Comparative Analysis of Left Ventricular Geometry in Adult Nigerians with and without Chronic Kidney Disease: Results from Ibadan CRECKID STUDY

BACKGROUND

Chronic kidney disease (CKD) is associated with increased risk of cardiovascular morbidity and mortality. Left ventricular hypertrophy (LVH) is considered the strongest independent predictor of cardiovascular disease and events among CKD patients. We reported the echocardiographic left ventricular geometry in CKD patients compared to non-CKD hypertensive and apparently healthy controls in Ibadan.

MATERIALS AND METHODS

A total of 683 participants in the CRECKID STUDY comprising 220(32.2%) CKD patients, 281(41.1%) non-CKD hypertensive patients and 182(26.6%) healthy controls were included in this analysis. Basic demographic and clinical information with echocardiographic parameters were obtained.

RESULTS

Study participants in the non-CKD hypertensive group were on average older than the CKD and the healthy controls (56.2±13.1 vs 47.2±14.6, and 46.8±13.3 years, respectively; p<0.01). Compared with other groups, greater proportions of participants with CKD were men (40.5% vs.38.1% and 21.3%; p<0.0001). The left atrial and left ventricular dimensions were significantly higher in CKD compared with others. LVH was significantly more prevalent among CKD patients (68.2%) compared to hypertensive (43.9%) and normotensive (19.5%) group (p<0.01). The participants with CKD had a greater proportion of abnormal LV geometry with concentric LVH predominating (p<0.0001). Having LVH was associated with lower mean estimated glomerular filtration rate (eGFR) (40.6±37.71 vs 67±37.38, p<0.0001).

CONCLUSION

In our study, patients with CKD had the highest prevalence of abnormal LV geometry and functions. A unit decrease in eGFR was associated with increased left ventricular mass. Early detection and prompt management of abnormal LV geometry may help in reducing adverse cardiovascular outcome in patients with CKD.

Impact of MELD-based allocation on end-stage renal disease after liver transplantation

The proportion of patients undergoing liver transplantation (LT), with concomitant renal dysfunction, markedly increased after allocation by the model for end-stage liver disease (MELD) score was introduced. We examined the incidence of subsequent post-LT end-stage renal disease (ESRD) before and after the policy was implemented. Data on all adult deceased donor LT recipients between April 27, 1995 and December 31, 2008 (n = 59 242), from the Scientific Registry of Transplant Recipients, were linked with Centers for Medicare & Medicaid Services' ESRD data. Cox regression was used to (i) compare pre-MELD and MELD eras with respect to post-LT ESRD incidence, (ii) determine the risk factors for post-LT ESRD and (iii) quantify the association between ESRD incidence and mortality. Crude rates of post-LT ESRD were 12.8 and 14.5 per 1000 patient-years in the pre-MELD and MELD eras, respectively. Covariate-adjusted post-LT ESRD risk was higher in the MELD era (hazard ratio [HR]= 1.15; p = 0.0049). African American race, hepatitis C, pre-LT diabetes, higher creatinine, lower albumin, lower bilirubin and sodium >141 mmol/L at LT were also significant predictors of post-LT ESRD. Post-LT ESRD was associated with higher post-LT mortality (HR = 3.32; p < 0.0001). The risk of post-LT ESRD, a strong predictor of post-LT mortality, is 15% higher in the MELD era. This study identified potentially modifiable risk factors of post-LT ESRD. Early intervention and modification of these risk factors may reduce the burden of post-LT ESRD.

Impact of cytomegalovirus disease in D+/R- kidney transplant patients receiving 6 months low-dose valganciclovir prophylaxis

Late-onset cytomegalovirus (CMV) disease remains common in CMV serology naïve kidney transplant patients of CMV serology positive organs (D+/R-) despite the use of antiviral prophylaxis. We studied clinical efficacy of 6-month low-dose valganciclovir (VGCV) prophylaxis, risk factors for late-onset CMV disease and its impact on kidney transplant outcomes. Between October 2005 and December 2009, 166 consecutive D+/R- kidney alone and simultaneous pancreas and kidney transplant patients received VGCV 450 mg daily for 6 months after transplantation. After a median follow-up of 3.2 years, 30 cases of CMV disease occurred within the first 2 years after transplantation with a cumulative incidence of 11.5 and 18.1% at 1 and 2 years, respectively. The use of an induction agent with rabbit antithymocyte globulin and older donor age were factors associated with the risk of late-onset CMV disease (AHR 2.91, 95% CI 1.18-7.20, p = 0.021 and AHR 1.03, 95% CI 1.01-1.06, p = 0.016, respectively). Late-onset CMV disease was associated with increased risk for death-uncensored graft loss (AHR 2.95, 95% CI 1.15-7.61, p = 0.025). In conclusion, late-onset CMV disease continues to negatively impact kidney transplant outcome despite 6-month low-dose VGCV prophylaxis. Investigations focusing on novel preventive approaches should be emphasized.

Choice of induction regimens on the risk of cytomegalovirus infection in donor-positive and recipient-negative kidney transplant recipients

BACKGROUND

Late occurrence of cytomegalovirus (CMV) infection remains a concern in CMV-seronegative kidney and/or pancreas transplant recipients of CMV-seropositive organs (donor positive/recipient negative, D+/R-) despite the use of prophylaxis. We investigated the impact of various antibody induction regimens on CMV infection in this group of patients.

METHODS

A total of 254 consecutive D+/R- kidney and/or pancreas transplant patients were studied. The induction agents rabbit anti-thymocyte globulin (rATG) or basiliximab were used according to the center practice. All patients received prophylaxis with valganciclovir (VGCV) for either 3 or 6 months. The occurrence of CMV infection was confirmed by positive DNA viremia. Multivariate Cox regression analyses were performed to determine risk factors for CMV infection.

RESULTS

The cumulative incidence of CMV infection was 58, 112, and 59 cases per 1000 patient-years for patients who received no antibody induction, induction with rATG, or basiliximab induction, respectively (P=0.02). The use of rATG but not basiliximab was associated with an increased risk for CMV infection (adjusted hazard ratio [AHR] 2.13, 95% confidence interval [CI] 1.24-3.54, P=0.006). Acute rejection and its treatment with rATG were not associated with an increased risk for CMV infection when an additional course of VGCV was given following the treatment. Longer duration of prophylaxis was associated with a reduced risk for CMV infection (AHR 0.54, 95% CI 0.33-0.87, P=0.011).

CONCLUSIONS

Induction with rATG is associated with increased risk of CMV infection. Longer duration of prophylaxis is beneficial.

Influence of recipient race on the outcome of simultaneous pancreas and kidney transplantation

Racial differences on the outcome of simultaneous pancreas and kidney (SPK) transplantation have not been well studied. We compared mortality and graft survival of African Americans (AA) recipients to other racial/ethnic groups (non-AA) using the national data. We studied a total of 6585 adult SPK transplants performed in the United States between January 1, 2000 and December 31, 2007. We performed multivariate logistic regression analyses to determine risk factors associated with early graft failure and immune-mediated late graft loss. We used conditional Kaplan-Meier survival and multivariate Cox regression analyses to estimate late death-censored kidney and pancreas graft failure and death between the groups. Although there was no racial disparity in the first 90 days, AA patients had 38% and 47% higher risk for late death-censored kidney and pancreas graft failure, respectively (p = 0.006 and 0.001). AA patients were twice more likely to lose the kidney and pancreas graft due to rejection (OR 2.31 and 1.86, p = 0.002 and 0.008, respectively). Bladder pancreas drainage was associated with inferior patient survival (HR 1.42, 95% CI 1.15, 1.75, p = 0.001). In the era of modern immunosuppression, AA SPK transplant patients continue to have inferior graft outcome. Additional studies to explore the mechanisms of such racial disparity are warranted.

Database comparison of the adult-to-adult living donor liver transplantation cohort study (A2ALL) and the SRTR U.S. Transplant Registry

Data submitted by transplant programs to the Organ Procurement and Transplantation Network (OPTN) are used by the Scientific Registry of Transplant Recipients (SRTR) for policy development, performance evaluation and research. This study compared OPTN/SRTR data with data extracted from medical records by research coordinators from the nine-center A2ALL study. A2ALL data were collected independently of OPTN data submission (48 data elements among 785 liver transplant candidates/recipients; 12 data elements among 386 donors). At least 90% agreement occurred between OPTN/SRTR and A2ALL for 11/29 baseline recipient elements, 4/19 recipient transplant or follow-up elements and 6/12 donor elements. For the remaining recipient and donor elements, >10% of values were missing in OPTN/SRTR but present in A2ALL, confirming that missing data were largely avoidable. Other than variables required for allocation, the percentage missing varied widely by center. These findings support an expanded focus on data quality control by OPTN/SRTR for a broader variable set than those used for allocation. Center-specific monitoring of missing values could substantially improve the data.

Organ donation and utilization in the United States, 1999-2008

Despite the Organ Donation Breakthrough Collaborative's work to engage the transplant community and the suggested positive impact from these efforts, availability of transplanted organs over the past 5 years has declined. Living kidney, liver and lung donations declined from 2004 to 2008. Living liver donors in 2008 dropped to less than 50% of the peak (524) in 2001. There were more living donors that were older and who were unrelated to the recipient. Percentages of living donors from racial minorities remained unchanged over the past 5 years, but percentages of Hispanic/Latino and Asian donors increased, and African American donors decreased. The OPTN/UNOS Living Donor Transplant Committee restructured to enfranchise organ donors and recipients, and to seek their perspectives on living donor transplantation. In 2008, for the first time in OPTN history, deceased donor organs decreased compared to the prior year. Except for lung donors, deceased organ donation fell from 2007 to 2008. Donation after cardiac death (DCD) has accounted for a nearly 10-fold increase in kidney donors from 1999 to 2008. Use of livers from DCD donors declined in 2008 to 2005 levels. Understanding health risks associated with the transplantation of organs from 'high-risk' donors has received increased scrutiny.

Comparative risk of impaired glucose metabolism associated with cyclosporine versus tacrolimus in the late posttransplant period

New onset diabetes after transplantation (NODAT) and impaired fasting glucose (IFG) are common in kidney transplant recipients (KTRs). Calcinuerin inhibitor (CNI) therapy is a causal risk factor. NODAT is associated with increased mortality and diminished graft survival. We studied the incidence of NODAT and IFG in KTRs before and after a medically indicated switch of CNI therapy from cyclosporine (CsA) to tacrolimus (Tac). The study population consisted of 704 nondiabetic KTRs. Of them, 171 underwent conversion from CsA to Tac (group I) and 533 remained on the CsA since transplantation (Group II). Time-dependent Cox regression and generalized estimating equations were used to account for sequential CNI exposure. NODAT and IFG occurred in 15.2% and 22.1% of group I subjects and 15.6% and 25.8% of group II subjects, respectively (p = 0.90 for NODAT and p = 0.38 for IFG). Accounting for equal follow-up time since conversion from CsA to Tac, the adjusted 5-year NODAT-free survival was 87.4% and 91.4% in group I and group II, respectively (p = 0.90). In conclusion, conversion to Tac, compared to continuous exposure to CsA, carries quantitatively similar risk of impaired glucose metabolism in KTRs in the late posttransplant period.

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.

Menstruation: knowledge, attitude and practices of students in Ile-Ife, Nigeria

This study investigated students' knowledge of, beliefs, attitude to and practices during menstruation. Data was collected from a sample of 200 students from Ile-Ife using the multi-stage sampling technique. Only 5% of respondents could correctly define menstruation. Materials used to manage menstruation include sanitary pad, pieces of cloths, toilet rolls, cotton wool, tampon and shoulder pad foam. Practices vary on menstruating and non-menstruating days with 11(39.3%) of the 28 practices classified as healthy, 6(21.43%) as potentially harmful and 11(39.3%) as uncertain. Three (21.43%) of the listed 14 beliefs and taboos are potentially health-promoting, 5(35.71%) are potentially not health-promoting while 6(42.86%) are potentially harmless. Menstruation is associated with restrictions in diet and social interaction with 8%, 20.5% and 5% seeing menstruation as abnormal, dirty and a disease respectively. Findings from this study would be helpful in planning educational programmes to correct misinformation and promote healthy practices among women during menstruation.

Hepatitis C antibody status and outcomes in renal transplant recipients

BACKGROUND

Hepatitis occurs frequently in patients with end-stage renal disease. In 1997, 0.7% of patients receiving a renal transplant were positive for hepatitis C antibodies. Concern has been raised as to whether these patients are at an increased mortality risk after renal transplantation compared with patients who are hepatitis C antibody negative. To help answer this question, we analyzed data from the United States Renal Data System from October of 1988 through June of 1998.

METHODS

Primary study endpoints were patient death and death censored graft loss. Secondary study endpoints included cardiovascular, infectious, malignant, and infection-related death. Kaplan-Meier survival estimates as well as Cox proportional hazard models were used to evaluate the impact of hepatitis C antibody status on the study endpoints.

RESULTS

A total of 73,707 patients were analyzed. Patient survival by Kaplan-Meier analysis was higher in hepatitis C-positive patients, whereas death censored graft survival trended lower in the very long term. By the Cox model, hepatitis C-positive adjusted patient survival is slightly superior to that of hepatitis C-negative patients.

CONCLUSIONS

Renal transplant recipients who are hepatitis C antibody positive do not have an increased risk of death after transplantation compared with hepatitis C-negative recipients. The current policy of transplanting hepatitis C-positive patients without active liver disease seems to incur no excess mortality risk.

Posttransplant bone disease: a case illustrating dramatic improvements in bone density with vitamin D replacement therapy

Although bisphosponates are proposed as first-line treatment for posttransplant bone disease they are not optimal in all situations. A kidney transplant recipient developed hypercalcemia from mobilization of extraskeletal calcium. He had low serum parathyroid hormone and vitamin D; high calcium excretion; and normal calcium intake. Bone biopsy revealed severe osteomalacia. Bisphosphonates, used in the early treatment of acute hypercalcemia, were not indicated to treat osteomalacia. However, over several months serum calcium declined sufficiently to allow treatment of the bone disease with oral calcitriol. Dual-energy radiographic absorptiometry over the next 2 years documented dramatic improvements in bone density (percent of young-normal controls) : from 63 to 85%, at the lumbar spine; from 38 to 67%, at the femoral neck. This response to treatment could not have been achieved with an antiresorptive strategy. Optimal management of posttransplant bone disease requires a diagnostic approach, which considers all plausible contributing factors.

Excess risk of renal allograft loss associated with cigarette smoking

BACKGROUND

Cigarette smoking contributes to a number of health-related problems, but its impact on renal transplant survival beyond accelerated patient death is unclear.

METHODS

We performed a cohort study of 645 adult renal allograft recipients from 1985 to 1995 to evaluate the relationship between smoking and graft outcome.

RESULTS

Twenty-four percent of recipients (156/645) were smokers at the time of transplant evaluation. Of these, 90% continued to smoke after transplantation. Pretransplant smoking was significantly associated with reduced overall graft and death-censored graft survival. Patients who were smokers at the time of pretransplant evaluation had kidney graft survival of 84%, 65%, and 48% at 1, 5, and 10 years, respectively, compared with graft survival in nonsmokers of 88%, 78%, and 62% (P=0.007). Pretransplant smoking adversely affected death-censored graft survival in recipients of cadaveric (P=0.02) and of living donor kidneys (P=0.02). Reduced graft survival in pretransplant smokers could not be accounted for by differences in rejection (64% vs. 61%, P=0.35). In a multivariate analysis, pretransplant smoking was associated with a relative risk of 2.3 for graft loss. Among patients with a smoking history before transplantation, death-censored graft survival was significantly higher for those who quit smoking before transplant evaluation.

CONCLUSIONS

Cigarette smoking before kidney transplantation contributes significantly to allograft loss. The effect of smoking on graft outcome is not explained by increases in rejection or patient death. Smoking cessation before renal transplantation has beneficial effects on graft survival. These effects should be emphasized to patients with end-stage renal disease who are considering renal transplantation.

Exponentially increased risk of infectious death in older renal transplant recipients

BACKGROUND

The benefit of renal transplantation for patients with end-stage renal disease (ESRD) has been well documented. This benefit is seen throughout all age ranges of patients. However, it has been documented that older renal transplant recipients are at increased risk for death because of infectious causes when compared with younger recipients. The present study addresses whether this increased risk merely parallels an age-related increase in infectious mortality or is reflective of a particular vulnerability in older renal transplant recipients.

METHODS

Patients wait-listed and transplanted between 1988 and 1997 were analyzed utilizing the United States Renal Data System (USRDS) database. The primary study end point was patient death secondary to infection. Secondary end points included death secondary to cardiovascular cause and malignancy. Cox-proportional hazard models were utilized with all pertinent variables.

RESULTS

Death related to infectious cause increased exponentially in transplanted patients with increasing age (slope = 2.90.34x), while it increased linearly (slope = 1.9x + 8.6) with increasing age for those patients on the waiting list. Overall mortality increases with age were equal between the wait-listed and transplanted groups.

CONCLUSIONS

The overall survival benefit of transplantation is maintained in the older age groups. However, renal transplantation is associated with an increased risk for infectious death beyond the expected age-related increased risk in patients on the renal transplant waiting list. This may have an impact on future immunosuppressive regimens in this population.

Renal transplantation at the University of Michigan 1964 to 1999

The Michigan Kidney Transplant Program has existed for 35 years. Outcomes have improved dramatically as the one-year survival of cadaver kidney grafts increased from 25% to 85-90%. Patient deaths in the first year are now uncommon. Indications for renal transplantation have been extended to infants, the elderly, diabetics and to patients with other significant health problems who would not have been candidates in the past. Chronic administration of large doses of corticosteroids is no longer necessary and the associated morbidity is largely avoided. Improvements in immunosuppression, especially the introduction of cyclosporine, account for much of this progress. With success has come increasing demand. Unfortunately, the gap between the number of available donor kidneys and the number of patients listed for a cadaver transplant continues to increase rather than diminish. Greater acceptance of volunteer donation, as has occurred in our own program, will help to reduce this shortage. If the past forecasts the future, we can anticipate extraordinary advances during the next 35 years.

Interaction of mycophenolate mofetil and HLA matching on renal allograft survival

INTRODUCTION

The importance of HLA matching for renal transplantation outcomes has been appreciated for several decades. It has been hypothesized that as pharmacologic immunosuppression becomes stronger and more specific, the impact of HLA matching may be vanishing. Mycophenolate Mofetil (MMF) has been demonstrated to both decrease acute rejection and improve three-year graft survival. It is possible that with new immunosuppressive regimens containing MMF the relative effect of HLA matching may be altered. To determine the relative impact of HLA matching in patients on MMF we undertook an analysis of the United States Renal Transplant Data Registry (USRDS).

METHODS

All primary, solitary renal transplants registered at the USRDS between January 1995 and June 1997, on initial immunosuppression that included either MMF or AZA were followed until June 1998. Primary study end points were graft and patient survival. Kaplan-Meier analysis was performed to compare AZA vs. MMF treated patients by HLA mismatch. Cox proportional hazard models were used to investigate the interaction between HLA mismatch and AZA versus MMF therapy on the study endpoints. All multivariate analyses were corrected for 13 potential confounding pretransplant variables including intention to treat immunosuppression.

RESULTS

A total of 19,675 patients were analyzed (8,459 on MMF and 11,216 on AZA). Overall three year graft survival was higher in the MMF group when compared to the AZA group (87% vs. 84% respectively P<0.001). For both AZA and MMF three-year graft survival improved with fewer HLA donor-recipient mismatches. Comparing zero antigen mismatches to six antigen mismatches, the relative improvement was comparable for both patients on AZA (92.4% vs. 80.6%) and MMF (95.2% vs. 82.9%). By Cox proportional hazard model the relative risk for graft loss decreased significantly in both the AZA and MMF treated patients with increased HLA matching.

CONCLUSION

The use of MMF does not obviate the benefits of HLA matching, while HLA matching does not minimize the benefits of MMF on long term graft survival. Our study would suggest that HLA matching and MMF therapy are additive factors in decreasing the risk for renal allograft loss.

Gender differences in the risk for chronic renal allograft failure

BACKGROUND

Despite the known differences in immunological reactivity between males and females, no differences in graft survival have been described among renal transplant recipients with regard to gender. To address this paradox, we analyzed data from 73,477 primary renal transplants collected in the US Renal Data System database.

METHODS

Logistic regression and Cox proportional hazard models were used to investigate the primary study end points, graft loss secondary to acute rejection (AR) or chronic allograft failure (CAF). CAF was defined as graft loss beyond 6 months, not attributable to death, recurrent disease, acute rejection, thrombosis, infection, noncompliance, or technical problems. The models adjusted for 15 covariates including immunosuppressive regimen, and donor and recipient characteristics.

RESULTS

The overall 8-year graft and patient survivals were significantly better in female renal transplant recipients compared with male recipients. However graft survival censored for death was not significantly different by gender. By multivariate analysis, females had a 10% increased odds of AR (OR=1.10, CI 1.02-1.12), but conversely a 10% lower risk of graft loss secondary to CAF (RR=0.9, CI 0.85-0.96). The risk for CAF increased significantly with increasing age for both males and females, but this effect was greater for males than for females (P<0.001).

CONCLUSION

Although female renal transplant recipients have a similar death censored graft survival compared with males, there are important differences in immunological behavior. Females have a higher risk of AR while having a decreased risk of graft loss secondary to CAF.

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.

Increased impact of acute rejection on chronic allograft failure in recent era

BACKGROUND

Acute rejection (AR) remains a major risk factor for the development of chronic renal allograft failure (CAF), which is a major cause of late graft loss. With the introduction of several newer immunosuppressive agents (e.g., mycophenolate mofetil, tacrolimus and neoral) acute rejection rates have been steadily decreasing. However, the incidence of CAF has not decreased as dramatically as the incidence of acute rejection. One possible explanation is that the impact of AR on CAF is changing. The goal of this study was to analyze the relative impact of AR era on the development of CAF.

METHODS

We evaluated 63,045 primary renal transplant recipients reported to the USRDS from 1988 to 1997. CAF was defined as graft loss after 6 months posttransplantation, censored for death, acute rejection, thrombosis, infection, surgical complications, or recurrent disease. A Cox proportional hazard model correcting for 15 possible confounding factors evaluated the relative impact of AR on CAF. The era effect (years 1988-1989, 1990-1991, 1992-1993, 1994-1995 and 1996-1997) was evaluated by an era versus AR interaction term.

RESULTS

An AR episode within the first 6 months after transplantation was the most important risk factor for subsequent CAF (RR=2.4, CI 2.3-2.5). Compared with the reference group (1988-89 with no rejection), having an AR episode in 1988-89, 1990-1991, 1992-1993, 1994-1995, and 1996-1997, conferred a 1.67, 2.35, 3.4, 4.98 and 5.2-fold relative risk for the subsequent development of CAF (P<0.001).

CONCLUSIONS

Independently of known confounding variables, the impact of AR on CAF has significantly increased from 1988 to 1997. This effect may in part explain the relative lack of improvements in long term renal allograft survival, despite a decline in AR rates.

The effect of Daclizumab in a high-risk renal transplant population

INTRODUCTION

African-American (AA) renal transplant recipients have a higher incidence of acute rejection when compared to Caucasian renal transplant recipients. This higher rejection rate holds true even with the addition of several of the newer immunosuppressive agents (e.g. mycophenolate mofetil (MMF) and Rapamycin). Acute rejection rates among Hispanic (H) renal transplant recipients are higher in some settings, while lower or the same as in Caucasians in other settings. IL-2 receptor antibodies have been shown to decrease rejection rates when added to a regimen of cyclosporine (CsA), azathioprine and prednisone. Limited data are available on these agents in conjunction with triple CsA, MMF and prednisone therapy, particularly in higher risk group patients. We studied the effect of the addition of the IL-2 receptor antibody Daclizumab to a CsA, MMF, prednisone regimen in a group of African American and high-risk Hispanic renal transplant recipients.

METHODS

This was a non-randomized, prospective study. A total of 49 renal transplant recipients (29 African American and 20 Hispanic) were studied and followed. A simultaneous cohort of 56 (31 African-American and 25 Hispanic) renal transplant recipients receiving CsA, MMF and prednisone with no standard induction agent served as the control group. The study cohort received the same regimen with the addition of Daclizumab at 1 mg/kg for five doses over 10 wk. Multivariate analysis was performed to isolate independent factors influencing the study's results.

RESULTS

A total of 56 patients in the control group and 49 patients in the Daclizumab group received an average follow-up of 17.1 +/- 6.9 and 12.7 +/- 5.1 months, respectively. Acute rejection rates were lower in the Daclizumab group as compared to the control group 26.4% versus 49.3% per patient years, respectively. A total of eight recurrent rejections in 6 patients occurred in the control group and none in the Daclizumab arm. Graft loss at this follow-up was no different between the groups.

CONCLUSION

The addition of Daclizumab to a regimen of CsA, MMF and prednisone decreases acute rejection episodes in a high-risk group of African American and Hispanic renal transplant recipients.

Racial disparities in access to simultaneous pancreas-kidney transplantation in the United States

The purpose of our study is to assess the extent of racial differences in the access to simultaneous pancreas-kidney (SPK) transplantation and evaluate the potential influence of socioeconomic factors on access to transplantation. We performed a retrospective analysis of the US Renal Data System and United Network for Organ Sharing data on all patients with end-stage renal disease (ESRD) due to diabetes mellitus from 1988 to 1996 (n = 562, 814), including all dialysis, wait list, and transplant patients. Racial differences in incidence, prevalence, insurance coverage, employment status, and transplantation rates were calculated. Caucasians had the highest prevalence of ESRD caused by type 1 diabetes (73%), followed by blacks (22%), Hispanics (3%), Native Americans (2%), and others (<1%). Both blacks and Native Americans increased their annual incidence of ESRD caused by insulin-dependent diabetes mellitus by 10% compared with only a 3.5% increase in Caucasians, whereas incidence rates increased annually by almost 8% for both blacks and Native Americans compared with a 3% increase for Caucasians. However, Caucasians received 92% of all SPK transplants, whereas all other racial groups combined received a disproportionate minority of the remaining transplants. Lack of private insurance and unemployment status were associated with annual changes in both incidence of ESRD caused by type 1 diabetes and SPK transplant rates. In conclusion, we observed striking racial disparities for access to SPK transplantation in the United States today, which may be related to employment status, access to private insurance, and subsequent health care. Our preliminary data support current efforts to encourage Medicare and Medicaid coverage for all patients requiring SPK transplantation regardless of racial or financial status.

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.

Mycophenolate mofetil reduces late renal allograft loss independent of acute rejection

BACKGROUND

Mycophenolate Mofetil (MMF) has been shown to significantly decrease the number of acute rejection episodes in renal transplant recipients during the 1st year. A beneficial effect of MMF on long-term graft survival has been more difficult to demonstrate. This beneficial effect has not been detected, despite the impact of acute rejection on the development of chronic allograft nephropathy and experimental evidence that MMF may have a salutary effect on chronic allograft nephropathy independent of that of rejection.

METHODS

Data on 66,774 renal transplant recipients from the U.S. renal transplant scientific registry were analyzed. Patients who received a solitary renal transplant between October 1, 1988 and June 30, 1997 were studied. The Cox proportional hazard regression was used to estimate relevant risk factors. Kaplan-Meier analysis was performed for censored graft survival.

RESULTS

MMF decreased the relative risk for development of chronic allograft failure (CAF) by 27% (risk ratio [RR] 0.73, P<0.001). This effect was independent of its outcome on acute rejection. Censored graft survival using MMF versus azathioprine was significantly improved by Kaplan-Meier analysis at 4 years (85.61% v. 81.9%). The effect of an acute rejection episode on the risk of developing CAF seems to be increasing over time (RR=1.9, 1988-91; RR=2.9, 1992-94; RR=3.7, 1995-97).

CONCLUSION

MMF therapy decreases the risk of developing CAF. This improvement is only partly caused by the decrease in the incidence of acute rejection observed with MMF; but, is also caused by an effect independent of acute rejection.

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.

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.

Prescription of twice-weekly hemodialysis in the USA

BACKGROUND/AIMS

The purpose of this study was to investigate the frequency and characteristics of two hemodialysis sessions/week, to identify factors which influence or predict this prescription, and to examine the outcomes of patients receiving hemodialysis two times/week as compared to the more common treatment of three times/week.

METHODS

Data from a national sample of 15,067 adult hemodialysis patients were utilized to compare twice-weekly with thrice-weekly therapy by logistic regression.

RESULTS

Patients treated less than one year were more likely to be treated twice-weekly (6.1%) than patients on dialysis for one year or more (2.7%) (AOR = 1.49, p = 0.002). Treatment schedules also varied significantly by geographic region. Factors predictive of twice-weekly hemodialysis (p < 0.05) were older age, Caucasian race, female gender, higher serum albumin, lower serum creatinine levels, and lower body mass index. A higher estimated renal function at the start of ESRD was also predictive of a twice-weekly schedule among incident patients (AOR = 1.05, p = 0.05). In addition, Cox-adjusted survival analysis indicated a lower mortality risk (RR = 0.76, p = 0. 02) for twice-weekly hemodialysis compared to thrice-weekly among prevalent patients. For incident patients, however, the results were not significant when adjusted for GFR at ESRD onset (RR = 0.85, p = 0.31).

CONCLUSION

Geographic differences in prescribed treatment remained unexplained by measured characteristics. The survival advantage associated with twice-weekly hemodialysis is likely to be related to patient selection and greater residual renal function.

Comparison of mortality in all patients on dialysis, patients on dialysis awaiting transplantation, and recipients of a first cadaveric transplant

BACKGROUND AND METHODS

The extent to which renal allotransplantation - as compared with long-term dialysis - improves survival among patients with end-stage renal disease is controversial, because those selected for transplantation may have a lower base-line risk of death. In an attempt to distinguish the effects of patient selection from those of transplantation itself, we conducted a longitudinal study of mortality in 228,552 patients who were receiving long-term dialysis for end-stage renal disease. Of these patients, 46,164 were placed on a waiting list for transplantation, 23,275 of whom received a first cadaveric transplant between 1991 and 1997. The relative risk of death and survival were assessed with time-dependent nonproportional-hazards analysis, with adjustment for age, race, sex, cause of end-stage renal disease, geographic region, time from first treatment for end-stage renal disease to placement on the waiting list, and year of initial placement on the list.

RESULTS

Among the various subgroups, the standardized mortality ratio for the patients on dialysis who were awaiting transplantation (annual death rate, 6.3 per 100 patient-years) was 38 to 58 percent lower than that for all patients on dialysis (annual death rate, 16.1 per 100 patient-years). The relative risk of death during the first 2 weeks after transplantation was 2.8 times as high as that for patients on dialysis who had equal lengths of follow-up since placement on the waiting list, but at 18 months the risk was much lower (relative risk, 0.32; 95 percent confidence interval, 0.30 to 0.35; P<0.001). The likelihood of survival became equal in the two groups within 5 to 673 days after transplantation in all the subgroups of patients we examined. The long-term mortality rate was 48 to 82 percent lower among transplant recipients (annual death rate, 3.8 per 100 patient-years) than patients on the waiting list, with relatively larger benefits among patients who were 20 to 39 years old, white patients, and younger patients with diabetes.

CONCLUSIONS

Among patients with end-stage renal disease, healthier patients are placed on the waiting list for transplantation, and long-term survival is better among those on the waiting list who eventually undergo transplantation.

Comparison of mortality in all patients on dialysis, patients on dialysis awaiting transplantation, and recipients of a first cadaveric transplant

BACKGROUND AND METHODS

The extent to which renal allotransplantation - as compared with long-term dialysis - improves survival among patients with end-stage renal disease is controversial, because those selected for transplantation may have a lower base-line risk of death. In an attempt to distinguish the effects of patient selection from those of transplantation itself, we conducted a longitudinal study of mortality in 228,552 patients who were receiving long-term dialysis for end-stage renal disease. Of these patients, 46,164 were placed on a waiting list for transplantation, 23,275 of whom received a first cadaveric transplant between 1991 and 1997. The relative risk of death and survival were assessed with time-dependent nonproportional-hazards analysis, with adjustment for age, race, sex, cause of end-stage renal disease, geographic region, time from first treatment for end-stage renal disease to placement on the waiting list, and year of initial placement on the list.

RESULTS

Among the various subgroups, the standardized mortality ratio for the patients on dialysis who were awaiting transplantation (annual death rate, 6.3 per 100 patient-years) was 38 to 58 percent lower than that for all patients on dialysis (annual death rate, 16.1 per 100 patient-years). The relative risk of death during the first 2 weeks after transplantation was 2.8 times as high as that for patients on dialysis who had equal lengths of follow-up since placement on the waiting list, but at 18 months the risk was much lower (relative risk, 0.32; 95 percent confidence interval, 0.30 to 0.35; P<0.001). The likelihood of survival became equal in the two groups within 5 to 673 days after transplantation in all the subgroups of patients we examined. The long-term mortality rate was 48 to 82 percent lower among transplant recipients (annual death rate, 3.8 per 100 patient-years) than patients on the waiting list, with relatively larger benefits among patients who were 20 to 39 years old, white patients, and younger patients with diabetes.

CONCLUSIONS

Among patients with end-stage renal disease, healthier patients are placed on the waiting list for transplantation, and long-term survival is better among those on the waiting list who eventually undergo transplantation.

Dialysis modality and the risk of allograft thrombosis in adult renal transplant recipients

BACKGROUND

Renal vascular thrombosis (RVT) is a rare but catastrophic complication of renal transplantation. Although a plethora of risk factors has been identified, a large proportion of cases of RVT is unexplained. Uremic coagulopathy and dialysis modality may predispose to RVT. We investigated the impact of the pretransplant dialysis modality on the risk of RVT in adult renal transplant recipients.

METHODS

Renal transplant recipients (age 18 years or more) who were enrolled in the national registry between 1990 and 1996 (N = 84,513) were evaluated for RVT occurring within 30 days of transplantation. Each case was matched with two controls from the same transplant center and with the year of transplantation. The association between RVT and 18 factors was studied with multivariate conditional logistic regression.

RESULTS

Forty-nine percent of all cases of RVT (365 out of 743) occurred in repeat transplant recipients with an adjusted odds ratio (OR) of 5.72 compared with first transplants (P < 0.001). There were a significantly higher odds of RVT in peritoneal dialysis (PD)-compared with hemodialysis (HD)-treated patients (OR = 1.87, P = 0.001). Change in dialysis modality was an independent predictor of RVT: switching from HD to PD (OR = 3.59, P < 0.001) and from PD to HD (OR = 1.62, P = 0.047). Compared with primary transplant recipients on HD (OR = 1.00), the highest odds of RVT were in repeat transplant recipients treated with PD (OR = 12.95, P < 0.001) and HD (OR = 4.50, P < 0.001). Other independent predictors of RVT were preemptive transplantation, relatively young and old donor age, diabetes mellitus and systemic lupus erythematosus as causes of end-stage renal disease, recipient gender, and lower panel reactive antibody levels (PRAs).

CONCLUSIONS

The strongest risk factors for RVT were retransplantation and prior PD treatment. Prevention of RVT with perioperative anticoagulation should be studied in patients who have a constellation of the identified risk factors.

A practical approach to evaluate the potential donor pool and trends in cadaveric kidney donation

BACKGROUND

The potential supply of transplantable cadaver kidneys is often expressed as donors per million population (pmp), which ignores some essential factors governing organ donation.

METHODS

We performed a modeled analysis of kidney donor extraction rates by age, gender, race, cause of death, geographic region, and year in a cohort of evaluable deaths and actual cadaver donors between the ages of 1 and 65 years (1988-1993). Evaluable death was defined as an in-hospital death in patients between the ages of 1 and 65 years whose ICD-9-CM cause of death was not an obvious contraindication to kidney donation. The main outcome measures were the crude donation rate and an adjusted donor extraction rate (DER) per 1000 evaluable deaths.

RESULTS

A total of 1.4x10(6) in-hospital deaths produced 300,502 evaluable deaths and 20,575 actual donors. Between 1989 and 1993, DER increased from 61.1 to 75 per 1,000 evaluable deaths. DERs were highest among the youngest age groups, declining significantly with age from 405.0 to 16.7/1,000 evaluable deaths for age groups 1-10 and 56-65 years, respectively. There was a small difference in donors pmp between blacks and whites (15 vs. 18). In contrast, DER was seven times higher in whites compared with blacks (112.5 vs. 16.5/1,000 evaluable deaths; P<0.001). The crude donation rate (per 1,000 evaluable deaths) was high for stroke (604.8) and trauma-related deaths (230.6), resulting in highly efficient donor extraction from these deaths. Region-specific DERs ranged from 49.4 to 83/1,000 evaluable deaths and differed significantly from the corresponding donors pmp.

CONCLUSIONS

Estimating kidney donation relative to in-hospital evaluable deaths is a meaningful measure of organ procurement efficiency. Efforts to enhance cadaveric kidney donation should seek to understand and reduce the marked demographic and regional disparity in donor extraction rates.

Renal transplantation in end-stage sickle cell nephropathy

BACKGROUND

The role of renal transplantation as treatment for end-stage sickle cell nephropathy (SCN) has not been well established.

METHODS

We performed a comparative investigation of patient and allograft outcomes among age-matched African-American kidney transplant recipients with ESRD as a result of SCN (n=82) and all other causes (Other-ESRD, n=22,565).

RESULTS

The incidence of delayed graft function and predischarge acute rejection in SCN group (24% and 26%) was similar to that observed in the Other-ESRD group (29% and 27%). The mean discharge serum creatinine (SCr) was 2.7 (+/-2.5) mg/dl in the SCN recipients compared to 3.0 (+/-2.5) mg/dl in the Other-ESRD recipients (P=0.42). There was no difference in the 1-year cadaveric graft survival (SCN: 78% vs. Other-ESRD: 77%), and the multivariable adjusted 1-year risk of graft loss indicated no significant effect of SCN (relative risk [RR]=1.39, P=0.149). However, the 3-year cadaveric graft survival tended to be lower in the SCN group (48% vs. 60%, P=0.055) and their adjusted 3-year risk of graft loss was significantly greater (RR= 1.60, P=0.003). There was a trend toward improved survival in the SCN transplant recipients compared to their dialysis-treated, wait-listed counterparts (RR=0.14, P=0.056). In comparison to the Other-ESRD (RR=1.00), the adjusted mortality risk in the SCN group was higher both at 1 year (RR=2.95, P=0.001) and at 3 years (RR=2.82, P=0.0001) after renal transplantation.

CONCLUSIONS

The short-term renal allograft result in recipients with end-stage SCN was similar to that obtained in other causes of ESRD, but the long-term outcome was comparatively diminished. There was a trend toward better patient survival with renal transplantation relative to dialysis in end-stage SCN.

Long-term renal allograft survival: prognostic implication of the timing of acute rejection episodes

BACKGROUND

The timing of an acute rejection may have a variable impact on renal allograft survival. To determine whether the time of first acute transplant rejection (ATR) is an independent predictor of long-term allograft survival, we studied 31,600 first cadaveric renal transplants that were functional on the first transplant anniversary, from 217 U.S. centers.

METHODS

Transplant patients were divided into four groups according to the time to the first ATR: no rejection in year 1 (group I); predischarge ATR (group II); first ATR between discharge and month 6 (group III); and first ATR in months 7-12 (group IV).

RESULTS

Four-year allograft survival after year 1, estimated by a Cox proportional hazard model adjusting for 19 cofactors, was 78%, 72%, 69%, and 54% for groups I-IV, respectively (P<0.0001 for each comparison to group I). In those patients who had ATR episodes in more than one time period, later episodes were associated with worse long-term allograft survival, an observation that was independent of previous ATR episodes.

CONCLUSIONS

We conclude that late occurrence of a first acute rejection portends a worse prognosis for allograft survival after the first year. Later rejections, in combination with previous rejections, also lead to worse long-term allograft survival. Unlike early ATRs occurring in the setting of supervised immunosuppression, late occurring ATR may reflect inadequate immunosuppression from noncompliant behavior or may reflect disruption or lack of immune tolerance to the allograft. Efforts to minimize late transplant loss require a combination of strategies directed at both immunologic and behavioral factors.

Delayed graft function: risk factors and implications for renal allograft survival

Delayed graft function (DGF) may be associated with diminished kidney allograft survival. We studied the risk factors that lead to nonimmediate function of a renal allograft and the consequences of DGF on short- and long-term renal transplant survival. Data from the U.S. Renal Data System were used to measure the relationships among cold ischemia time, delayed graft function, acute rejection, and graft survival in 37,216 primary cadaveric renal transplants (1985-1992). These relationships were investigated using the unconditional logistic and Cox multivariate regression methods. Cold ischemia time was strongly associated with DGF, with a 23% increase in the risk of DGF for every 6 hr of cold ischemia (P<0.001). Acute transplant rejection occurred more frequently in grafts with delayed function (37% vs. 20%; odds ratio=2.25, P=0.001). DGF was independently predictive of 5-year graft loss (relative risk=1.53, P<0.001). The presence of both early acute rejection and DGF portended a dismal 5-year graft survival rate of 35%. Zero-HLA mismatch conferred a 10-15% improvement in 1- and 5-year graft survival regardless of early functional status of the allograft. However, the 5-year graft survival rate in HLA-mismatched kidneys without DGF was significantly higher than that of zero-mismatched kidneys with DGF (63% vs. 51%; P<0.001). DGF independently portends a significant reduction in short- and long-term graft survival. Delayed function and early rejection episodes exerted an additive adverse effect on allograft survival. The deleterious impact of delayed function is comparatively more severe than that of poor HLA matching.

Inferior outcome of two-haplotype matched renal transplants in blacks: role of early rejection

Acute rejection in the early post-transplant period is a major determinant of long-term outcome. A cohort analysis was performed to evaluate the race-specific incidence rates of early acute rejection episodes (AR) and delayed graft function (DGF) in Americans of African (blacks) and European (whites) descent (N = 2565) who received a 2-HM living-related donor (LRD) first kidney transplant between 1984 and 1992. After adjusting for center and recipient characteristics, blacks had a higher incidence of AR during the initial transplant hospitalization (blacks 13.2% vs. whites 7.4%, OR = 1.64, P = 0.02). DGF also occurred more frequently in blacks (unadjusted OR = 1.58, P = 0.07). Blacks with AR had significantly worse Cox-adjusted five year graft survival than similarly affected whites (blacks 50% vs. whites 76%, P < 0.01). We conclude that failure to take immunosuppressive medications cannot be implicated as a cause of the higher incidence of AR during the initial transplant hospitalization in black kidney transplant recipients. The excess risk of AR in blacks may reflect previously reported intrinsic differences in immune responsiveness and/or pharmacokinetics of immunosuppressive agents. The profound deleterious effect of AR appears to be largely responsible for the accelerated rate of late graft loss in African Americans.

Relative impact of donor type on renal allograft survival in black and white recipients

Renal allograft survival of organs from living-related donors (LRDs) is superior to that of organs from cadaveric donors (CAD). Allograft survival rates are lower in black recipients of both CAD and LRD transplants compared with recipients of other races. It is not known whether the superior donor effect of LRD varies between races. We investigated the graft survival outcome of first renal transplants performed in the United States in 1986 and 1989 to determine whether the donor effect differs between black and white recipients. A measurement of "donor type effect" is introduced. There were 7,002 and 7,307 first renal transplants in 1986 and 1989, respectively, for which allograft survival data were available from the United States Renal Data Systems. Both black and white recipients showed a greater than 50% reduction in the risk of allograft loss at all the points studied up to 5 years posttransplant when LRD was chosen over CAD transplantation. A measurement of donor type effect indicates that graft loss is reduced by 7 to 21 percentage points at 1 and 5 years posttransplant. The donor type effect is proportionally equal in both races. Therefore, kidney donation from living relatives as a first transplant should be encouraged for all medically suitable end-stage renal disease patients as a means of improving outcome and reducing CAD transplantation waiting time for patients in whom LRD transplants cannot be performed.