The association of SBP with mortality in patients with stage 1-4 chronic kidney disease.

OBJECTIVES: Hypertension is a risk factor for chronic kidney disease (CKD) progression and mortality. However, the optimal blood pressure associated with decreased mortality in each stage of CKD remains uncertain. METHODS: In this retrospective cohort study, we included 13 414 individuals with CKD stages 1-4 from NHANES general population datasets from 1999 to 2004 followed to 31 December 2010. Multivariate analysis and Kaplan--Meier curves were used to assess SBP and risk factors associated with overall mortality in each CKD stage. RESULTS: In these individuals with death rates of 9, 12, 30 and 54% in baseline CKD stages 1 through 4, respectively, SBP less than 100 mmHg was associated with significantly increased mortality adjusted for age, sex and race in stages 2,3,4. After excluding less than 100 mmHg, as a continuous variable, higher SBP is associated with fully adjusted increased mortality risk in those on or not on antihypertensive medication (hazard ratio 1.006, P = 0.0006 and hazard ratio 1.006 per mmHg, P < 0.0001, respectively). In those on antihypertensive medication, SBP less than 100 mmHg or in each 20 mmHg categorical group more than 120 mmHg is associated with an adjusted risk of increased mortality. Increasing age, men, smoking, diabetes and comorbidities are associated with increased mortality risk. CONCLUSION: For patients with CKD stages 1-4, the divergence of SBP above or below 100-120 mmHg was found to be associated with higher all-cause mortality, especially in those patients on antihypertensive medication. These findings support the recent guideline of an optimal target goal SBP of 100-120 mmHg in patients with CKD stages 1-4.

Ferric Citrate Dosing in Iron Deficiency Anemia in Nondialysis-Dependent Chronic Kidney Disease.

INTRODUCTION: Ferric citrate (FC) is indicated as an oral iron replacement for iron deficiency anemia in adult patients with chronic kidney disease (CKD) not on dialysis. The recommended starting dose is one 1-g tablet three times daily (TID). This study investigated long-term efficacy and safety of different FC dosing regimens for treating anemia in nondialysis-dependent CKD (NDD-CKD). METHODS: In this phase 4, randomized, open-label, multicenter study, patients with anemia with NDD-CKD (estimated glomerular filtration rate, ≥20 mL/min and <60 mL/min) were randomized 1:1 to one FC tablet (1-g equivalent to 210 mg ferric iron) TID (3 g/day) or 2 tablets twice daily (BID; 4 g/day). At week 12, dosage was increased to 2 tablets TID (6 g/day) or 3 tablets BID (6 g/day) in patients whose hemoglobin (Hb) levels increased <0.5 g/dL or were <10 g/dL. Primary endpoint was mean change in Hb from baseline to week 24. RESULTS: Of 484 patients screened, 206 were randomized and 205 received FC. Mean (standard deviation) changes from baseline in Hb at week 24 were 0.77 (0.84) g/dL with FC TID 3 g/day and 0.70 (0.98) g/dL with FC BID 4 g/day. DISCUSSION/CONCLUSIONS: FC administered BID and TID for 48 weeks was safe and effective for treating anemia in this population, supporting potentially increased dosing flexibility.

Pre-transplant Social Adaptability Index and clinical outcomes in renal transplantation: The Swiss Transplant Cohort study.

BACKGROUND: The impact of pre-transplant social determinants of health on post-transplant outcomes remains understudied. In the United States, poor clinical outcomes are associated with underprivileged status, as assessed by the Social Adaptability Index (SAI), a composite score of education, employment status, marital status, household income, and substance abuse. Using data from the Swiss Transplant Cohort Study (STCS), we determined the SAI's predictive value regarding two post-transplant outcomes: all-cause mortality and return to dialysis. METHODS: Between 2012 and 2018, we included adult renal transplant patients (aged ≥ 18 years) with pre-transplant assessment SAI scores, calculated from a STCS Psychosocial Questionnaire. Time to all-cause mortality and return to dialysis were predicted using Cox regression. RESULTS: Of 1238 included patients (mean age: 53.8 ± 13.2 years; 37.9% female; median follow-up time: 4.4 years [IQR: 2.7]), 93 (7.5%) died and 57 (4.6%) returned to dialysis. The SAI's hazard ratio was 0.94 (95%CI: 0.88-1.01; p = .09) for mortality and 0.93 (95%CI: 0.85-1.02; p = .15) for return to dialysis. CONCLUSIONS: In contrast to most published studies on social deprivation, analysis of this Swiss sample detected no significant association between SAI score and mortality or return to dialysis.

Developing and testing models to predict mortality in the general population.

We have previously proposed an approach using information collected from published reports to generate prediction models. The goal of this project was to validate this technique to develop and test various prediction models. A risk indicator (R) is calculated as a linear combination of the hazard ratios for the following predictors: age, male gender, diabetes, albuminuria, and either CKD, CVD or both. We developed a linear and two exponential expressions to predict the probability of the outcome of 2-year mortality and compared to actual outcome in the target dataset from NHANES. The risk indicator demonstrated good performance with area under ROC curve of 0.84. The linear and two exponential expressions generated similar predictions in the lower categories of risk indicator (R ≤ 6). However, in the groups with higher R value, the linear expression tends to predict lower, and the exponential expressions higher, probabilities than the observed outcome. A Combined model which averaged the linear and logistic expressions was shown to approximate the actual outcome data the best. A simple technique (named Woodpecker™) allows derivation functional prediction models and risk stratification tools from reports of clinical outcome studies and their application to new populations by using only summary statistics of the new population.

Prediction Model and Risk Stratification Tool for Survival in Patients With CKD.

INTRODUCTION: Because chronic kidney disease (CKD) adversely affects survival, prediction of mortality risk should help to identify individuals requiring therapeutic intervention. The goal of this project was to construct and to validate a risk scoring system and prediction model of the probability of 2-year mortality in a CKD population. METHODS: We applied the Woodpecker approach to develop prediction equations using linear, exponential, and combined models. A risk indicator R on a scale of 0 to 10 was calculated as follows: starting with 0, add 0.048 for each year of age above 20, 0.45 for male sex, 0.49 for each stage of CKD over stage 2, 1.04 for proteinuria, 0.72 for smoking history, and 0.49 for each significant comorbidity up to 5. RESULTS: Using R to predict 2-year mortality, the model yielded an area under the receiver operating characterisic curve of 0.83 (95% confidence interval = 0.81-0.86) with 5062 subjects with CKD ≥stage 2 from a National Health and Nutrition Examination Survey cohort (1999-2004) having a 3.2% 2-year mortality. The combined expression offered results closest to most actual outcomes for the entire population and for each CKD stage. For those patients with higher risk (R ≥ 4-5, >5-6, and >6), the predicted 2-year mortality rates were 3.8%, 6.4%, and 13.0%, respectively, compared to observed mortality rates of 2.7%, 4.5%, and 13.3%. CONCLUSION: The risk stratification tool and prediction model of 2-year mortality demonstrated good performance and may be used in clinical practice to quantify the risk of death for individual patients with CKD.

The Survival Benefit of "Fistula First, Catheter Last" in Hemodialysis Is Primarily Due to Patient Factors.

Patients needing hemodialysis are advised to have arteriovenous fistulas rather than catheters because of significantly lower mortality rates. However, disparities in fistula placement raise the possibility that patient factors have a role in this apparent mortality benefit. We derived a cohort of 115,425 patients on incident hemodialysis ≥67 years old from the US Renal Data System with linked Medicare claims to identify the first predialysis vascular access placed. We compared mortality outcomes in patients initiating hemodialysis with a fistula placed first, a catheter after a fistula placed first failed, or a catheter placed first (n=90,517; reference group). Of 21,436 patients with a fistula placed first, 9794 initiated hemodialysis with that fistula, and 8230 initiated dialysis with a catheter after failed fistula placement. The fistula group had the lowest mortality over 58 months (hazard ratio, 0.50; 95% confidence interval, 0.48 to 0.52; P<0.001), with mortality rates at 6, 12, and 24 months after initiation of 9%, 17%, and 31%, respectively, compared with 32%, 46%, and 62%, respectively, in the catheter group. However, the group initiating hemodialysis with a catheter after failed fistula placement also had significantly lower mortality rates than the catheter group had over 58 months (hazard ratio, 0.66; 95% confidence interval, 0.64 to 0.68; P<0.001), with mortality rates of 15%, 25%, and 42% at 6, 12, and 24 months, respectively. Thus, patient factors affecting fistula placement, even when patients are hemodialyzed with a catheter instead, may explain at least two thirds of the mortality benefit observed in patients with a fistula.

Second vascular access after failure of the first fistula in the elderly
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BACKGROUND: In patients with failure of an initial arteriovenous fistula (AVF), a subsequent vascular access is needed before hemodialysis (HD) initiation. METHODS: To assess the optimal access strategy after a failed AVF, we linked data from the US Renal Data System with Medicare claims data identifying 21,436 patients ≥ 67 years old who started HD between January 1, 2005, and December 31, 2008, with an AVF placed as their first predialysis access. Of the 10,568 subjects whose AVF failed, 1,796 patients had an AVF placed as a second access predialysis (AVF2 group) and 399 patients had an arteriovenous graft placed as a second access predialysis (AVG2 group). Second access success was defined as HD initiation for the first HD session using this access avoiding need for a catheter. RESULTS: The mean age for AVF2 and AVG2 groups was 75.9 ± 6.0 and 75.9 ± 5.9 years with a significantly greater percentage of men and whites in the AVF2 group and women and blacks in the AVG2 group. Overall, 53% of AVF2 group initiated dialysis using AVF2, and 66% of AVG2 group started dialysis using AVG2 (p < 0.001). The following variables were found to be associated with AVF2 failure: female gender, peripheral vascular disease (PVD), interventional procedures, and the absence of pre-ESRD nephrology care. AVG2 failure was associated with white race, lower body mass index (BMI), and the absence of pre-ESRD (end-stage renal disease) nephrology care. CONCLUSION: Since the success rate to avoid the use of a catheter was significantly higher in the AVG2 group than in the AVF2 group, an AVG may be a preferable choice of second access in certain patients, especially in females, blacks and those with PVD.
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Practical prediction model for the risk of 2-year mortality of individuals in the general population.

This study proposed to validate a prediction model and risk-stratification tool of 2-year mortality rates of individuals in the general population suitable for office practice use. A risk indicator (R) derived from data in the literature was based on only 6 variables: to calculate R for an individual, starting with 0, for each year of age above 60, add 0.14; for a male, add 0.9; for diabetes mellitus, add 0.7; for albuminuria > 30 mg/g of creatinine, add 0.7; for stage ≥ 3 chronic kidney disease (CKD), add 0.9; for cardiovascular disease (CVD), add 1.4; or for both CKD and CVD, add 1.7. We developed a univariate logistic regression model predicting 2-year individual mortality rates. The National Health and Nutrition Examination Survey (NHANES) data set (1999-2004 with deaths through 2006) was used as the target for validation. These 12,515 subjects had a mean age of 48.9 ± 18.1 years, 48% males, 9.5% diabetes, 11.7% albuminuria, 6.8% CVD, 5.4% CKD, and 2.8% both CKD and CVD. Using the risk indicator R alone to predict mortality demonstrated good performance with area under the receiver operating characteristic (ROC) curve of 0.84. Dividing subjects into low-risk (R=0-1.0), low intermediate risk (R > 1.0-3.0), high intermediate risk (R > 3.0-5.0) or high-risk (R > 5.0) categories predicted 2-year mortality rates of 0.52%, 1.44%, 5.19% and 15.24%, respectively, by the prediction model compared with actual mortality rates of 0.29%, 2.48%, 5.13% and 13.40%, respectively. We have validated a model of risk stratification using easily identified clinical characteristics to predict 2-year mortality rates of individuals in the general population. The model demonstrated performance adequate for its potential use for clinical practice and research decisions.

Clinical issues in renal transplantation in the elderly.

Kidney transplantation is the best renal replacement therapy option and is superior to dialysis in elderly end-stage renal disease (ESRD) patients. Furthermore, the outcome of transplantation in the elderly is comparable to younger patients in terms of allograft survival. The exact nature of this phenomenon is not completely clear. As the elderly population continues to grow, it becomes more important to identify specific issues associated with kidney transplantation. In particular, elderly transplant recipients might have a lower chance of acute rejection as their immune systems seem to be less reactive. This might predispose elderly recipients to greater risk of post-transplant infectious complications or malignancies. Furthermore, due to differences in pharmacokinetics, elderly recipients might require lower doses of immunosuppressive medication. As the main cause of graft failure in the elderly is death with a functioning graft and also considering the scarcity of donor organs, it might make sense to recommend transplanting elderly recipients with extended criteria donor kidneys. This approach would balance shorter patient survival compared to younger recipients. In conclusion, old age should not preclude ESRD patients from kidney transplantation. However, specific differences that have to do with immunosuppression and other aspects of managing elderly transplant recipients should be considered.

Arteriovenous fistula placement in the elderly: when is the optimal time?

Arteriovenous fistula (AVF) is the preferred vascular access for hemodialysis (HD). However, many AVFs fail before starting dialysis. To assess the optimal time for AVF placement in the elderly, we linked data from the US Renal Data System with Medicare claims data to identify 17,511 patients ≥67 years old on incident HD who started dialysis between January 1, 2005, and December 31, 2008, with an AVF placed as the first predialysis access. AVF success was defined as dialysis initiation using the AVF, with time between AVF placement and dialysis start as our primary variable of interest. The mean age was 76.1±6.0 years, and 58.3% of subjects were men. Overall, 54.9% of subjects initiated dialysis using an AVF, and 45.1% of subjects used a catheter or graft. The success rate increased as time from AVF creation to HD initiation increased from 1-3 months (odds ratio [OR], 0.49; 95% confidence interval [95% CI], 0.44 to 0.53) to 3-6 months (OR, 0.93; 95% CI, 0.85 to 1.02) to 6-9 months (OR, 0.99; 95% CI, 0.88 to 1.11) but stabilized after that time. Furthermore, the number of interventional access procedures increased over time starting at 1-3 months, with a mean of 0.64 procedures/patient for AVFs created 6-9 months predialysis compared with 0.72 for AVFs created >12 months predialysis (P<0.001). Although limited by the observational nature of this study, our results suggest that placing an AVF >6-9 months predialysis in the elderly may not associate with a better AVF success rate.

The role of disparities and socioeconomic factors in access to kidney transplantation and its outcome.

BACKGROUND: Research focused on identifying vulnerable populations and revealing specific risk factors for barriers along the pathway from ESRD to kidney transplantation has been mostly descriptive and the causes of existing disparities remain unclear. However, several socio-economic factors that are associated with the access to and the outcome of the kidney transplantation have been identified. SUMMARY: While the presence of racial, gender, and geographic disparities is noted, we were interested mostly to describe potential socio-economic factors associated with and possibly responsible for the presence of such disparities. In this review we focused on five factors: education level, employment status, income, presence of substance addiction or abuse, and marital status. We describe the new method to quantify patients' socio-economic status and identify the group of high risk in terms of the transplant outcome, easily calculated social adaptability index, previously associated with clinical outcome in several patient populations including those with kidney transplant. At the end, based on literature analyzed we offer potential interventions that potentially can be used in order to reduce the degree of disparities. CONCLUSION: Based on review of literature socio-economic factors are associated with and possibly responsible for healthcare disparities. Social adaptability index allows quantifying the degree of socio-economic status and identifying the group of high risk for inferior transplant outcome.

Geographic disparities in arteriovenous fistula placement in patients approaching hemodialysis in the United States.

Arteriovenous fistula (AVF) is the preferred vascular access for hemodialysis (HD). Several factors associated with AVF placement have been identified (e.g., age, sex, race, comorbidities). We hypothesized that geographic location of patient residence might be associated with the probability of AVF placement as the initial access. We used the data from the United States Renal Data System (USRDS) database (2005-2008) linked to Medicare claims (2003-2008). Logistic regression was used to estimate specific characteristics of population associated with the AVF as first access placed or attempted for HD initiation. Our primary variable of interest was the geographic location, and the multivariate model was adjusted for age, sex, race, body mass index, primary cause of end-stage renal disease (ESRD), duration of pre-ESRD nephrology care, comorbidities, employment status, substance abuse, and income. Geographic location was determined using the data collected by the RUCA project and divided population into metropolitan, micropolitan, and rural categories. Patients (n = 111,953) identified from the USRDS database with linked Medicare claims were examined. Rates of fistula placement in the metropolitan, micropolitan, and rural population were 18.5%, 22.4%, and 21.6%, respectively. In comparison, patients who received catheter as the first access were 81.5%, 77.6% and 78.4%, respectively. The odds ratio of AVF placement as a first HD access in the rural and metropolitan population compared with the micropolitan population were 0.96 (0.90-1.03; P = 0.26) and 0.80 (0.76-0.84; P < 0.001), respectively. Our results indicate the presence of geographic disparities in AVF placement with decreased rates of AVF as the first access created in the metropolitan (but not rural) populations compared with the micropolitan communities.

Factors predicting failure of AV "fistula first" policy in the elderly.

An arteriovenous fistula (AVF) is the preferential hemodialysis (HD) access. The goal of this study was to identify factors associated with pre-dialysis AVF failure in an elderly HD population. We used United States Renal Data System + Medicare claims data to identify patients ≥ 67 years old who had an AVF as their initial vascular access placed pre-dialysis. Failure of the AVF to be used for initial HD, was used as the outcome. Logistic regression model was used to identify factors associated with AVF failure. The study cohort consisted of 20,360 subjects (76.2 ± 6.02 year old, 58.5% men). Forty-eight percent of patients initiated dialysis using an AVF, while 52% used a catheter or an AVG. The following variables found to be associated with AVF failure when an AVF was created at least 4 months pre-HD initiation: older age (odds ratio [OR] 1.01; 95% confidence interval [CI] 1.00-1.02), female gender (OR 1.69; 95% CI 1.55-1.83), black race (OR 1.41; 95% CI 1.26-1.58), history of diabetes (OR 1.22; 95% CI 1.06-1.39), cardiac failure (OR 1.26; 95% CI 1.15-1.37), and shorter duration of pre-end-stage renal disease (ESRD) nephrology care (OR for a nephrology care of less than 6 months prior to ESRD of 1.22 compared with a pre-ESRD nephrology follow up of more than 12 months; 95% CI 1.07-1.38). OR for AVF failure for the entire cohort showed similar findings. In an elderly HD population, there is an association of older age, female gender, black race, diabetes, cardiac failure and shorter pre-ESRD nephrology care with predialysis AVF failure.

Disparities in arteriovenous fistula placement in older hemodialysis patients.

The benefits of an arteriovenous fistula (AVF) as the preferred vascular access for hemodialysis have been clearly demonstrated. However, only about 20% of patients in the United States initiate hemodialysis with an AVF. In this study, we assessed whether disparities exist in the type of first hemodialysis access placed prior to dialysis start (rather than that used at dialysis initiation), to detect whether certain disadvantaged groups might have lower likelihood of AVF placement. Study cohort of 118,767 incident hemodialysis patients ≥67 years of age (1/2005-12/2008) derived from the United States Renal Data System was linked with Medicare claims data to identify the type of initial access placed predialysis. We used logistic regression model with outcome being the initial predialysis placement of an AVF as opposed to an arteriovenous graft or a central venous catheter. Increasing age, female sex, black race, lower body mass index, urban location, certain comorbidities, and shorter pre-end-stage renal disease nephrology care are all associated with a significantly lower likelihood of AVF placement as initial access predialysis. Our study suggests the presence of significant disparities in the placement of an AVF as initial hemodialysis vascular access. We suggest that additional attention should be paid to these patient groups to improve disparities by patient education, earlier referral, and close follow-up.

Short-term responses of the kidney to high altitude in mountain climbers.

In high-altitude climbers, the kidneys play a crucial role in acclimatization and in mountain sickness syndromes [acute mountain sickness (AMS), high-altitude cerebral edema, high-altitude pulmonary edema] through their roles in regulating body fluids, electrolyte and acid-base homeostasis. Here, we discuss renal responses to several high-altitude-related stresses, including changes in systemic volume status, renal plasma flow and clearance, and altered acid-base and electrolyte status. Volume regulation is considered central both to high-altitude adaptation and to maladaptive development of mountain sickness. The rapid and powerful diuretic response to the hypobaric hypoxic stimulus of altitude integrates decreased circulating concentrations of antidiuretic hormone, renin and aldosterone, increased levels of natriuretic hormones, plasma and urinary epinephrine, norepinephrine, endothelin and urinary adrenomedullin, with increased insensible fluid losses and reduced fluid intake. The ventilatory and hormonal responses to hypoxia may predict susceptibility to AMS, also likely influenced by multiple genetic factors. The timing of altitude increases and adaptation also modifies the body's physiologic responses to altitude. While hypovolemia develops as part of the diuretic response to altitude, coincident vascular leak and extravascular fluid accumulation lead to syndromes of high-altitude sickness. Pharmacological interventions, such as diuretics, calcium blockers, steroids, phosphodiesterase inhibitors and ß-agonists, may potentially be helpful in preventing or attenuating these syndromes.

Renal transplantation in the setting of early steroid withdrawal: a comparison of rabbit antithymocyte globulin induction dosing in two eras.

BACKGROUND: Modern immunosuppression and rabbit antithymocyte globulin (rATG) have facilitated the success of early steroid withdrawal (ESW) protocols. Little data exist on optimal rATG dosing in ESW protocols. METHODS: Rejection at 12 months in era 1 (four doses of rATG, 1.25 mg/kg) vs. era 2 (three doses of rATG, 1.25 mg/kg) was the primary endpoint. Secondary endpoints included patient and graft survival, renal function and infectious complications. Factors associated with rejection at 1 year were identified. RESULTS: 199 patients received rATG induction and ESW: 102 in era 1 and 97 in era 2. Compared to era 1, era 2 was not associated with worse outcomes, including rejection, renal function, infection or graft survival. Rejection at 1 year and uncensored graft survival differed between the dosing groups. Rejection rates were significantly higher in the <4 mg/kg group compared to the 4-5.9-mg/kg and the ≥6-mg/kg groups, whereas uncensored graft survival was the lowest in the ≥6-mg/kg group. Factors associated with rejection at 12 months included: rATG dose received of 4-5.9 versus <4 mg/kg (OR 0.20, 95% CI 0.036-0.85, p = 0.026); recipient age (per year, OR 0.94, 95% CI 0.89-1.0, p = 0.038); panel reactive antibody 10-79.9 versus <10% (OR 5.4, 95% CI 1.2-25, p = 0.030) and rATG dose held (OR 4.0, 95% CI 1.0-15, p = 0.049). CONCLUSIONS: A comparison of rATG dosing based on era did not result in a significant difference in rejection, renal function, infection or graft survival. However, when evaluating the study population based on actual dose received there were notable differences in both rejection rates and uncensored graft survival.

Fistula first is not always the best strategy for the elderly.

Whether placing a fistula first is the superior predialysis approach among octogenarians is unknown. We analyzed data from a cohort of 115,425 incident hemodialysis patients ≥67 years old derived from the US Renal Data System with linked Medicare claims, which allowed us to identify the first predialysis vascular access placed rather than the first access used. We used proportional hazard models to evaluate all-cause mortality outcomes based on first vascular access placed, considering the fistula group as the reference. In the study population, 21,436 patients had fistulas as the first predialysis access placed, 3472 had grafts, and 90,517 had catheters. Those patients with a catheter as the first predialysis access placed had significantly inferior survival compared with those patients with a fistula (HR=1.77; 95% CI=1.73 to 1.81; P<0.001). However, we did not detect a significant mortality difference between those patients with a graft as the first access placed and those patients with a fistula (HR=1.05; 95% CI=1.00 to 1.11; P=0.06). Analyzing mortality stratified by age groups, grafts as the first predialysis access placed had inferior mortality outcomes compared with fistulas for the 67 to ≤79-years age group (HR=1.10; 95% CI=1.02 to 1.17; P=0.007), but differences between these groups were not statistically significant for the 80 to ≤89- and the >90-years age groups. In conclusion, fistula first does not seem to be clearly superior to graft placement first in the elderly, because each strategy associates with similar mortality outcomes in octogenarians and nonagenarians.

Recipient's unemployment restricts access to renal transplantation.

Equitable distribution of a scarce resource such as kidneys for transplantation can be a challenging task for transplant centers. In this study, we evaluated the association between recipient's employment status and access to renal transplantation in patients with end-stage renal disease (ESRD). We used data from the United States Renal Data System (USRDS). The primary variable of interest was employment status at ESRD onset. Two outcomes were analyzed in Cox model: (i) being placed on the waiting list for renal transplantation or being transplanted (whichever occurred first); and (ii) first transplant in patients who were placed on the waiting list. We analyzed 429 409 patients (age of ESRD onset 64.2 ± 15.2 yr, 55.0% males, 65.1% White). Compared with patients who were unemployed, patients working full time were more likely to be placed on the waiting list/transplanted (HR 2.24, p < 0.001) and to receive a transplant once on the waiting list (HR 1.65, p < 0.001). Results indicate that recipient's employment status is strongly associated with access to renal transplantation, with unemployed and partially employed patients at a disadvantage. Adding insurance status to the model reduces the effect size, but the association still remains significant, indicating additional contribution from other factors.

The role of initial hemodialysis vascular access in the outcome of subsequent kidney transplantation.

The role of initial hemodialysis vascular access in the subsequent kidney transplant outcome is unclear. Study population was derived from the United States Renal Data System and included adult patients with end-stage renal disease who started HD 1/1/2005-9/1/2009 and subsequently received at least one kidney transplant. Primary outcome variables were death-censored graft loss and all-cause recipient mortality. Among the study population (n = 17 157), 12 428 (72.4%) patients were initiated on HD with a catheter, 4090 (23.8%) patients with an arterio-venous fistula (AVF), and 639 (13.7%) patients with an arterio-venous graft (AVG). The rate of death-censored kidney allograft loss in AVF and AVG groups was not significantly different from the catheter group (HR, 0.82; p = 0.07 and HR, 0.68; p = 0.13, respectively). All-cause mortality of patients initiated on HD with AVG (HR, 0.761; p = 0.21) was not significantly different compared to those with catheters. However, all-cause mortality in the AVF group was lower compared to patients initiated on HD with catheters (HR, 0.65; p = 0.001). AVF used at the initiation of HD was associated with lower rate of all-cause mortality after kidney transplantation compared to the catheter. The type of initial vascular access for hemodialysis was not associated with kidney allograft survival.

Access to renal transplantation in the diabetic population-effect of comorbidities and body mass index.

BACKGROUND: In this study, we hypothesized that higher level of comorbidity and greater body mass index (BMI) may mediate the association between diabetes and access to transplantation. METHODS: We used data from the United States Renal Data System (01/01/2000-24/09/2007; n = 619,151). We analyzed two outcomes using Cox model: (i) time to being placed on the waiting list or transplantation without being listed and (ii) time to transplantation after being listed. Two primary Cox models were developed based on different levels of adjustment. RESULTS: In Cox models adjusted for a priori defined potential confounders, history of diabetes was associated with reduced transplant access (compared with non-diabetic population) - both for wait-listing/transplant without being listed (hazard ratio, HR = 0.80, p < 0.001) and for transplant after being listed (HR = 0.72, p < 0.001). In Cox models adjusted for BMI and comorbidity index along with the potential confounders, history of diabetes was associated with shorter time to wait-listing or transplantation without being listed (HR = 1.07, p < 0.001), and there was no significant difference in time to transplantation after being listed (HR = 1.01, p = 0.42). CONCLUSION: We demonstrated that higher level of comorbidity and greater BMI mediate the association between diabetes and reduced access to transplantation.