Growth rates in pediatric dialysis patients and renal transplant recipients

We compared growth rates by modality over a 6- to 14-month period in 1,302 US pediatric end-stage renal disese (ESRD) patients treated during 1990. Modality comparisons were adjusted for age, sex, race, ethnicity, and ESRD duration using linear regression models by age group (0.5 to 4 years, 5 to 9 years, 10 to 14 years, and 15 to 18 years). Growth rates were higher in young children receiving a transplant compared with those receiving dialysis (ages 0.5 to 4 years, delta = 3.1 cm/yr v continuous cycling peritoneal dialysis [CCPD], P < 0.01; ages 5 to 9 years, delta = 2.0 to 2.6 cm/yr v CCPD, chronic ambulatory peritoneal dialysis (CAPD), and hemodialysis, P < 0.01). In contrast, growth rates in older children were not statistically different when comparing transplantation with each dialysis modality. For most age groups of transplant recipients, we observed faster growth with alternate-day versus daily steroids that was not fully explained by differences in allograft function. Younger patients (<15 years) grew at comparable rates with each dialysis modality, while older CAPD patients grew faster compared with hemodialysis or CCPD patients (P < 0.02). There was no substantial pubertal growth spurt in transplant or dialysis patients. This national US study of pediatric growth rates with dialysis and transplantation shows differences in growth by modality that vary by age group.

Vascular access survival among incident hemodialysis patients in the United States

Vascular access failure causes substantial morbidity to hemodialysis patients. We sought to identify factors determining survival of the permanent vascular access in use at the start of end-stage renal disease during 1990 in a national sample of 784 incident hemodialysis patients insured by Medicare. Medicare claims records were used to identify access failures or revisions among patients with an arteriovenous (AV) fistula (n = 245) and an AV vascular graft (n = 539). A proportional hazards analysis of time to first failure or revision, controlled by stratification for sex, race, and cause of end-stage renal disease, was used to determine the effect of age, access type, and peripheral vascular disease on vascular access survival. Patients with an AV fistula and who were older than 65 years had a risk of access failure that was 24% lower than similar patients with an AV graft (P < 0.02). The relative risk of access failure for an AV fistula, but not an AV graft, varied significantly with age for patients younger than 65 years (P < 0.01). The relative risk of access failure for a patient with an AV fistula, compared with a patient of the same age with an AV graft, was 67% lower at the age of 40 years, 54% lower at the age of 50 years, and 24% lower at the age of 65 years. A history of peripheral vascular disease was associated with a 24% higher risk of AV graft or fistula failure (P = 0.05). Measures to decrease vascular access-related morbidity among hemodialysis patients should include reversing the current trend toward increasing use of AV grafts, particularly in patients younger than 65 years.

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.

Predictors of type of vascular access in hemodialysis patients

OBJECTIVE

Complications from vascular access account for 15% of hospital admissions among US hemodialysis patients. Complications are less frequent with arteriovenous fistulas than with synthetic grafts. We assessed clinical and nonclinical predictors of whether patients with end-stage renal disease (ESRD) starting hemodialysis receive a fistula or graft. We also investigated changes in practice between 1986-1987 and 1990.

DESIGN

Cross-sectional study.

SETTING

United States hemodialysis population.

PATIENTS

Random, national samples of ESRD patients who started hemodialysis in 1986-1987 (n=2741) or 1990 (n=1409) from United States Renal Data System Special Studies.

MAIN OUTCOME MEASURE

Type of permanent vascular access (arteriovenous fistula vs synthetic graft), analyzed using multivariate logistic regression.

RESULTS

Clinical and demographic factors as well as socioeconomic status, region of residence, and year starting hemodialysis predicted the type of vascular access. Overall, 56% of patients had grafts 30 days after starting dialysis, but graft use increased from 51% in 1986-1987 to 65% in 1990 (adjusted odds ratio [AOR], 1.67 for 1990 vs 1986-1987; 95% confidence interval [CI], 1.43-1.95; P<.001). Graft use (relative to fistula) varied by region of residence (ranging from AOR, 0.20; 95% CI, 0.14-0.28; P<.001 [New England], to AOR, 2.69; 95% CI, 2.03-3.58; P<.001 [East South Central]; both relative to the national average).

CONCLUSIONS

This national study documents large variations in the relative use of fistulas and grafts and a trend away from fistulas. The prevalence of comorbid conditions fails to explain these findings. Presentation and referral of patients early in the process of their ESRD, teaching surgeons to place fistulas, and training dialysis nurses to access fistulas may increase their use.

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.

Hemodialysis therapy in the United States: what is the dose and does it matter?

There is an ongoing discussion in the renal community about how to monitor the treatment of hemodialysis patients in the United States. Comparison of the US patient experience to that of other countries with populations of similar health status is one way to assess treatment. Another technique involves examining the level of dialysis therapy US patients receive. This paper reviews recent studies which found that the United States has higher mortality than both Japan and Europe and provides additional information as to why those comparisons might be underestimating the mortality differences. We also examine the data on the level of dialysis US patients receive, both as a prescription and as delivered care. We conclude that US patients receive less hemodialysis therapy than their European and Japanese counterparts, and that in general US patients are not receiving the level of dialysis they were prescribed. These factors are correlated with an increased mortality among US hemodialysis patients.

Analysis of the association of dialyzer reuse practices and patient outcomes

This historic prospective study assessed the relationship between dialyzer reuse practices and hemodialysis patient mortality through 1 year of follow-up. Medicare patient demographic and survival data were combined with dialyzer reuse data from the Centers for Disease Control and Prevention's annual survey of dialysis-related diseases. Data were analyzed for the US Medicare hemodialysis population of never transplanted patients prevalent on January 1, 1989, and January 1, 1990, who were treated in freestanding dialysis units that used primarily conventional (not high-flux) dialyzers. Time to mortality, or transplant, and other censoring on December 31st of each year was regressed with proportional hazards models on patient, dialysis unit, and reuse measures. Age-, race-, and diagnosis-standardized mortality ratios for dialysis units were also regressed with weighted least squares techniques against dialysis unit and reuse measures. The results showed that patients treated in dialysis units that disinfected dialyzers with a peracetic acid, hydrogen peroxide, acetic acid mixture, or glutaraldehyde experienced higher mortality than patients treated in units that used formalin or in units that did not reuse dialyzers. The relative risk of mortality, compared with patients treated in nonreuse dialysis units, was 1.17 (P = 0.010) for glutaraldehyde and 1.13 (P < 0.001) for the peracetic acid mixture. The relative risk for formalin compared with the reference group of nonreuse was 1.06 (P = 0.088). With adjustment for several patient and dialysis unit characteristics, dialyzer reuse with certain germicides was associated with a significantly elevated mortality risk. This elevated risk, the etiology of which is currently not known, may represent a large number of potentially avoidable deaths per year. Only a large, nationally based analysis of this type has sufficient sample size to detect mortality risks such as these.

Continuous ambulatory peritoneal dialysis and hemodialysis: comparison of patient mortality with adjustment for comorbid conditions

A historical prospective national sample of 1,725 diabetic and 2,411 non-diabetic Medicare end-stage renal disease (ESRD) patients incident from 1986 to 1987 was analyzed for the mortality of patients selected to receive continuous ambulatory peritoneal dialysis (CAPD) or hemodialysis (HD) with adjustment for patient characteristics, including the presence of comorbid conditions at onset of ESRD. Cox proportional hazards analyses were used to compare the mortality of CAPD and HD patients. Patients were followed from 30 days following onset of ESRD until two to four years post-onset. No statistically significant difference in relative mortality risk (RR) was found among non-diabetic patients selected for CAPD compared to HD (RR = 0.84 for CAPD versus HD, P = 0.25), while evidence of higher adjusted mortality for CAPD compared to HD was found among diabetic patients (RR = 1.26, P = 0.03). Mortality analyses adjusted for pre-treatment risk factors suggest that CAPD and HD provide incident non-diabetic ESRD patients with similar expected survival outcomes. Evidence that increased mortality was associated with CAPD among diabetic patients, particularly among elderly patients, suggests the need for further controlled studies of mortality among CAPD patients with diabetes.

Risk of peritonitis and technique failure by CAPD connection technique: a national study

Peritonitis has been a leading complication of long-term therapy with continuous ambulatory peritoneal dialysis (CAPD). This study was designed to evaluate the risk of peritonitis and technique failure according to the initial CAPD connection technique. Patients from all U.S. facilities starting CAPD therapy at home between January 1 and June 30, 1989 were followed for up to 21 months on the initial CAPD connection technique to change in technique or dialytic modality, to transplantation, death or loss to follow-up. Patients were grouped into standard connection techniques (SCT) (N = 1,133), Y-set (N = 1,067), standard UV set (N = 916) and O-set (N = 167). The time to first peritonitis episode was analyzed actuarially and by using the Cox proportional hazards model which adjusted for age, sex, race, cause of ESRD, CAPD program size and ESRD therapy prior to CAPD. Peritonitis occurred on average at 9.0 month intervals with SCT, 15.0 months with Y-set, 13.4 with standard UV and 9.4 with O-set. The relative risk (RR by Cox analysis) of first peritonitis compared to SCT was 0.60 (40% lower) for the Y-set (P less than 0.01), 0.75 for standard UV (P less than 0.01), and similar to SCT (RR = 0.96) for the O-set (NS), all else being equal. Analysis time to second (N = 1,271) peritonitis episode gave similar results as did analysis of time to CAPD technique failure. Significantly higher RR of peritonitis and technique failure was observed for younger and black patients. These findings suggest the utilization of connection techniques with superior results.