Epidemiology of hemodialysis vascular access in the United States.

Reemergence of the importance of vascular access in the care of the chronic hemodialysis patient has gained prominence due to renewed interest in clinical outcomes and evidence-based interventions. Further fueled by anticipated regulatory changes in the reimbursement for dialysis care in the United States by 2011 and beyond, the drive to improve quality of care for hemodialysis patients has identified vascular access issues as a key contributor to outcomes. Focus has shifted from simply providing any hemodialysis vascular access to a strong preference for the use of native arteriovenous fistulas and subsequently to a need for reducing exposure to central venous catheters. Combined, these goals have forced a reevaluation of the role of arteriovenous grafts. The context and events associated with the evolution of thinking on these issues as well as available data supporting them are discussed. The key leadership role of nephrologists is emphasized along with a summary of problems and proposed solutions.

Extremes of glycemic control (HbA1c) increase hospitalization risk in diabetic hemodialysis patients in the USA.

BACKGROUND/AIMS: Because the relation between glycemic control and clinical outcomes found in the general diabetic population has not been established in diabetic hemodialysis patients, we evaluated the association between glycemic control and hospitalization risk. METHODS: We performed a primary retrospective data analysis on 23,829 hemodialysis patients with diabetes mellitus. Hemoglobin A(1c) at baseline and hospitalization events over the subsequent 12 months were analyzed and logistic regression models constructed for unadjusted, case mix-adjusted and case mix plus lab- adjusted data. Models were also constructed for cardiovascular, vascular access and sepsis hospitalizations. RESULTS: Eighty percent had type 2 DM, 5% type 1 and 14% not specified. The groups had similar mean HbA(1c) levels, 6.8 +/- 1.6%. Among all patients, the mean HbA(1c) values were >7% in 35%. The odds ratio of hospitalizations grouped by baseline HbA(1c) was significant at extremes of <5% and >11%. Similar relationships were evident for the subset of type 2 DM and in the analysis for hospitalizations due to sepsis. CONCLUSION: Extremely high and low HbA(1c) values are associated with hospitalization risk in diabetic hemodialysis patients. Prospective studies are needed to determine whether meeting recommended HbA(1c) targets might improve outcomes without posing additional risks in this population.

Daily and nocturnal hemodialysis: how do they stack up?

A growing number of articles in the literature describe experiences using more frequent hemodialysis (HD), either short daily or long nocturnal. Most of these publications highlight successes obtained by these programs with a fragmented look at specific areas and outcomes. This review of published results from the use of these therapies shows that universal improvement is noted in dialysis adequacy, nutrition, quality of life, blood pressure control, fluid and electrolyte balance, and hospitalizations when these parameters are mentioned. However, data reporting is often incomplete. Most studies do not have adequate control groups, patient populations are often different from the standard HD population, and many have small numbers that preclude statistical significance. Nonuniformity of patient selection and study design prevents accurate comparison and pooling of patient data. In some cases, the same patients' data for the same periods of observation are reported in several studies. Despite data that can be characterized as preliminary and anecdotal, the results reported in this review show remarkable patient improvement worthy of serious consideration by the renal community. To reach a level of evidence that will be widely acceptable, the renal community needs to partner with such government institutions as the National Institutes of Health and the Health Care Financing Administration to study systematically the outcomes and costs associated with using more frequent HD. In the process, important ramifications of such a cooperative study, including potential changes in policy, need to be considered.

Limitations of the facility-specific standardized mortality ratio for profiling health care quality in dialysis.

Health care quality is assessed by profiling measures of care and/or health outcomes. However, such tools to measure outcome as standardized mortality ratio (SMR) are often used without thorough validation of their strengths and limitations. Our study compared the dialysis facility-specific SMR and SMR-based rating using different statistical methods and followed them over time. All Fresenius Medical Care, North America dialysis facilities (n = 377) that contributed patient data from 1993 to 1995 (>103,500 patient-years) were included. Four distinct statistical methods (US Renal Data System [USRDS], Poisson, logistic, and Cox regression) were used to compute facility-specific SMRs and rank and classify facilities. The analysis compared the SMR and SMR-based rating of dialysis facilities between SMR method and over time. Different methods produced statistically significant differences in SMR distribution (P < 0.05). The USRDS method produced SMR values that decreased over time (P < 0.001). Based on 90% confidence intervals to determine outliers, the SMR-dependent ranking of dialysis facilities varied by method (P < 0.001). SMR-based ranking was stable over time except for the USRDS method (P < 0.001). Contingency table analysis showed up to a 33% total misclassification rate between SMR methods when ranking facilities. The facility-specific SMR and SMR-based ranking are both sensitive to statistical technique. Because the SMR yields different results in a year and over time and because there is no demonstrable gold standard, conclusions based on any one technique are unstable and unreliable. Regulatory monitoring, actions, and/or performance awards should be avoided based on this measure. However, a facility-specific SMR estimated in any valid way may be useful as an epidemiological research tool.

The treatment of anemia in peritoneal dialysis patients.

The management of anemia in patients with end-stage renal disease (ESRD) treated with peritoneal dialysis (PD) has gained increasing attention over the past decade, similar to patients on hemodialysis (HD). However, there are many differences between the 2 renal replacement therapies that pose unique challenges and solutions for monitoring, diagnosis and treatment of anemia in PD patients. These differences are not always evident and may be the result of different patient selection, physical, emotional and motivational factors, specific requirements of the modality or an indeterminate blend of infinite gradations of all these factors. This review will highlight current issues in anemia management in PD patients.

Hemodialyzed type I and type II diabetic patients in the US: Characteristics, glycemic control, and survival.

Diabetes mellitus (DM) constitutes a major end-stage renal disease (ESRD) health problem. Glycemic control is fundamental to the management of diabetes and its complications, and relies on monitoring of hyperglycemia. We therefore performed a primary data analysis of glycemic control and survival on a large national ESRD database. Ninety-five percent of patients with DM had type II diabetes (N = 23,504), and five percent had type I diabetes (N = 1,371). For the combined population, the mean hemoglobin A1c (HgbA1c) was 6.77%, and the mean random blood glucose was 168 mg/dl. Mean HgbA1c values were >7.0% in 35% and >8.5% in 14%. Mean HgbA1c values were below 5% in 11.3% of patients. Type I study patients tended to have higher HgbA1c values. Most patients (75.8%) had three or more random blood glucose determinations within 90 days preceding the HgbA1c measurement. The HgbA1c showed only a weak correlation with mean random glucose values (R2 0.3716; s.e. = 1.36). The survival rates in the subsequent 12-month period ranged from 80 to 85% across different HgbA1c strata. Kaplan-Meier survival curves grouped by HgbA1c levels showed no correlation between HgbA1c and survival at 12 months. More studies are needed to refine recommendations for the role of HgbA1c and glycemic control in this patient population.

Daily hemodialysis: a dialysis provider perspective.

Regardless of size, ownership or corporate structure, the goal of the dialysis provider is to deliver the best renal substitution therapy in the safest and most convenient manner, at a cost commensurate with reimbursement. This paper reviews the available data on daily hemodialysis, focusing on its ability to satisfy this goal. In addition, it examines the potential influence of frequency, time, and dose of dialysis on clinical outcomes of various series over the last 3 decades. The available data strongly suggest the clinical benefits of daily hemodialysis, but are not sufficient to show statistically better outcomes. Under the present reimbursement system, daily hemodialysis is not economically feasible in the United States. Prospective clinical trials designed to prove the benefits of these therapies and justify their reimbursement are needed.

Association between prevalent care process measures and facility-specific mortality rates.

BACKGROUND: Medical communities often develop practice guidelines recommending certain care processes intended to promote better clinical outcome among patients. Conformance with those guidelines by facilities is then monitored to evaluate care quality, presuming that the process is associated with and can be used reliably to predict clinical outcome. Outcome is often monitored as a facility-specific mortality rate (SMR) standardized to the mix of patients treated, also presuming that inferior outcome implies a suboptimal process. The U.S. Health Care Financing Administration monitors three practice guidelines, called Core Indicators, in dialysis facilities to assist management of its end-stage renal disease program: (1) patients' hematocrit values should exceed 30 vol%, (2) the urea reduction ratio (URR) during dialysis should equal or exceed 65%, and (3) patients' serum albumin concentrations should equal or exceed 3.5 g/dL. METHODS: The associations of a facility-specific SMR were evaluated with the fractions of hemodialysis patients not conforming to (that is, at variance with) the Core Indicators during three successive years (1993 to 1995) in large numbers of facilities (394, 450, and 498) using one-variable and multivariable statistical models. Three related strategies were used. First, the association of the SMR with the fraction of patients not meeting the guideline was evaluated. Second, each facility was classified by whether its SMR exceeded the 80% confidence interval above 1.0 (worse than 1.0, Group 3), was less than the interval below 1.0 (better than 1.0, Group 1), or was within the interval (Group 2). The fraction of those patients who did not meet the Indicator guidelines was then evaluated in each group. Third, the ability of variance from Indicator guidelines to predict into which of the three SMR groups a facility would be categorized was evaluated. RESULTS: SMR was directly correlated with variance from the Indicator guidelines, but the strengths of the associations were weak particularly for the hematocrit (R(2) = 2.2%, 5.6, and 2.2 for each of the 3 years) and URR Indicators (R(2) = 2.6, 0.6, 3.3). It was stronger for the albumin Indicator (R(2) = 11.6, 20.4, 21.8). The fractions of patients falling outside of the Indicator guidelines tended to be higher in the highest SMR group. The groups were not well separated, however, particularly for the hematocrit and URR Indicators, and there was substantial overlap between them. Finally, although the likelihood that a facility would be a member of the high or low SMR group was associated with fractional variance from Core Indicator guidelines, the strengths of association were weak, and the probability that a facility would be a member of the high or low group could not be easily distinguished from the probability that it would be a member of the middle group. CONCLUSIONS: While there were statistical associations between SMR and the fraction of patients in facilities who were at variance with these guidelines, they were weak and variances from the guidelines could not be used reliably to predict high or low SMR. Such findings do not imply that measures reflecting anemia, dialysis dose, or medical processes that influence serum albumin concentration are irrelevant to the quality of care. They do suggest, however, that more attention needs be paid to these and other associates and causes of mortality among dialysis patients when developing care process indicator guidelines.

Factors associated with inadequate blood pressure control in hypertensive hemodialysis patients.

Hypertension is common in hemodialysis patients and increases cardiovascular morbidity and mortality. We determined the prevalence of inadequate control of hypertension in 489 patients receiving hemodialysis and identified factors associated with uncontrolled hypertension. We interviewed the patients and abstracted demographic and clinical information from a computerized database. The prevalence of uncontrolled hypertension (average predialysis blood pressure, > or =160/90 mm Hg) was 62%. Ninety-one percent of patients with uncontrolled hypertension were receiving submaximal antihypertensive drug therapy, and 59% withheld their medications before dialysis. Uncontrolled hypertensives had a greater interdialytic weight gain (3.8% v 3.5%, P = 0.07) and a greater excess weight gain (3.1 +/- 1.6 kg v 2.5 +/- 1.4 kg; P < 0.05) compared with controlled hypertensives. Patients with uncontrolled hypertension showed higher interdialytic weight gain (2.7 +/- 0.06 kg v 2.2 +/- 0.13 kg; P < 0.05), were more likely to be black (94% v 81%; P < 0.05), were more likely to have hypertension as the cause of their end-stage renal disease (ESRD) (42% v 24%; P < 0.05), and had been receiving hemodialysis for a shorter time (4.3 +/- 2 yr v 6.1 +/- 0.9 yr; P < 0.05) compared with normotensive patients. There was significant correlation between diastolic blood pressure and both interdialytic weight gain (r = 0.31, P < 0.05) and percent weight gain (r = 0.34, P < 0.05) in the hypertensive but not in the normotensive patients (r = -0.21). Interdialytic weight gain and hypertension as a cause of ESRD were independent predictors of predialysis systolic blood pressure. We conclude that hypertension is uncontrolled in most patients undergoing hemodialysis. Submaximal antihypertensive therapy, excessive interdialytic weight gain, and withholding antihypertensive medication before dialysis are correctable factors potentially contributing to uncontrolled hypertension.