Ranil DeSilva

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.

Association between initial type of hemodialysis access used in the elderly and mortality

We hypothesized that certain subpopulations (elderly and those with greater comorbidity) may not have significant benefit from “fistula first” initiative. A cohort of incident hemodialysis patients from 2005 to 2007, who were ≥70 years old, was derived from the United States Renal Data System. Primary variable of interest was type of vascular access used at first outpatient hemodialysis (i.e., fistula, graft, or central catheter), with primary outcome of all‐cause mortality (time to death measured from the first outpatient hemodialysis). A cohort of 82,202 patients was stratified by age (70 to ≤80, 81 to ≤90, and >90). Each group demonstrated a survival benefit with the use of an arterio‐venous fistula compared with catheter (hazard ratio [HR] 0.56 [P < 0.001], HR 0.55 [P < 0.001], and HR 0.69 [P = 0.007], respectively). Comparing graft to with a catheter, both groups, 70 to ≤80 and 81 to ≤90, had significant benefit compared with catheter (HR 0.73, P < 0.001 and HR 0.74, P < 0.001, respectively). However, significance was lost in those ≥90 (HR 0.83, P = 0.354). When substratified by comorbidity, those 81 to ≤90 years old with a history of malignancy or peripheral vascular disease also did not reach significant benefit compared with a catheter (HR 0.88, P = 0.423 and HR 0.85, P = 0.221, respectively). While specific subgroups in the hemodialysis population exist where use of fistulas and grafts at time of dialysis initiation is not of proven statistical benefit to survival, elderly hemodialysis patients with comorbidities still appear to benefit from the use of fistulas and grafts.

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.

Social adaptability index predicts kidney transplant outcome: a single-center retrospective analysis

BACKGROUND Social adaptability index (SAI) is the composite index of socioeconomic status based upon employment status, education level, marital status, substance abuse and income. It has been used in the past to define populations at higher risk for inferior clinical outcomes. The objective of this retrospective study was to evaluate the association of the SAI with renal transplant outcome. METHODS We used data from the clinical database at the Beth Israel Deaconess Medical Center Transplant Institute, supplemented with data from United Network for Organ Sharing for the years 2001-09. The association between SAI and graft loss and recipient mortality in renal transplant recipients was studied using Cox model in the entire study population as well as in the subgroups based on age, race, sex and diabetes status. RESULTS We analyzed 533 end-stage renal disease patients (mean age at transplant 50.8 ± 11.8 years, 52.2% diabetics, 58.9% males, 71.1% White). Higher SAI on a continuous scale was associated with decreased risk of graft loss [hazard ratio (HR) 0.89, P < 0.05, per 1 point increment in the SAI] and decreased risk of recipient mortality (HR 0.84, P < 0.01, per 1 point increment in the SAI). Higher SAI was also significantly associated with decreased risk for graft loss/recipient mortality in some study subgroups (age 41-65 years, males, non-diabetics). CONCLUSIONS SAI has an association with graft and recipient survival in renal transplant recipients. It can be helpful in identifying patients at higher risk for inferior transplant outcome as a target population for potential intervention.

Homozygous lecithin:cholesterol acyltransferase (LCAT) deficiency due to a new loss of function mutation and review of the literature

BACKGROUND A case of homozygous familial lecithin:cholesterol acyltransferase (LCAT) deficiency with a novel homozygous LCAT missense mutation (replacement of methionine by arginine at position 293 in the amino acid sequence of the LCAT protein) is reported. METHODS AND RESULTS The probable diagnosis was suggested by findings of marked high density lipoprotein (HDL) deficiency, corneal opacification, anemia, and renal insufficiency. The diagnosis was confirmed by two dimensional gel electrophoresis of HDL, the measurement of free and esterified cholesterol, and sequencing of the LCAT gene. CONCLUSIONS In our view the most important aspects of therapy to prevent the kidney disease that these patients develop is careful control of blood pressure and lifestyle measures to optimize non HDL lipoproteins. In the future replacement therapy by gene transfer or other methods may become available.

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.

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

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.

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.

Association of education level with dialysis outcome

The impact of education on health care outcome has been studied in the past, but its role in the dialysis population is unclear. In this report, we evaluated this association. We used the United States Renal Data System data of end‐stage renal disease patients aged ≥18 years. Education level at the time of end‐stage renal disease onset was the primary variable of interest. The outcome of the study was patient mortality. We used four categories of education level: 0 = less than 12 years of education; 1 = high school graduate; 2 = some college; 3 = college graduate. Subgroups based on age, race, sex, donor type, and diabetic status were also analyzed. After adjustments for covariates in the Cox model, using individuals with less than 12 years of education as a reference, patients with college education showed decreased mortality with hazard ratio of 0.81 (95% confidence interval 0.69–0.95), P = 0.010. In conclusion, we showed that higher education level is associated with improved survival of patients on dialysis.

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.