Hospitalized avascular necrosis after renal transplantation in the United States

BACKGROUND: The national incidence of and risk factors for hospitalized avascular necrosis (AVN) in renal transplant recipients has not been reported. METHODS: This historical cohort study consisted of 42,096 renal transplant recipients enrolled in the United States Renal Data System (USRDS) between 1 July 1994 and 30 June 1998. The data source was USRDS files through May 2000. Associations with hospitalizations for a primary diagnosis of AVN (ICD-9 codes 733.4x) within three years after renal transplant were assessed in an intention-to-treat design by Cox regression analysis. RESULTS: Recipients had a cumulative incidence of 7.1 episodes/1000 person-years from 1994 to 1998. The two-year incidence of AVN did not change significantly over time. Eighty-nine percent of the cases of AVN were due to AVN of the hip (733.42) and 60.2% of patients with AVN underwent total hip arthroplasty (THA); these percentages did not change significantly over time. In the Cox regression analysis, an earlier year of transplant, African American race [adjusted hazard ratio (AHR), 1.65, 95% confidence interval (CI) 1.33 to 2.03], allograft rejection (AHR 1.67, 95% CI 1.35 to 2.07), peritoneal dialysis (vs. hemodialysis; AHR 1.44, 95% CI 1.15 to 1.81), and diabetes (AHR 0.41, 95% CI 0.27 to 0.64) were the only factors independently associated with hospitalizations for AVN. CONCLUSIONS: The incidence of AVN did not decline significantly over time in the renal transplant population. Patients with allograft rejection, African American race, peritoneal dialysis and earlier date of transplant were at the highest risk of AVN, while diabetic recipients were at a decreased risk.     

Hospitalizations for bacterial endocarditis after renal transplantation in the United States.

PURPOSE: The national rate of and risk factors for bacterial endocarditis in renal transplant recipients has not been reported. METHODS: Retrospective registry study of 33,479 renal transplant recipients in the United States Renal Data System (USRDS) between 1 July 1994 and 30 June 1997. Hospitalizations for a primary diagnosis of bacterial endocarditis (ICD-9 codes 421.x) within three years after renal transplant were assessed. RESULTS: Renal transplant recipients had an unadjusted incidence ratio for endocarditis of 7.84 (95% confidence interval 4.72-13.25) in 1996. In multivariate analysis, a history of hospitalization for valvular heart disease (adjusted odds ratio (AOR), 25.81, 95% confidence interval 11.28-59.07), graft loss (AOR, 2.81, 95% CI 1.34-5.09), and increased duration of dialysis prior to transplantation were independently associated with hospitalizations for bacterial endocarditis after transplantation. Hospitalization for endocarditis was associated with increased patient mortality in Cox Regression analysis, hazard ratio 4.79, 95% CI 2.97-6.76. CONCLUSIONS: The overall incidence of bacterial endocarditis was much greater in renal transplant recipients than in the general population, although it is still relatively infrequent. Independent risk factors for bacterial endocarditis in the renal transplant recipients were identified, the most significant of which was valvular heart disease. Endocarditis substantially impacts renal transplant recipient survival.     

Hospitalizations for bacterial septicemia after renal transplantation in the united states

BACKGROUND: It is common belief in the transplant community that rates of septicemia in transplant recipients have declined, but this has not been studied in a national population. METHODS: Therefore, 33,479 renal transplant recipients in the United States Renal Data System from July 1, 1994 to June 30, 1997 were analyzed in a retrospective registry study of the incidence, associated factors, and mortality of hospitalizations with a primary discharge diagnosis of septicemia (ICD9 Code 038.x). RESULTS: Renal transplant recipients had an adjusted incidence ratio of hospitalizations for septicemia of 41.52 (95% CI 35.45-48.96) compared to the general population. Hospitalizations for septicemia were most commonly associated with urinary tract infection as a secondary diagnosis (30.6%). In multivariate analysis, diabetes and urologic disease, female gender, delayed graft function, rejection, and pre-transplant dialysis, but not induction antibody therapy, were associated with hospitalizations for septicemia. Recipients hospitalized for septicemia had a mean patient survival of 9.03 years (95% CI 7.42-10.63) compared to 15.73 years (95% CI 14.77-16.69) for all other recipients. CONCLUSIONS: Even in the modern era, renal transplant recipients remain at high risk for hospitalizations for septicemia, which are associated with substantially decreased patient survival. Newly identified risks in this population were female recipients and pre-transplant dialysis.     

Hospitalizations for bacterial pneumonia after renal transplantation in the United States

PURPOSE: Bacterial pneumonia has been cited as the leading cause of infectious death in renal transplant recipients but has not been studied in a national transplant population. SUBJECT AND METHODS: Retrospective analysis of the incidence, risk factors and mortality of hospitalized bacterial pneumonia (ICD9 Code 481.x486.x) for 33,479 renal transplant recipients in the United States Renal Data System transplanted from 1 July 1994-30 June 1997. RESULTS: Among all transplant recipients, 4.7% were hospitalized for a primary discharge diagnosis of pneumonia in the study period (2.86 episodes per 100 person years). 9.9% had bronchoscopy and 4.8% had open lung biopsy. A specific etiology was not identified in 72.5% of patients. The hospitalization rate for pneumonia and hazard for mortality due to hospitalized pneumonia were both constant over time. In logistic regression analysis, pneumonia prior to transplant (odds ratio 1.73, 95% confidence interval, 1.32-2.26), older recipient age, diabetes, delayed graft function, rejection (occurring at any time after transplant during the time of the study), duration of pre-transplant dialysis, and positive recipient cytomegalovirus serology were associated with pneumonia. In Cox Regression, hospitalization for pneumonia was associated with greater risk of mortality (hazard ratio 1.64, 95% CI, 1.42-1.89). CONCLUSIONS: Renal transplant recipients with a previous history of pneumonia are at increased risk for subsequent pneumonia, which is associated with substantially decreased patient survival. Given the low rate of specific etiologies identified in this study, invasive diagnosis may be underutilized in this population.     

Hospitalizations for Total Hip Arthroplasty after Renal Transplantation in the United States

The national incidence of and factors associated with total hip arthroplasty in renal transplant recipients has not been reported. We conducted an historical cohort study of 42096 renal transplant recipients in the United States between 1 July 1994 and 30 June 1998. Primary outcomes were associations with hospitalizations for a primary discharge code of total hip arthroplasty (ICD9 procedure code 81.51x) within 3 years after renal transplant using Cox regression. Renal transplant recipients had a cumulative incidence of total hip arthroplasty of 5.1 episodes/1000 person-years, which is 5-8 times higher than reported in the general population. Avascular necrosis of the hip was the most frequent primary diagnosis associated with total hip arthroplasty in this population (72% of cases). Repeat surgeries were performed in 27% of patients with avascular necrosis, vs. 15% with other diagnoses. Total hip arthroplasty was more frequent in transplant recipients who were older, African American, or who experienced allograft rejection. Mortality after total hip arthroplasty was 0.21% at 30 days and 15% at 3 years, similar to the mortality of all transplant recipients. The most common indication for total hip arthroplasty after renal transplant is avascular necrosis of the hip, in contrast to the general population. Although repeat surgeries are common, total hip arthroplasty is well tolerated and is not associated with increased mortality in this population.     

Death in the first year after kidney transplantation: implications for patients on the transplant waiting list

BACKGROUND: As the kidney transplant waiting list continues to expand, maintaining the medical fitness of transplant candidates will become increasingly difficult. METHODS: To identify patients who are at greatest risk during the wait-list period, we performed a Cox regression analysis to determine risk factors for mortality in the first posttransplantation year among 23,546 adult first kidney transplant recipients recorded in the United States Renal Data System between January 1995 and September 1997. RESULTS: In this study population, 4.6% of the patients died in the first posttransplantation year, and cardiac causes were the leading cause (27%) of death. Patients with diabetes (hazard ratio [HR]=1.58; 95% confidence interval [CI], 1.39-1.80), peripheral vascular disease (HR=1.41; 95% CI, 1.11-1.80), or angina (HR=1.38; 95% CI, 1.15-1.65), and patients with a longer duration of end-stage renal disease (HR=1.06 per year; 95% CI, 1.04-1.09) had a higher risk for mortality. Additionally, patients with early acute rejection (HR=1.47; 95% CI, 1.23-1.76), delayed graft function (HR=1.46; 95% CI, 1.25-1.71), and a lower glomerular filtration rate after transplantation were also at increased risk for death within the first posttransplantation year. CONCLUSIONS: Patients with comorbid disease, patients with a long duration of end-stage renal disease, and potential recipients of organs at high risk for graft dysfunction should be carefully screened for medical complications before transplantation to achieve the most favorable outcomes. Alternate organ allocation strategies that facilitate patient assessment close to the time of transplantation or that prioritize high-risk patients may also improve outcomes.     

Hospitalized Atrial Fibrillation After Renal Transplantation in the United States

Renal transplant recipients have a high incidence of hypertension, a known risk factor for atrial fibrillation (AF), as well as factors that could increase their risk of AF. However, the incidence of, risk factors for, and mortality associated with AF after renal transplantation have not been reported. We present a historical cohort study of 39 628 renal transplant recipients in the United States Renal Data System between 1 July 1994 and 30 June 1998. Data source: USRDS files through May 2000. Associations with hospitalizations for a primary diagnosis of AF (ICD-9 codes 427.31) after renal transplant were assessed by Cox Regression analysis. Tacrolimus was not approved for use by the FDA during the time-frame of the study. The incidence of AF after renal transplantation was 5.8 episodes/1000 person-years. In Cox Regression analysis, recipients who were older age, experienced graft loss, rejection, had higher body mass index, renal failure due to hypertension, and cyclosporine use (vs. tacrolimus use) were associated with increased risk of hospitalized AF. Atrial fibrillation was not uncommon after renal transplantation, and was associated with increased risk of mortality, primarily from cardiovascular disease. The strongest risk factors for AF after renal transplantation were older age, allograft rejection, graft loss and obesity.     

Graft loss and acute coronary syndromes after renal transplantation in the United States

The impact of graft loss on acute coronary syndromes (ACS) after renal transplantation has not been studied in a national population. It was hypothesized that ACS might be more frequent after graft loss, as many of the benefits of a functioning allograft on metabolism and volume regulation would be lost. Data from the 2000 United States Renal Data System (USRDS) was used to conduct an historical cohort study of ACS in 14,237 patients who received renal transplants between April 1, 1995, and June 30, 1998, (followed until April 28, 2000) with valid information from CMS Form 2728, excluding patients with hospitalized ACS before renal transplant. Cox nonproportional regression models were used to calculate the time-dependent adjusted hazard ratio (AHR) of graft loss (censored for death) for time-to-first hospitalization for ACS (International Classification of Diseases 9th Modification Diagnosis Codes [ICD9] code 410.x or 411.x) occurring after transplant. The incidence of ACS was 12.1 per 1000 patient-years (PY) in patients after graft loss versus 6.5 per 1000 PY after transplantation (excluding patients with graft loss). As a time-dependent variable, graft loss had an AHR of 2.54 (95% confidence interval, 1.09 to 5.96; P = 0.031 by Cox regression). Other risk factors associated with ACS included diabetes, older recipient, and male recipient. Allograft rejection was NS. Renal transplant recipients share some of the risk factors for ACS with the general population. In addition, graft loss was identified as a unique risk factor for ACS in this population.     

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.     

Effect of Donor Factors on Early Graft Survival in Adult Cadaveric Renal Transplantation

Previous studies of the effect of donor factors on renal transplant outcomes have not tested the role of recipient body mass index, donor/recipient weight ratios and age matching, and other factors. We analyzed 20,309 adult (age 16 or older) recipients having solitary cadaveric renal transplants from adult donors from 1 July 1994 to 30 June 1998 in an historical cohort study (the 2000 United States Renal Data System) of death censored graft loss by the Cox proportional hazards models, which corrected for characteristics thought to affect outcomes. The only independently significant findings in Cox Regression analysis were a high donor/ recipient age ratio (> or = 1.10, e.g. a 55-year-old donor given to a recipient age 50years or younger, adjusted hazard ratio (AHR) 3.22, 95% confidence interval (CI) 2.36-4.39) and African American donor kidneys (AHR 1.64, 95% CI, 1.24-2.17). African American recipients and older donors were not at independently increased risk of graft failure in this model. Among donor factors, older donor kidneys given to younger recipients and donor African American kidneys were independently associated with graft loss in recipients of cadaver kidneys. The task for the transplant community should be to find the best means for managing all donor organs without discouraging organ donation.     

Effect of mycophenolate mofetil on long-term outcomes in African american renal transplant recipients

African American renal transplant recipients have poorer graft survival. A study using the United States Renal Data Registry documented an improvement in graft survival for patients who took mycophenolate mofetil (MMF) compared with azathioprine (AZA). This analysis did not address the impact of MMF on African American renal transplant recipients. The present study aimed to quantify potential beneficial effects of MMF therapy on long-term renal allograft survival in African Americans. With the use of the United States Renal Data Registry, all adult Caucasian and African American patients who had received a primary renal transplant between 1988 and 1997 were analyzed by Kaplan-Meier analysis and Cox proportional hazard models. Primary study end points were death with a functioning graft and graft failure censored for death. A total of 57,926 patients were studied. For African Americans, 3-yr patient survival was 96.3 versus 93.2% (P<0.001) for MMF and AZA, respectively. Three-yr death-censored graft survival for African Americans was 85.8 versus 75.1% (P<0.001) for MMF and AZA, respectively. For Caucasians, 3-yr patient survival was 97.3 versus 93.2% for MMF and AZA, respectively. Three-yr death-censored graft survival for Caucasians was 90.1 versus 86.4% (P<0.001) for MMF and AZA, respectively. By multivariate analysis, MMF was associated with a significant reduction in the relative risk for all study end points in African Americans. MMF therapy is associated with both improved patient and death-censored graft survival in African American renal transplant recipients. This benefit is comparable to the benefit of MMF in Caucasian renal transplant recipients.     

Is mycophenolate mofetil less safe than azathioprine in elderly renal transplant recipients?

BACKGROUND: Mycophenolate mofetil (MMF) is a potent immunosuppressive agent that has been shown to be superior to azathioprine in preventing early acute rejection in the general renal transplant population. However, it is uncertain whether these benefits also apply to older renal transplant recipients, who are known to be more susceptible to infectious complications and have considerably lower rates of rejection and immunological graft loss. METHODS: A retrospective analysis was undertaken of all elderly (> or =55 years old) renal transplant recipients who underwent renal transplantation at the Princess Alexandra Hospital (1994-2000) and received either MMF (n=60) or azathioprine (n=55) in combination with prednisolone and cyclosporin. Data were analyzed on an intention-to-treat basis using a multivariate Cox proportional hazards model. RESULTS: The azathioprine- and MMF-treated groups were well matched at baseline with respect to demographic characteristics, end-stage renal failure causes and transplant characteristics. Compared with the MMF cohort, azathioprine-treated patients experienced a shorter time to first rejection [hazard ratio (HR) 4.47, 95% CI 1.53-13.1, P<0.01]. However, azathioprine-treated patients were also less likely to develop opportunistic infections (HR 0.11, 95% CI 0.03-0.41, P=0.001). No differences were observed between the two groups with respect to hospitalization rates, intensive care admissions, hematological complications, or posttransplant malignancies. Actuarial 2-year survival rates for the azathioprine- and MMF-treated patients were 100 and 87%, respectively (P<0.001). The principal cause of death in the MMF cohort was infection. Using a multivariate Cox regression analysis of patient survival, an adjusted hazard ratio of 0.01 (95% CI 0.001-0.08, P=0.001) was calculated in favor of azathioprine. Overall graft survival also tended to be better in patients receiving azathioprine (HR 0.27, 95% CI 0.06-1.33, P=0.11), CONCLUSIONS: In elderly renal transplant recipients, the combination of MMF, cyclosporin, and prednisolone appears to result in a worse outcome compared with the less potent combination of azathioprine, cyclosporin, and prednisolone. Future prospective studies need to specifically evaluate the risk/benefit ratios of newer, more potent immunosuppressive protocols, such as MMF-based regimens, in this important and sizeable patient subgroup.     

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.     

Risk factors for pulmonary embolism in chronic dialysis patients

BACKGROUND: Risk factors for pulmonary embolism (PE) in end stage renal disease (ESRD) patients have not been studied in a large population. METHODS: 375,152 patients in the United States Renal Data System initiated on dialysis between 1 January 1992 and 30 June 1997 were analyzed in an historical cohort study of hospitalized PE (ICD9 Code 415.1x) occurring prior to receipt of renal transplant. Cox regression models were used to analyze risk factors for PE in dialysis. Dialysis modality was analyzed in an intention to treat fashion, thus patients who changed modalities later were considered to have remained on the same modality. RESULTS: The incidence of pulmonary embolism did not increase over time. Independent risk factors for hospitalizations for PE were similar to those in the general population (older age, females, systemic lupus erythematosus, lower risk for Asians) with the addition of peritoneal dialysis (vs. hemodialysis, adjusted odds ratio 1.56, 95% CI 1.15-2.13), polycystic kidney disease, and congestive heart failure. Notably, in Cox regression analysis, no relation was seen with baseline laboratory results (hematocrit, serum albumin, serum creatinine) or comorbidity (except congestive heart failure) and PE risk. Dialysis patients with PE had increased mortality (hazard ratio 1.20, 95% confidence interval 1.08-1.33). CONCLUSIONS: The incidence of PE did not increase significantly in ESRD patients from 1992-1997. PE were associated with increased mortality. Peritoneal dialysis patients may have higher risk of PE than hemodialysis patients, and other high-risk groups were identified.     

Hospitalizations for bacterial endocarditis after initiation of chronic dialysis in the United States

AIMS: Bacterial endocarditis is a significant cause of morbidity and mortality but has not been studied in a national population of end-stage renal disease patients. METHODS: 327,993 dialysis patients in the United States Renal Data System initiated from 1 January 1992 to 30 June 1997 were analyzed in a historical cohort study of hospitalized bacterial endocarditis (ENDO, ICD9 Code 421.x). Renal transplant recipients were excluded. RESULTS: Hemodialysis patients had an age-adjusted incidence ratio for ENDO of 17.86 (95% confidence interval, 6.62-48.90) and peritoneal dialysis patients 10.54 (95% CI, 0.71- 158.13, not statistically significant) compared to the general population in 1996 (the National Hospital Discharge Survey). 6.1% of patients with ENDO underwent valve replacement surgery. In multivariate analysis, hemodialysis (vs. peritoneal dialysis), earlier year of dialysis, cardiac disease, and lower serum creatinine and albumin were associated with increased risk of ENDO. In Cox regression analysis, patients with ENDO had increased mortality, relative risk 1.48 (95% CI 1.45-1.73). CONCLUSIONS: Patients on chronic dialysis were at increased risk for ENDO compared to the general population. The risk for peritoneal dialysis patients was not statistically significant, possibly due to the smaller numbers of patients on this modality. Hemodialysis (vs. peritoneal dialysis) and comorbidities were the strongest risk factors for ENDO identified.     

Risk factors for hospitalizations resulting from pulmonary embolism after renal transplantation in the United States.

BACKGROUND: Risk factors for pulmonary embolism (PE) have been identified in the general population but have not been studied in a national population of renal transplant recipients. METHODS: Therefore, 33,479 renal transplant recipients in the United States Renal Data System from 1 July 1994-30 June 1997 were analyzed in a historical cohort study of hospitalized PE (ICD9 Code 415.1x). HCFA form 2728 was used for comorbidities. RESULTS: Renal transplant recipients had an incidence of PE of 2.26 hospitalizations per 1000 patient years at risk. In multivariate analysis, polycystic kidney disease (adjusted odds ratio, 4.44, 95% confidence interval, 2.31-8.53), older recipient age, higher recipient weight, cadaveric donation, history of ischemic heart disease, and decreased serum albumin were associated with increased risk of PE. Body mass index and hemoglobin were not significant. Kidney-pancreas transplantation was also not significant. In Cox Regression analysis PE was associated with increased mortality (hazard ratio 2.06, 95% CI 1.34-3.18). CONCLUSIONS: The most important risk factors for PE in this population were polycystic kidney disease, advanced age and increased weight. The reasons for the increased risk of polycystic kidney disease remain to be determined but were independent of hematocrit level at initiation of end stage renal disease, and may result from venous compression. Prospective studies of anatomical and hemostatic changes after renal transplantation in recipients with polycystic kidney disease are warranted.     

Hospitalizations for fungal infections after initiation of chronic dialysis in the United States.

AIMS: Hospitalized fungal infections are reported frequently in renal transplant recipients and peritoneal dialysis patients, but the frequency of hospitalized fungal infections in dialysis patients has not been studied in a national population. METHODS: 327,993 dialysis patients in the United States Renal Data System initiated from January 1, 1992 to June 30, 1997 were analyzed in a retrospective registry study of fungal infections (based on ICD9 Coding). RESULTS: Dialysis patients had an age-adjusted incidence ratio for fungal infections of 9.80 (95% confidence interval (CI) 6.34-15.25)) compared to the general population in 1996 (the National Hospital Discharge Survey). Candidiasis accounted for 79% of all fungal infections, followed by cryptococcosis (6.0%) and coccidioidomycosis (4.1%). In multivariate analysis, fungal infections were associated with earlier year of dialysis, diabetes, female gender, decreased weight and serum creatinine at initiation of dialysis, chronic obstructive lung disease and AIDS. In Cox regression analysis the hazard ratio for mortality of fungal infections was 1.35 (95% CI 1.28-1.42). CONCLUSIONS: Dialysis patients were at increased risk for fungal infections compared to the general population, which substantially decreased patient survival. Female and diabetic patients were at increased risk for fungal infections. Although candidiasis was the dominant etiology of fungal infections, the frequency of cryptococcosis and coccidioidomycosis were higher than previously reported.     

Hospitalized Nephrolithiasis after Renal Transplantation in the United States

The national incidence of and risk factors for hospitalized nephrolithiasis (NEP) in renal transplant (RT) recipients has not been reported. We conducted a historical cohort study of 42 096 RT recipients in the United States Renal Data System between 1 July 1994 and 30 June 1998. The 1-year incidence of NEP (ICD-9 codes 592.x) after RT in 1997 was compared to the rate of NEP in the general population using the National Hospital Discharge Survey. Associations with time to hospitalizations for a primary diagnosis of nephrolithiasis were assessed by Cox Regression. NEP was uncommon after RT (104 cases per 100 000 person years in 1997). However, females, but not males, had a statistically significant increased risk of NEP compared to the general population (rate ratio for females, 2.84, 95% confidence interval, 2.35-3.58). Kidney stones were more common than ureteral stones, and percutaneous procedures were more common than ureteroscopy or extracorporeal shock wave lithotripsy (ESWL). The only risk factor identified for NEP was renal failure due to stone disease (only one case). NEP was uncommon after RT, but was still more common than in the general population. We identified differences in the presentation and management of NEP after RT in comparison to the general population.     

Hospitalizations for bacterial septicemia in patients with end stage renal disease due to diabetes on the renal transplant waiting list

The incidence and risk factors for hospitalizations for bacterial septicemia, a serious cause of morbidity and mortality in end stage renal disease (ESRD), have been studied separately for patients on chronic dialysis and after renal transplantation, but have not been compared directly. Using data from the USRDS, we studied 11,369 patients with ESRD due to diabetes enrolled on the renal and renal-pancreas transplant waiting list from 1 July 1994-30 June 1997. Cox non-proportional hazards regression models were used to calculate adjusted, time-dependent hazard ratios (HR) for time to hospitalization for bacterial septicemia (ICD9 Code 038.x). In Cox Regression analysis, renal transplantation was independently associated with a shorter time to bacterial septicemia (HR 1.22, 95% confidence interval, 1.05-1.40). In addition, renal transplantation was associated with a higher rate of sepsis due to gram-negative organisms (HR 3.32, 95% CI 2.614.23) and urinary tract infection (10.43, 95% CI 6.72-16.17) compared with patients still on the renal transplant waiting list. The relative risk of sepsis increased with time after renal transplantation. Renal transplantation was associated with a significantly higher risk and different spectrum of bacterial septicemia than maintenance dialysis, and the risk of sepsis did not decrease over time.     

The influence of pre-operative electrocardiographic abnormalities and cardiovascular risk factors on patient and graft survival following renal transplantation

Premature cardiovascular disease (CVD) is the leading cause of mortality and of graft loss in renal transplant recipients. However, the pattern of cardiovascular risk factors (specifically modifiable risk factors) is not well established and may be different from the general population. In this study we investigated the importance of electrocardiographic abnormalities and conventional cardiovascular risk factors present at the time of first renal transplantation in a longitudinal follow-up study of 515 patients. Overall, 45.8% were cigarette smokers, 13.0% were diabetic, 75.1% had "hypertension", 12.2% had symptoms of angina pectoris and 9.1% had a past history of myocardial infarction or stroke. Two thirds of ECG tracings were abnormal. 58.7% of men and 37.5% of women had left ventricular hypertrophy (LVH). Overall, 28.2% had simple LVH, 20.5% had LVH with repolarisation changes ('strain'). 434 patients had complete data for multivariate analyses of patient and graft survival. A Cox multivariate analysis of patient survival (patients whose graft failed were censored in the analysis) identified: age (hazard ratio 1.03/year), diabetes (2.72), smoking (1.81) and family history of premature CVD (2.17) as independent risk factors for patient survival. An abnormal ECG was also independently associated with outcome, with the exception of isolated left ventricular hypertrophy. Left ventricular hypertrophy with strain, or ischaemic changes were associated with adverse outcome with a hazard ratio of 1.96 and 3.30 respectively. A similar analysis of the determinants of graft survival (patients who died with a functioning graft were censored in the analysis) identified: acute rejection (hazard ratio 2.38), cigarette smoking (1.48) and age (1.04/year) as independent predictors of graft failure. These data demonstrate a high prevalence of ECG abnormalities and CV risk factors in renal transplant recipients. Moreover, ECG abnormalities and "conventional" cardiovascular risk factors are associated with poor graft and patient outcome and represent potentially remediable risk factors for renal transplant recipients.