Daily Dialysis Kt/V and Flexible Schedules: Is it Possible to Control Efficiency, When and How?

Background

Daily hemodialysis is a promising treatment schedule but uniform criteria for defining efficiency are lacking.

Methods

On our daily dialysis (DD) schedule, duration is flexible (2–3 hours, patients are free to add up to 30min/session), Qb 250–350 mL/min; dialyser 1.6–1.8 m2. Study was performed on 12 pts on DD for ≥2 months, with ≥4 Kt/V on subsequent days, tested in the same laboratory. Goal: To evaluate variability and identify a simple method for weekly calculation, Kt/V was assessed for 133 sessions.

Results

On flexible DD, variability of Kt/V-session is high (relative error 4.9%-22%). On flexible schedules, within the time range chosen (2–3 hours) variability of average hourly Kt/V is lower (standard deviation: min (0.014; max (0.052 hour, relative error 4.9%-10%) allowing calculation of weekly Kt/V (averaging 3 sessions: relative error <6%) suitable for clinical practice.

Conclusions

Flexible schedules, allowing patients to increase treatment time, are an interesting clinical option, but a challenge for Kt/V assessment.

Effect of frequent or extended hemodialysis on cardiovascular parameters: a meta-analysis

BACKGROUND

Increased left ventricular (LV) mass is a risk factor for cardiovascular mortality in patients with chronic kidney failure. More frequent or extended hemodialysis (HD) has been hypothesized to have a beneficial effect on LV mass.

STUDY DESIGN

Meta-analysis.

SETTING & POPULATION

MEDLINE literature search (inception to April 2011), Cochrane Central Register of Controlled Trials and ClinicalTrials.gov using the search terms "short daily HD," "daily HD," "quotidian HD," "frequent HD," "intensive HD," "nocturnal HD," and "home HD."

SELECTION CRITERIA FOR STUDIES

Single-arm cohort studies (with pre- and post-study evaluations) and trials examining the effect of frequent or extended HD on cardiac morphology and function and blood pressure parameters. Studies of hemofiltration, hemodiafiltration, and peritoneal dialysis were excluded.

INTERVENTION

Frequent (2-8 hours, >3 times weekly) or extended (>4 hours, 3 times weekly) HD compared with conventional (≤4 hours, 3 times weekly) HD.

OUTCOMES

Absolute changes in cardiac morphology and function, including LV mass index (LVMI; primary) and blood pressure parameters (secondary).

RESULTS

We identified 38 single-arm studies, 5 crossover trials, and 3 randomized controlled trials. By meta-analysis of 23 study arms, frequent or extended HD significantly reduced LVMI from baseline (-31.2 g/m(2), 95% CI, -39.8 to -22.5; P < 0.001). The 3 randomized trials found a less pronounced net reduction in LVMI (-7.0 g/m(2); 95% CI, -10.2 to -3.7; P < 0.001). LV ejection fraction improved by 6.7% (95% CI, 1.6% to 11.9%; P = 0.01). Other cardiac morphologic parameters showed similar improvements. There also were significant decreases in systolic, diastolic, and mean blood pressure and mean number of antihypertensive medications.

LIMITATIONS

Paucity of randomized controlled trials.

CONCLUSIONS

Conversion from conventional to frequent or extended HD is associated with improvements in cardiac morphology and function, including LVMI and LV ejection fraction, respectively, and several blood pressure parameters, which collectively might confer long-term cardiovascular benefit. Trials with long-term clinical outcomes are needed.

An economic assessment model for in-center, conventional home, and more frequent home hemodialysis

More intensive and/or frequent hemodialysis may provide clinical benefits to patients with end-stage renal disease; however, these dialysis treatments are more convenient to the patients if provided in their homes. Here we created a standardized model, based on a systematic review of available costing literature, to determine the economic viability of providing hemodialysis in the home that arrays costs and common approaches for assessing direct medical and nonmedical costs. Our model was based on data from Australia, Canada, and the United Kingdom. The first year start-up costs for all hemodialysis modalities were higher than in subsequent years with modeled costs for conventional home hemodialysis lower than in-center hemodialysis in subsequent years. Modeled costs for frequent home hemodialysis was higher than both in-center and conventional home hemodialysis in the United Kingdom, but lower than in-center hemodialysis and higher than conventional home hemodialysis in Australia and Canada in subsequent years. The higher costs of frequent compared to conventional home hemodialysis were because of higher consumable usage due to dialysis frequency. Thus, our findings reinforce the conclusions of previous studies showing that home-based conventional and more frequent hemodialysis may provide clinical benefit at reasonable costs.

The efficacy of short daily dialysis--a single-centre experience

Studies have shown that patients converted to short daily haemodialysis (SDHD) have reported many clinical benefits, decreased complications during dialysis and a better quality of life.A six-month prospective cohort study was conducted to examine the efficacy of SDHD to patients previously receiving three times per week haemodialysis therapy. Following informed consent, participants received haemodialysis daily, Monday-Saturday, between 2 and 2.5 hours for each treatment and followed-up for a six-month period. The participants continued to experience hypotension, cramping and headache and were noncompliant with fluid intake. There was a gradual reduction in blood pressure, cessation of antihypertensives and reduction of erythropoietin therapy (ERT). There were no hospital admissions or reports of access complications. The nursing staff reported an increase in activity levels and nursing interventions with the participants following conversion to SDHD. However, the participants reported a better quality of life.

Daily dialysis: exploring the impact for patients and nurses

Daily haemodialysis is different to conventional haemodialysis in that the person receives at least five haemodialysis sessions per week. Increased haemodialysis sessions demonstrate an increased quality of life, decreased intradialytic complications and a decrease in comorbidities that are experienced by people receiving conventional haemodialysis. These improvements in health status are offset with substantial consequences on time management for patient and staff as well as the increased financial cost of supplies. This paper compares conventional haemodialysis with daily haemodialysis and examines the benefits and limitations of daily haemodialysis. We suggest that people who receive daily haemodialysis are able to achieve their fullest health potential with an increased quality of life, less comorbidity and less hospitalization.

Switching from Three Times a Week to Short Daily Online Hemodiafiltration: Effects on Acid-Base Balance

Aims

This study examines the effect of a change from the standard 4–5 hours 3 times a week of online hemodiafiltration (OL-HDF) to 2–2.5 hours daily (6 times a week) OL-HDF, on acid-base balance, and attempts assess the modifications of acid-base parameters, ionic concentration, and electrical charges of albumin and phosphate available for diffusion and convection mechanisms across the membrane and subsequent infusion.

Methods

In 18 patients on online HDF, blood gas, electrolytes (Na, K, Cl), lactate, phosphate, albumin, apparent strong ion difference (SIDa), effective strong ion difference (SIDe), strong ion gap (SIG), anion gap (AG), and bicarbonate and pH time-averaged concentration (TAC) and time-averaged deviation (TAD) variables were evaluated at baseline, and 1, 3, 6, 9, and 12 months after patients were switched to daily OL-HDF. Additionally, in 12 patients, the same parameters measured simultaneously at dialyzer inlet, outlet, and after reinfusion were studied.

Results

Throughout the study, weekly single-pool Kt/V, equilibrated Kt/V, and TAC urea remained constant. However, standard Kt/V increased and TAD urea decreased on daily OL-HDF. There were no statistical differences during the time span of 12 months in pH, cations (Na, K), anions (Cl, HCO–3 AG, and lactate), or SIDa, SIDe, and SIG pre-HDF; while pH and HCO3– TAD decreased from 0.02 and 1.02 ± 0.74 mEq/L, to 0.01 and 0.64 ± 0.52 mEq/L, respectively (p<0.01). Net albumin charge and AG increased significantly at dialyzer outlet and decreased after reinfusion.

Conclusions

We did not observe changes in the acid-base balance in patients who switched from 3 times a week to short daily OL-HDF. The main benefit observed was a lower pH and bicarbonate TAD. This shows a better physiology for daily OL-HDF.

Phosphorus balance with daily dialysis

Hyperphosphatemia is an almost universal finding in patients with end-stage renal disease and is associated with increased all-cause mortality, cardiovascular mortality, and vascular calcification. These associations have raised the question of whether reducing phosphorus levels could result in improved survival. In light of the recent findings that increased per-session dialysis dose, as assessed by urea kinetics, did not result in improved survival, the definition of adequacy of dialysis should be re-evaluated and consideration given to alternative markers. Two alternatives to conventional thrice weekly dialysis (CHD) are nocturnal hemodialysis (NHD) and short daily hemodialysis (SDHD). The elimination kinetics of phosphorus as they relate to these alternative daily dialysis schedules and the clinical implications of overall phosphorus balance are discussed here. The total weekly phosphorus removal with NHD is more than twice that removed by CHD (4985 mg/week +/- 1827 mg vs. 2347 mg/week +/- 697 mg) and this is associated with a significantly lower average serum phosphorous (4.0 mg/dl vs. 6.5 mg/dl). In spite of the observed increase in protein and phosphorus intake seen in patients on SDHD, phosphate binder requirements and serum phosphorus levels are generally stable to decrease although this effect is strongly dependent on the frequency and overall treatment time.

A systematic review of the effect of nocturnal hemodialysis on blood pressure, left ventricular hypertrophy, anemia, mineral metabolism, and health-related quality of life

BACKGROUND

Nocturnal hemodialysis is a novel form of dialysis where patients perform dialysis 6 nights per week while they sleep. Multiple publications report significant improvements in selected clinical outcomes, although the strength of these results is limited by shortcomings in study design. A systematic review of the current available literature was undertaken to examine the effect of nocturnal hemodialysis on key health outcomes.

METHODS

An inclusive search of medical databases was undertaken to identify all nocturnal hemodialysis studies. These results were manually reviewed for relevance to nocturnal hemodialysis and its impact on the following predefined health outcomes: blood pressure control, left ventricular hypertrophy, anemia, mineral metabolism, and health related quality of life. Case reports, short-term studies (<4 weeks), studies without comparator groups, and studies not reporting data in a quantitative fashion were excluded. The results of the remaining studies were reported in tabular format.

RESULTS

Of the initial 270 studies identified, only 14 met inclusion/exclusion criteria. No studies examining the impact of nocturnal hemodialysis on mortality were identified. All studies reported improved blood pressure control after conversion to nocturnal hemodialysis. Data regarding the other health outcomes of interest revealed mixed results.

CONCLUSION

Nocturnal hemodialysis is a potential alternative to conventional intermittent hemodialysis. Before significant resources are invested in initiating nocturnal hemodialysis programs, further data on mortality and cardiovascular morbidity, preferably from randomized clinical trials, are required.

Allergic contact dermatitis and eosinophilia in association with a hemodialysis cannula

After starting daily hemodialysis (HD) therapy, 2 patients experienced pruritic, erythematous, papular eruptions at their arteriovenous fistula sites. Both patients also developed systemic eosinophilia, with eosinophil counts from 1.0 to 4.4 x 10(9) . In all other respects, the patients were well and both had a subjective improvement in their quality of life. Results of initial investigations to rule out the possibility of parasites, collagen vascular disease, and myeloproliferative disorders were negative in 1 patient. Subsequent patch testing in both patients was positive for allergic contact dermatitis secondary to the epoxy resin used in their blunt HD needles.

Management of anemia with quotidian hemodialysis

BACKGROUND

Most patients with end-stage renal disease have chronic anemia caused by inadequate erythropoietin (EPO) synthesis and require therapy with exogenous EPO to maintain recommended hematocrit and hemoglobin levels.

METHODS

The London Daily/Nocturnal Hemodialysis Study compared anemia control among patients on either short daily, long nocturnal, or conventional thrice-weekly hemodialysis (HD) therapy. Patients were administered iron, either orally (900 mg/d) or intravenously (50 to 125 mg every 1 to 4 weeks), to maintain serum ferritin levels at greater than 45 ng/mL (100 microg/L) or transferrin saturations greater than 20%. EPO was administered by subcutaneous injection at frequencies ranging from twice weekly to once every second week to maintain hemoglobin levels within the target range of 11 to 12 g/dL (110 to 120 g/L).

RESULTS

Both the daily HD and nocturnal HD study groups showed increased hemoglobin levels at later times compared with baseline levels, although only nocturnal HD patients had a statistically significant increase in hemoglobin levels at 18 months (11.94 g/dL [119.4 g/L] versus 10.95 g/dL [109.5 g/L] at baseline; P = 0.047). Both the daily HD and control groups showed a trend for decreased EPO dose requirements at later times compared with baseline, although these decreases were not statistically significant. The nocturnal HD group showed increased EPO dose requirements, although not statistically significant.

CONCLUSION

Quotidian HD is associated with an increased quantity of blood loss that can account for some of the increased requirements in EPO dose. Additional studies with larger numbers of patients are needed to fully elucidate the effects of quotidian HD on anemia.

Volume control and blood pressure management in patients undergoing quotidian hemodialysis

BACKGROUND

Hypertension and interdialytic weight gain are associated with left ventricular hypertrophy (LVH), an important predictor of cardiovascular mortality in hemodialysis (HD) patients.

METHODS

In the London Daily/Nocturnal Hemodialysis Study, a group of patients receiving quotidian HD, either short daily (n = 11) or long nocturnal (n = 12), were followed for up to 18 months. Patients were assessed for effects of quotidian HD therapy on blood pressure, interdialytic weight gain, extracellular fluid volume (ECFV), intensity of antihypertensive therapy, and homocysteine levels.

RESULTS

Significant reductions in predialysis mean arterial blood pressure were observed in the daily HD group at 6 months (P < 0.04) and in the nocturnal HD group at 9 months (P < 0.03); these improvements persisted throughout the study period. The daily HD group had a 60% reduction in mean number of antihypertensive tablets per day at 1 month and an 8.8-fold reduction by 18 months. Nocturnal HD patients experienced a 3.3-fold reduction, and control patients, a 1.4-fold increase in mean number of tablets per day by 18 months. By 3 months, the daily HD group showed a significant decrease in interdialytic weight gain (P < 0.0005) and lower ECFV than controls (P < 0.05). The nocturnal HD group had a transient, but significant, increase in interdialytic weight gain at 6 and 15 months (P < 0.05) and no difference in ECFV compared with controls, suggesting a different mechanism of blood pressure control. Homocysteine levels were significantly lower for both quotidian HD groups compared with conventional HD patients.

CONCLUSION

Quotidian HD is a promising therapy with potent antihypertensive effects, resulting in improved blood pressure control. This, together with improved homocysteine levels, may be beneficial in the long term with regard to cardiovascular mortality.

Clinical outcome of daily dialysis

Dialysis patients are prone to malnutrition, which may be counteracted by daily home hemodialysis (DHHD, 6 times a week) due to improved clinical outcome and quality of life. Eleven patients were treated with DHHD during 18 months, after a run-in period with three dialysis sessions a week. The total weekly dialysis dose was kept constant during the first 6 months of DHHD, whereupon it was allowed to increase. KT/V was 3.1 +/- 0.5 at baseline, 3.2 +/- 0.5 after 6 months and 4.0 +/- 0.8 at 18 months. Blood pressure decreased from 142 +/- 19/83 +/- 8 to 130 +/- 25/79 +/- 9 mmHg with a more than 50% reduction in antihypertensive medication. Potassium did not change, but potassium binding resins could be stopped almost completely. Bicarbonate increased from 20.6 +/- 3.3 to 23.1 +/- 2.6 mEq/L after 18 months. Patients with a protein intake of less than 1.0 g/kg/d showed a greater increase in body weight (62.3 +/- 6.0 to 65.5 +/- 3.7, P: < 0.05) and normalized protein catabolic rate (nPCR) (0.87 +/- 0.08 to 1.25 +/- 0.36, ns) than patients with acceptable protein intake (>/=1.0 g/kg/d). Phosphate decreased, though not significantly, especially in the latter group. Erythropoietin dose could be reduced from 6400 +/- 5400 U/L at baseline to 5100 +/- 4000 U/L at 18 months. Quality of life improved significantly, especially with to respect to physical condition and mental health. The DHHD markedly improves hemodynamic control and quality of life. Overall nutritional parameters did not change, except cholesterol. Patients with a low protein intake, however, showed a significant increase in body weight, and a greater rise in nPCR.