis (HD) patients with lower body mass index (BMI) have a higher relative mortality risk (RR), irrespective of race. However, only Asian Americans treated with HD have been found to have an elevated RR with higher BMI. Asian Americans on HD are 'healthier' than other race groups (i.e. have better overall survival). We hypothesized that an increased mortality risk might be associated with high BMI in a variety of other 'healthier' subgroups of HD patients.

METHODS

The prospective Dialysis Outcomes and Practice Patterns Study (DOPPS) provided baseline demographic, comorbidity and BMI data on 9714 HD patients in the US and Europe (France, Germany, Italy, Spain, and the UK) from 1996-2000. Using multivariate survival analyses, we evaluated BMI-mortality relationships in HD subpopulations defined by continent, race (black and white), gender, tertiles of severity of illness (based on a score derived from comorbid conditions and serum albumin concentration), age (<45, 45-64, >or=65), smoking, and diabetic status.

RESULTS

Relative mortality risk decreased with increasing BMI. This was statistically significant (P<0.007) except for the smallest subgroup of patients who were <45 years old and were also in the healthiest tertile of comorbidity. All else equal, BMI <20 was consistently associated with the highest relative mortality risk. Overall a lower relative mortality risk (RR) as compared with BMI 23-24.9, was found for overweight (BMI 25-29.9; RR 0.84, P=0.008), for mild obesity (BMI 30-34.9; RR 0.73, P=0.0003), and for moderate obesity (BMI 35-39.9; RR 0.76, P=0.02).

CONCLUSION

In a wide variety of HD patient subgroups, differing with respect to their baseline health status, increasing body size correlates with a decreased mortality risk. This contrasts with the association between BMI and mortality in the general population, and deserves further study.

Type of vascular access and mortality in U.S. hemodialysis patients

BACKGROUND

Vascular access (VA) complications account for 16 to 25% of hospital admissions. This study tested the hypothesis that the type of VA in use is correlated with overall mortality and cause-specific mortality.

METHODS

Data were analyzed from the U.S. Renal Data System Dialysis Morbidity and Mortality Study Wave 1, a random sample of 5507 patients, prevalent on hemodialysis as of December 31, 1993. The relative mortality risk during a two-year observation was analyzed by Cox-regression methods with adjustments for demographic and comorbid conditions. Using similar methods, cause-specific analyses also were performed for death caused by infection and cardiac causes.

RESULTS

In diabetic mellitus (DM) patients with end-stage renal disease, the associated relative mortality risk was higher for those with arteriovenous graft (AVG; RR = 1.41, P < 0.003) and central venous catheter (CVC; RR = 1.54, P < 0.002) as compared with arteriovenous fistula (AVF). In non-DM patients, those with CVC had a higher associated mortality (RR = 1.70, P < 0.001), as did to a lesser degree those with AVG (RR = 1.08, P = 0.35) when compared with AVF. Cause-specific analyses found higher infection-related deaths for CVC (RR = 2.30, P < 0.06) and AVG (RR = 2.47, P < 0.02) compared with AVF in DM; in non-DM, risk was higher also for CVC (RR = 1.83, P < 0.04) and AVG (RR = 1.27, P < 0.33). In contrast to our hypothesis that AV shunting increases cardiac risk, deaths caused by cardiac causes were higher in CVC than AVF for both DM (RR = 1.47, P < 0.05) and non-DM (RR = 1.34, P < 0.05) patients.

CONCLUSION

This case-mix adjusted analysis suggests that CVC and AVG are correlated with increased mortality risk when compared with AVF, both overall and by major causes of death.

Incidence trends and mortality in end-stage renal disease attributed to renovascular disease in the United States

End-stage renal disease (ESRD) attributed to renovascular disease (RVD-ESRD) has been incompletely characterized. We determined incidence trends, clinical features, prior treatment, and survival of patients with RVD-ESRD using the US Renal Data System database. Primary causes of ESRD were assessed in patients starting ESRD therapy during 1991 to 1997. The incidence of RVD-ESRD increased from 2.9/10(6) per year (1.4% of new ESRD cases) to 6.1/10(6) per year (2.1%). The annualized increase was 12.4% per year. This is a greater rate of increase than for ESRD from diabetes mellitis (DM-ESRD; 8.3% per year) and ESRD overall (5.4% per year). The risk for RVD-ESRD versus other-cause ESRD correlated positively with age (odds ratio [OR], 1.7 per 10-year increment; P < 0.0001) and male sex (OR, 1.2; P < 0.0001) and negatively with black (OR, 0.17; P < 0.0001), Asian (OR, 0.29; P < 0.0001), and Native American race (OR, 0.31; P < 0.0001). The unadjusted prevalence of coronary heart disease, cerebrovascular disease, and peripheral vascular disease was greater in patients with RVD-ESRD versus other-cause ESRD (P < 0.001). Of patients with RVD-ESRD, 5% underwent revascularization in the 2 years before ESRD compared with 0.5% of patients with other-cause ESRD, including DM-ESRD. Adjusted for age, race, sex, comorbidity, and laboratory values, the survival of patients with RVD-ESRD was similar to that for patients with other-cause ESRD (risk ratio, 1.01; P = 0.5). These findings suggest that RVD-ESRD is increasing faster than other-cause ESRD and is not independently associated with an increased mortality risk. Strategies may exist to prevent progression to ESRD and merit priority for further study.

Description and clinical outcomes of peritoneal dialysis: analyses from the United States Renal Data System

USRDS studies provide results that are consistent when considering the effect of time since the onset of ESRD in comparisons of PD and HD outcomes. The results are representative of patient selection and practice in the U.S., but may not apply in other countries, where patients are selected to PD using very different criteria. In international comparisons, even adjustment for comorbid conditions may not fully compensate for selection. The analytical experience from the USRDS may serve as a model for similar analyses in environments where different practices and registries are used.

Mortality risk by hemodialyzer reuse practice and dialyzer membrane characteristics: results from the usrds dialysis morbidity and mortality study

Hemodialyzer reuse is commonly practiced in the United States. Recent studies have raised concerns about the mortality risk associated with certain reuse practices. We evaluated adjusted mortality risk during 1- to 2-year follow-up in a representative sample of 12,791 chronic hemodialysis patients treated in 1,394 dialysis facilities from 1994 through 1995. Medical record abstraction provided data on reuse practice, use of bleach, dialyzer membrane, dialysis dose, and patient characteristics and comorbidity. Mortality risk was analyzed by bootstrapped Cox models by (1) no reuse versus reuse, (2) reuse agent, and (3) dialyzer membrane with and without the use of bleach, while considering dialysis and patient factors. The relative risk (RR) for mortality did not differ for patients in reuse versus no-reuse units (RR = 0.96; 95% confidence interval [CI], 0.86 to 1.08; P > 0.50), and similar results were found with different levels of adjustment and subgroups (RR = 1.01 to 1.05; 95% CI, lower bound > 0.90, upper bound < 1.19 each; each P > 0.40). The RR for peracetic acid mixture versus formalin varied significantly by membrane type and use of bleach during reprocessing, achieving borderline significance for synthetic membranes. Among synthetic membranes, mortality was greater with low-flux than high-flux membranes (RR = 1.24; 95% CI, 1.02 to 1.52; P = 0.04) and without than with bleach during reprocessing (RR = 1.24; 95% CI, 1.01 to 1.48; P = 0.04). Among all membranes, mortality was lowest for patients treated with high-flux synthetic membranes (RR = 0.82; 95% CI, 0.72 to 0.93; P = 0.002). Although mortality was not greater in reuse than no-reuse units overall, differences may exist in mortality risk by reuse agent. Use of high-flux synthetic membrane dialyzers was associated with lower mortality risk, particularly when exposed to bleach. Clearance of larger molecules may have a role.

The impact of simultaneous pancreas-kidney transplantation on long-term patient survival

BACKGROUND

Simultaneous pancreas-kidney transplantation (SPK) ameliorates the progression of microvascular diabetic complications but the procedure is associated with excess initial morbidity and an uncertain effect on patient survival when compared with solitary cadaveric or living donor renal transplantation. We evaluated mortality risks associated with SPK, solitary renal transplantation, and dialysis treatment in a national cohort of type 1 diabetics with end-stage nephropathy.

METHODS

A total of 13,467 adult-type 1 diabetics enrolled on the renal and renal-pancreas transplant waiting list between 10/01/88 and 06/30/97 were followed until 06/30/98. Time-dependent mortality risks and life expectancy were calculated according to the treatment received subsequent to wait-list registration: SPK; cadaveric kidney only (CAD); living donor kidney only (LKD) transplantation; and dialysis [wait-listed, maintenance dialysis treatment (WLD)].

RESULTS

Adjusted 10-year patient survival was 67% for SPK vs. 65% for LKD recipients (P=0.19) and 46% for CAD recipients (P<0.001). The excess initial mortality normally associated with renal transplantation and the risk of early infectious death was 2-fold higher in SPK recipients. The time to achieve equal proportion of survivors as the WLD patients was 170, 95, and 72 days for SPK, CAD, and LKD recipients, respectively (P<0.001). However, the adjusted 5-year morality risk (RR) using WLD as the reference and the expected remaining life years were 0.40, 0.45, and 0.75 and 23.4, 20.9, and 12.6 years for SPK, LKD, and CAD, respectively. There was no survival benefit in SPK recipients > or =50 years old (RR=1.38, P=0.81).

CONCLUSIONS

Among patients with type 1 DM with end-stage nephropathy, SPK transplantation before the age of 50 years was associated with long-term improvement in survival compared to solitary cadaveric renal transplantation or dialysis.

Cross-sectional and longitudinal predictors of serum albumin in hemodialysis patients

BACKGROUND

Lower serum albumin concentrations predict increased mortality in hemodialysis (HD) patients. Many demographic, comorbidity, and modifiable treatment-related factors that predict HD patient outcomes may be associated with serum albumin.

METHODS

Cross-sectional predictors of baseline albumin on December 31, 1993 were sought (N = 3981). Additional effects of the same baseline predictors on subsequent trends in albumin over one year were examined in a nested subsample of patients (N = 2245). Wave-1 of the United States Renal Data System Dialysis Morbidity and Mortality special study provided the data.

RESULTS

Significant associations (P < 0.05) are summarized as older age, female gender, peripheral vascular disease, chronic obstructive pulmonary disease, and cancer predicted a lower baseline albumin and negatively influenced subsequent albumin trends. Baseline albumin was higher for blacks (vs. whites), lower for smoking and diabetes, and lower during the first year of HD treatment (<3 months and 3 to 12 months, vs.> 1 year). Trend analysis showed more positive albumin slopes for patients in their first year on HD and more negative slopes for Native Americans (vs. whites). Baseline albumin was correlated with the type of vascular access being used [arteriovenous (AV) fistulas > AV grafts > permanent catheters > temporary catheters]. Trend analysis predicted more negative albumin slopes for AV grafts and permanent catheters (vs. AV fistula access). Baseline albumin correlated inversely with bicarbonate and directly with hematocrit. Dialysis with unmodified cellulose membranes, without reuse, predicted lower baseline albumin than the other membrane-reuse categories.

CONCLUSIONS

Several exposures, which may be modifiable, were associated with serum albumin.

Characteristics and treatment of patients not reusing dialyzers in reuse units

Dialyzer reuse is practiced in more than 75% of the patients and dialysis units in the United States. However, reuse is not practiced in a small fraction of patients treated in reuse units (RUUs). This study evaluates both patient and facility characteristics associated with nonreuse in RUUs. The data source is from the Dialysis Mortality and Morbidity Study, Waves 1, 3, and 4, of the US Renal Data System. Only facilities that practiced dialyzer reuse were included in the analysis. A total of 12,094 patients from 1,095 reuse facilities were studied. Patients undergoing hemodialysis as of December 31, 1993, were selected. Of all patients treated in RUUs, 8% did not reuse dialyzers. Nonreuse was significantly (P < 0.02) more common, based on adjusted odds ratios (ORs), among patients who were younger (OR = 1.16 per 10 years younger), had primary glomerulonephritis (OR = 1.26 versus diabetes), had lower serum albumin level (OR = 1.72 per 1 g/dL lower), had more years on dialysis, and had higher level of education. Nonreuse patients were more likely to be treated with low-flux dialyzers (OR = 7.35; P < 0. 0001) and have a lower dialysis dose. No reuse was more likely in larger units and in not-for-profit and hospital-based units. Patient refusal accounted for one fourth of nonreuse in RUUs and was associated with the same factors, as well as with fewer comorbid conditions and non-Hispanic ethnicity. Significant geographic variations (up to eightfold) were documented. Nonreuse patients are treated with smaller, low-flux dialyzers and, on average, receive a lower Kt/V than reuse patients in the same units.

Differences in access to cadaveric renal transplantation in the United States

This national study compares waitlisting and transplantation rates by gender, race, and diabetes and evaluates physiologic factors (panel-reactive antibodies [PRA], blood type, HLA matchability) and related practices (early and multiple waitlisting) as explanatory factors. This longitudinal study of the time to transplant waitlisting among 228,552 incident end-stage renal disease (ESRD) dialysis patients and to cadaveric transplantation among 46,164 waitlist dialysis patients (n = 23,275 first cadaveric transplants) used US data for 1991 to 1997. Relative rates of waitlisting (RRWL) after ESRD onset and of cadaveric transplantation (RRTx) after waitlist (Cox proportional hazards models) were adjusted for age, race, sex, ESRD cause, region, and incidence/waitlist year. We found that women have an RRWL = 0.84 (P < 0.0001) and RRTx = 0.86 (P < 0. 0001). PRA levels can explain the difference in the transplantation rate, because accounting for PRA gives an adjusted RRTx = 0.98 (NS) for women. For blacks versus whites, the RRWL = 0.59 (P < 0.0001) and RRTx = 0.55 (P < 0.0001). However, the transplantation rate can only partly be explained by ABO types, rare HLA types, and early and multiple waitlisting (adjusted RRTx = 0.67 [P < 0.0001]). For diabetes versus glomerulonephritis, the RRWL = 0.52 (P < 0.0001) and RRTx = 0.98 (NS). Older patients (40 to 59 years of age) are less likely to be waitlisted and to receive a transplant after waitlisting (RRWL = 0.57 [P < 0.0001], RRTx = 0.88 [P < 0.0001]) versus younger patients (ages 18 to 39 years). These results indicate substantial differences by age, sex, race, and diabetes in rates of waitlisting for transplantation and by age and race for transplantation after waitlisting. These differences by race were not explained by referral practices or the physiologic factors studied here.

Effect of waiting time on renal transplant outcome

BACKGROUND

Numerous factors are known to impact on patient survival after renal transplantation. Recent studies have confirmed a survival advantage for renal transplant patients over those waiting on dialysis. We aimed to investigate the hypothesis that longer waiting times are more deleterious than shorter waiting times, that is, to detect a "dose effect" for waiting time.

METHODS

We analyzed 73,103 primary adult renal transplants registered at the United States Renal Data System Registry from 1988 to 1997 for the primary endpoints of death with functioning graft and death-censored graft failure by Cox proportional hazard models. All models were corrected for donor and recipient demographics and other factors known to affect outcome after kidney transplantation.

RESULTS

A longer waiting time on dialysis is a significant risk factor for death-censored graft survival and patient death with functioning graft after renal transplantation (P < 0.001 each). Relative to preemptive transplants, waiting times of 6 to 12 months, 12 to 24 months, 24 to 36, 36 to 48, and over 48 months confer a 21, 28, 41, 53, and 72% increase in mortality risk after transplantation, respectively. Relative to preemptive transplants, waiting times of 0 to 6 months, 6 to 12 months, 12 to 24 months, and over 24 months confer a 17, 37, 55, and 68% increase in risk for death-censored graft loss after transplantation, respectively.

CONCLUSIONS

Longer waiting times on dialysis negatively impact on post-transplant graft and patient survival. These data strongly support the hypothesis that patients who reach end-stage renal disease should receive a renal transplant as early as possible in order to enhance their chances of long-term survival.

Relationship of recipient age and development of chronic allograft failure

BACKGROUND

The elderly are the fastest growing segment of the end stage renal disease (ERSD) population. Older renal transplant recipients experience fewer acute rejection episodes than do younger patients. Despite this, death censored graft survival is no better in these older transplant recipients than in younger recipients. We examined the United States Renal Data System (USRDS) database to determine whether recipient age itself has an independent effect on the development of chronic allograft failure (CAF).

METHODS

We analyzed 59,509 patients from the files of the USRDS. To determine whether age was an independent risk factor for CAF, the population was analyzed separately for Caucasians, African-Americans, and other ethnic groups. All renal transplant recipients from 1988 to 1997 were examined. Both univariate and multivariate analysis were performed using chronic allograft failure as the outcome of interest.

RESULTS

Actuarial 8-year censored graft survival was significantly decreased in the older age groups 67% for ages 18-49 vs. 61.8% for ages 50-64 vs. 50.7% for ages 65+ (P<0.001). In the multivariate analysis, recipient age was a strong and independent risk factor for the development of chronic allograft failure in Caucasians (RR 1.29 for ages 50-64, RR 1.67 for ages older than 65). These findings were reinforced by an analysis that was restricted to living donor transplants without acute rejection.

CONCLUSION

In Caucasians increased recipient age is an independent risk factor for the development of chronic renal allograft failure.

Impact of pre-existing donor hypertension and diabetes mellitus on cadaveric renal transplant outcomes

Hypertension (HTN) and diabetes mellitus (DM) predispose to systemic atherosclerosis with renal involvement. The prevalence of HTN and DM in cadaveric renal donors (affected donors) and the results of transplantation are unknown. We investigated these issues with national data from the US Renal Data System. A total of 4,035 transplants from affected donors were matched 1:1 with unaffected controls according to donor age and race, recipient race, and year of transplantation. Graft and patient survival were estimated. Among the 25,039 solitary renal transplantations performed between July 1, 1994, and June 30, 1997, cadaveric renal transplants from donors with HTN accounted for 15%, and donors with DM, 2%. Programs with 1-year cadaveric renal graft survival rates greater than 90% had 50% less affected donors compared with programs having 1-year cadaveric renal graft survival rates of 85% or less. Compared with donor-age-matched controls, transplants from affected donors were at minimally increased risk for primary nonfunction, delayed graft function, and acute rejection. Three-year graft survival rates were 71% in affected donor organs and 75% in controls (P = 0.001). Compared with controls, duration of HTN was an independent risk factor for graft survival (3-year graft survival rates, 75% versus 65%; relative risk = 1.36 for HTN >10 years; P < 0.001). A substantial fraction of cadaveric renal donors have preexisting HTN. Programs transplanting fewer affected donor kidneys had better than average results. Because the negative impact of donor HTN and DM on transplant outcome was of moderate degree except when the duration of donor HTN was greater than 10 years, use of affected donors should not be discouraged, but graft and patient survival analyses should account for their presence.

Re-evaluation of risks associated with hyperphosphatemia and hyperparathyroidism in dialysis patients: recommendations for a change in management

Hyperphosphatemia is a predictable consequence of chronic renal failure and is present in most patients on dialysis. Traditionally, the risk associated with elevated serum phosphorus has focused on its impact on renal osteodystrophy. A growing body of evidence, however, suggests that abnormalities in serum phosphorus, calcium-phosphorus product (CaxP), and parathyroid hormone (PTH) levels are resulting in vascular and visceral calcification, thereby contributing to the substantially increased risk of cardiovascular death in this population. In this analysis, we review in detail the literature that describes these associations. We show that the current treatment paradigm for serum phosphorus and secondary hyperparathyroidism is ineffective for a large segment of dialysis patients. Currently, 60% of hemodialysis patients have phosphorus greater than 5.5 mg/dL, and 40% have CaxP greater than 60 mg(2)/dL(2). It is our belief that prevention of uremic calcification, cardiac death, and vascular disease should assume primary importance when evaluating the risks associated with elevated levels of phosphorus, CaxP, and PTH. We recommend that target levels should become 9.2 to 9.6 mg/dL for calcium, 2.5 to 5.5 mg/dL for phosphorus, less than 55 mg(2)/dL(2) for CaxP product, and 100 to 200 pg/mL for intact PTH.

Long-term survival in renal transplant recipients with graft function

Long-term survival in renal transplant recipients with graft function.

BACKGROUND

Death with graft function (DWGF) is a common cause of graft loss. The risks and determinants of DWGF have not been studied in a recent cohort of renal transplant recipients. We performed a population-based survival analysis of U.S. patients with end-stage renal disease (ESRD) transplanted between 1988 and 1997.

METHODS

Registry data were used to evaluate long-term patient survival and cause-specific risks of DWGF in 86,502 adult (>/=18 years) renal transplant recipients.

RESULTS

Out of 18,482 deaths, 38% (N = 7040) were deaths with graft function. This accounts for 42. 5% of all graft loss. Patient survival with graft function was 97, 91, and 86% at 1, 5, and 10 years, respectively. The risk of DWGF decreased by 67% (RR = 0.33, P < 0.001) between 1988 and 1997. The adjusted rate of DWGF was 4.6, 0.8, 2.2, and 1.4 deaths per 1000 person-years for cardiovascular disease, stroke, infections, and malignancy, respectively. The suicide rate was 15.7 versus 9.0 deaths per 100,000 person-years in the general population (P < 0. 001). In multivariate analysis, the following factors were independently and significantly predictive of DWGF: white recipient, age at transplantation, ESRD caused by hypertension or diabetes mellitus, length of pretransplant dialysis, delayed graft function, acute rejection, panel reactive antibody> 30%, African American donor race, age> 45 years, and donor death caused by cerebrovascular disease.

CONCLUSIONS

Patients with graft function have a high long-term survival. Although DWGF is a major cause of graft loss, the risk has declined substantially since 1990. Cardiovascular disease was the predominant reported cause of DWGF. Other causes vary by post-transplant time period. Attention to atherosclerotic risk factors may be the most important challenge to further improve the longevity of patients with successful renal transplants.