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Summary of Impact of Daily Hemodialysis on Uremic Complications (ASN/ISN 2001)

Christopher Blagg, M.D., Professor of Medicine Emeritus, University of Washington, Seattle, WA.

This, one of the last sessions at the recent ASN/ISN World Congress on Nephrology, was important for those of us interested in daily hemodialysis.

Dr. Andreas Pierratos from Humber River, Ontario, Canada discussed renal osteodystrophy. With nocturnal hemodialysis, phosphate removal was twice that with conventional hemodialysis, on a free diet serum phosphate levels normalized within one to two weeks and phosphate binders were discontinued in all patients. Despite a free diet high in phosphate, 75% of patients required addition of sodium phosphate to the dialysate. Calcium phosphate product normalized in all patients and a tumerous extraosseus calcification in one patient dissolved. When nocturnal dialysis was first done, serial studies showed a decline in bone density and so dialysate calcium was then increased to 3.0 or 3.5 mEq/L or patients added calcium to the acid concentrate. With this, PTH levels were easily suppressed, and no new or increased arterial or soft tissue calcification was seen on annual soft tissue X-rays. Bone biopsies showed low turnover in 13 of 17 patients, but bone mass was normal in all but three of them. Three patients had hyperparathyroid bone disease and one had a mild lesion. Oversuppression of PTH may be an issue, but a high dialysate calcium is necessary to maintain or improve bone density.

With short daily hemodialysis, phosphate control is also better than with conventional hemodialysis. Reports vary, but predialysis phosphate may be reduced but this may be offset by increased appetite and dietary phosphate ingestion. The need for phosphate binders may also be reduced. Calcium phosphate product may also be decreased but PTH levels are unchanged. Bone biopsies in four patients before and after two years of daily short dialysis showed two of three patients with adynamic lesions that converted to mild osteitis fibrosa cystica, and a fourth patient with aluminum bone disease that improved, presumably because of stopping aluminum-containing supplements.

Professor Jules Traeger from Lyon, France, described the impact of short daily dialysis on nutrition and quality of life in twelve patients treated for one to four years after switching from three hours of hemodialysis three times weekly to two hours six times weekly. Initially some patients were malnourished with low serum albumin levels as a result of anorexia and low protein and calorie intake. All patients spontaneously increased their daily intake of protein and calories and their dry weight, body mass index and lean body mass all increased. Their anorexia disappeared and measures of quality of life showed improvements in all patients. These results were maintained long term. All patients tolerated the short daily regime extremely well and no patient wanted to return to a thrice weekly dialysis schedule.

Dr. George Ting from El Camino, California gave a very detailed summary of the economic consequences of daily hemodialysis, a treatment that is not feasible in the United States today with the present reimbursement system. Improved clinical outcomes with consequent cost savings have been found in all studies here and in Europe. These include decreased erythropoietin requirements, reduction or elimination of antihypertensive medications, and, in the case of nocturnal dialysis, elimination of phosphate binders. Blood access has not been a problem, and access survival may be better. The frequency of hospitalization and number of hospital days are reduced. These savings are offset by the cost of the increased number of dialyses and associated supplies, and, if dialyzing at home, the cost of one machine per patient, the cost of training, the possible increased cost of technical support and in some programs payment for a helper. With more frequent dialysis in the center there are impacts on staffing, turnaround time, scheduling a reduction in available dialysis slots and treatment capacity, and increased transportation needs. Incentives for patients include improved wellbeing and quality of life and, in the case of nocturnal dialysis freedom from scheduling, daytime freedom and better phosphate control. Disincentives are the increase in punctures and dialysis frequency and, in the home, added patient work and need for space for machine and supplies. Incentives for payors include the reduced global costs and better outcomes and improved quality of life.

In the El Camino program the estimated overall savings with six times weekly dialysis are some $4-5,000 per patient per year. Disincentives for payors include the uncertain economics, increased transportation costs for dialysis in the center and, for dialysis at home, the additional machine costs and the training costs. Incentives for providers are the patient benefits and, in the center, the increased number of dialyses resulting from less hospitalization and the fewer staff interventions as a result of improvement in patient wellbeing during dialysis. Disincentives include added costs of supplies, reduction in revenue from erythropoietin (unless under managed care) and pressures on staff with more dialyses each day. With a home program the disincentives include inadequate reimbursement for training and the increased costs for a machine, water treatment and supplies. So far, estimates are that global cost savings outweigh added costs by several thousand dollars per year. Dr. Ting concluded that the most important action now is for people to support HR 1759 and S 1303 the bills in Congress to provide a reimbursement mechanism for more frequent hemodialysis.

Dr. Roula Galland of Lyon, France discussed the regression of left ventricular hypertrophy and blood pressure control seen in ten patients, eight of whom were hypertensive, who were changed from four to five hours three times weekly to two to two and a half hours six times weekly. After one year the significant changes were lower mean blood pressure, lower left ventricular diastolic diameter, lower left ventricular mass index and lower interdialytic weight gain. Left ventricular diastolic diameter improved rapidly. At the latest follow-up these changes continued and the reductions in posterior wall thickness and interventricular wall thickness also became significant. There was a significant correlation between the reduction in interdialytic weight gain and left ventricular diastolic diameter and left ventricular mass index. Daily hemodialysis reduced interdialytic fluid overload and dry weight was more easily achieved. Left ventricular hypertrophy was reduced even in the patients who were not hypertensive. Increased frequency of dialysis seems to be the main factor in these improvements.

Dr. Oliver Zilch from Utrecht in the Netherlands discussed reduction of peripheral resistance and sympathetic activity after changing four hours of dialysis three times weekly to two hours six times weekly for six months in eleven patients and then returning to the original schedule for nine weeks in seven of the patients. Studies were done when taken off antihypertensive drugs. With six times weekly dialysis the statistically significant changes were that mean arterial pressure was reduced, cardiac output increased, peripheral vascular resistance decreased and muscle sympathetic nerve activity (peroneal nerve in bursts per minute) decreased. No change was seen in plasma rennin activity. The change in peripheral vascular resistance correlated strongly with the change in muscle sympathetic nerve activity. On returning to three times weekly dialysis there was a statistically significant reversal of all the changes and again plasma rennin activity was unchanged and the change in peripheral resistance correlated significantly with the muscle sympathetic nerve activity. Extracellular volume did not change in both groups. This study showed that increasing dialysis frequency to six times weekly results in a reduction in peripheral vascular resistance and suggests that this may be explained by a decrease in sympathetic activity.