Lazarus Jm

Predicting Hemodialysis Access Failure with Color Flow Doppler Ultrasound

Color flow doppler ultrasound examination of the hemodialysis access was conducted in 2,792 hemodialysis patients to evaluate its value in predicting hemodialysis access failure. After baseline assessment of vascular access function with clinical and laboratory tests including color flow doppler evaluation these patients were followed for a minimal of 6 months or until graft failure occurred (defined as surgery or angioplasty intervention, or graft loss). The patient demographics and vascular accesses were typical of a standard hemodialysis patient population. On the day of the color flow doppler examination systolic and diastolic blood pressure, hematocrit, urea reduction ratio, dialysis blood flow, venous line pressure at a dialysis blood flow of 250 ml/min, and access recirculation rate were measured. At the conclusion of the study 23.5% of the patients had access failure. Case mix predictors for access failure were determined using the Cox Model. Case mix predictors of access failure were race, non-white was higher than white (p < 0.005), younger accesses had a higher risk than older accesses (p < 0.025), accesses with prior thrombosis had a higher risk of failure (p = 0.042), polytetrafluoroethylene (PTFE) grafts had a higher risk than native vein fistulae (p < 0.05), loop PTFE grafts had a higher risk than straight PTFE grafts (p < 0.025), and upper arm accesses had a higher risk than forearm accesses (p = 0.033). Most significant, however, was decreased access blood flow as measured by color flow doppler (p < 0.0001). The relative risk of graft failure increased 40% when the blood flow in the graft decreased to less than 500 ml/min and the relative risk doubled when the blood flow was less than 300 ml/min. This study has shown that color flow doppler evaluation, quantifying blood flow in a prosthetic graft, can identify those grafts at risk for failure. In contrast, color doppler volume flow in native AV fistulae could not predict fistula survival. This technique is noninvasive, painless, portable, and reproducible. We believe that preemptory repair of an anatomical abnormality in vascular access grafts with decreased blood flow may decrease patient inconvenience, associated morbidity, and associated costs.

A Comparison of SF-36 and SF-12 Composite Scores and Subsequent Hospitalization and Mortality Risks in Long-Term Dialysis Patients

BACKGROUND AND OBJECTIVES The Short Form 12 (SF-12) has not been validated for long-term dialysis patients. The study compared physical and mental component summary (PCS/MCS) scores from the SF-36 with those from the embedded SF-12 in a national cohort of dialysis patients. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS All 44,395 patients who had scorable SF-36 and SF-12 from January 1, 2006, to December 31, 2006, and were treated at Fresenius Medical Care, North America facilities were included. Death and first hospitalization were followed for up to 1 year from the date of survey. Correlation and agreement were obtained between PCS-36 and PCS-12 and MCS-36 and MCS-12; then Cox models were constructed to compare associated hazard ratios (HRs) between them. RESULTS Physical and mental dimensions both exhibited excellent intraclass correlation coefficients of 0.94. Each incremental point for both PCS-12 and PCS-36 was associated with a 2.4% lower adjusted HR of death and 0.4% decline in HR for first hospitalization (both P < 0.0001). Corresponding improvement in HR of death for each MCS point was 1.2% for MCS-12 and 1.3% for MCS-36, whereas both had similar 0.6% lower HR for hospitalization per point (all P < 0.0001). CONCLUSIONS The use of the SF-12 alone or as part of a larger survey is valid in dialysis patients. Composite scores from the SF-12 and SF-36 have similar prognostic association with death and hospitalization risk. Prospective longitudinal studies of SF-12 surveys that consider responsiveness to specific clinical, situational, and interventional changes are needed in this population.

Outcomes Associated with In-Center Nocturnal Hemodialysis from a Large Multicenter Program

BACKGROUND AND OBJECTIVES The objective of this study was to evaluate epidemiology and outcomes of a large in-center nocturnal hemodialysis (INHD) program. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS This case-control study compared patients who were on thrice-weekly INHD from 56 Fresenius Medical Care, North America facilities with conventional hemodialysis patients from 244 facilities within the surrounding geographic area. All INHD cases and conventional hemodialysis control subjects who were active as of January 1, 2007, were followed until December 31, 2007, for evaluation of mortality and hospitalization. RESULTS As of January 1, 2007, 655 patients had been on INHD for 51 +/- 73 d. Patients were younger, there were more male and black patients, and vintage was longer, but they had less diabetes compared with 15,334 control subjects. Unadjusted hazard ratio was 0.59 for mortality and 0.76 for hospitalization. After adjustment for case mix and access type, only hospitalization remained significant. Fewer INHD patients were hospitalized (48 versus 59%) with a normalized rate of 9.6 versus 13.5 hospital days per patient-year. INHD patients had greater interdialytic weight gains but lower BP. At baseline, hemoglobin values were similar, whereas albumin and phosphorus values favored INHD. Mean equilibrated Kt/V was higher in INHD patients related to longer treatment time, despite lower blood and dialysate flow rates. CONCLUSIONS Patients who were on INHD exhibited excellent quality indicators, with better survival and lower hospitalization rates. The relative contributions of patient selection versus effect of therapy on outcomes remain to be elucidated in prospective clinical trials.

The association between blood pressure and mortality in ESRD-not different from the general population?

Hypertension (HTN) is a traditional cardiovascular risk factor and is prevalent in end‐stage renal disease (ESRD). There are no adequately powered prospective studies that explore the natural history and outcomes of HTN and blood pressure management in ESRD. Observational studies have not uniformly showed a relationship between HTN and mortality risk in this population. Furthermore, many studies paradoxically show an increased risk of death associated with low and “normal” blood pressure (BP), sometimes referred to as “reverse epidemiology.” We review findings from observational studies specifically performed in ESRD and provide an alternative interpretation—that patients with kidney disease on dialysis therapy are indeed different from the general population. At minimum, these differences may be based on the prevalence of cardiovascular morbidity, specifically the excessive prevalence of congestive heart failure. However, there are other reasons for ESRD patients, especially those on hemodialysis, to exhibit differential effects with regard to blood pressure and outcomes. We explore the implications of available observational evidence and recommend studies that elucidate the differences between ESRD and the general population. Because of the higher mortality risk associated with low or “normal” BP, diagnostic and therapeutic options and strategies for ESRD patients whose BP falls within “goal” should be addressed in future iterations of clinical practice guidelines. These strategies may include assessment of cardiac function and careful attention to achieving optimal fluid balance.

Change in Vascular Access and Hospitalization Risk in Long-Term Hemodialysis Patients

BACKGROUND AND OBJECTIVES Conversion from central venous catheters to a graft or a fistula is associated with lower mortality risk in long-term hemodialysis (HD) patients; however, a similar association with hospitalization risk remains to be elucidated. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS We conducted a prospective observational study all maintenance in-center HD patients who were treated in Fresenius Medical Care, North America legacy facilities; were alive on January 1, 2007; and had baseline laboratory data from December 2006. Access conversion (particularly from a catheter to a fistula or a graft) during the 4-month period from January 1 through April 30, 2007, was linked using Cox models to hospitalization risk during the succeeding 1-year follow-up period (until April 30, 2008). RESULTS The cohort (N = 79,545) on January 1, 2007 had 43% fistulas, 29% catheters, and 27% grafts. By April 30, 2007, 70,852 patients were still on HD, and among 19,792 catheters initially, only 10.3% (2045 patients) converted to either a graft or a fistula. With catheters as reference, patients who converted to grafts/fistulas had similar adjusted hazard ratios (0.69) as patients on fistulas (0.71), while patients with fistulas/grafts who converted to catheters did worse (1.22), all P < 0.0001. CONCLUSIONS Catheters remain associated with the greatest hospitalization risk. Conversion from a catheter to either graft or fistula had significantly lower hospitalization risk relative to keeping the catheter. Prospective studies are needed to determine whether programs that reduce catheters will decrease hospitalization risk in HD patients.

Dialyzer best practice: single use or reuse?

Outcome studies have shown either no additional risk or a small additional risk for hospitalization and mortality associated with reprocessing dialyzers. Although the risks from reprocessing dialyzers have yet to be fully elucidated, reuse can be done safely if it is performed in full compliance with the standards of Association for the Advancement of Medical Instrumentation (AAMI). Like most industrial processes, however, complete control of the reuse process in a clinical environment and full compliance with regulations at all times is difficult. Potential errors and breakdowns in the reuse process are continuing concerns. The quality controls for reprocessing of dialyzers are not equal to the rigor of the manufacturing process under the purview of the U.S. Food and Drug Administration (FDA). Therefore, if one were to determine “best practice,” single use is preferable to reuse of dialyzers based on medical criteria and risk assessment. The long‐term and cumulative effects of exposure to reuse reagents are unknown and there is no compelling medical indication for reprocessing of dialyzers. The major impediment when deciding to convert from reuse to single use of dialyzers is economic. The experience in Fresenius Medical Care—North America (FMCNA) facilities demonstrates that converting from a practice of reuse to single use is achievable. However, the overall economic impact of conversion to single use is provider specific. The dominance of reuse has been negated of late by a major shift in practice toward single use. Physicians and patients should be well informed in making decisions regarding the practice of single use versus reuse of dialyzers.

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 A1c 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 HbA1c levels, 6.8 ± 1.6%. Among all patients, the mean HbA1c values were >7% in 35%. The odds ratio of hospitalizations grouped by baseline HbA1c 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 HbA1c values are associated with hospitalization risk in diabetic hemodialysis patients. Prospective studies are needed to determine whether meeting recommended HbA1c targets might improve outcomes without posing additional risks in this population.