Phosphorus balance and mineral metabolism with 3h daily hemodialysis

Abstract

Poor control of mineral metabolism is independently associated with mortality in patients receiving hemodialysis. We analyzed data from a 12-month, prospective, non-randomized, controlled study of daily hemodialysis (DHD) (six sessions/week 3 h each) (n=26) vs conventional hemodialysis (CHD) (three sessions/week 4 h each) (n=51) for achievement of mineral metabolism goals and we performed a substudy of weekly dialytic phosphorus removal in DHD vs CHD. Phosphorus control was superior in the DHD group (% change from baseline to end-of-study -27+/-30% vs +7%+/-35% in the CHD group, P=0.0001). Percentage of patients using phosphate binders decreased from 77 to 40% among subjects on DHD, whereas these parameters did not change (76 vs 77%) in the CHD group (P=0.03 by Breslow-Day test for homogeneity of the odds ratios). Weekly mean phosphorus removal was higher in the DHD group (2452+/-720 mg/week vs 1572+/-366 mg/week, P=0.04). Mean normalized protein catabolic rate increased (0.90+/-0.43-1.22+/-0.26 g/kg/day, P=0.0013). DHD was also associated with an increase in the percent of subjects achieving three or more mineral metabolism goals (for phosphorus, calcium x phosphorus and parathyroid hormone) (15 vs 46%, P=0.046). In conclusion, DHD improves phosphorus control by increasing dialytic phosphorus removal while maintaining nutritional status and reducing the use of phosphate binders. The net effect allows for improved achievement of mineral metabolism goals.

Left Ventricular Hypertrophy

“…Therefore, a veritable wall is erected, below which the phosphorus level cannot drop without increasing dialytic removal, unless the patient risks malnutrition. We provide evidence that conventional hemodialysis removes only 1572 mg/wk when the serum phosphorus is well controlled, whereas with similar predialysis phosphorus levels, short daily hemodialysis removes approximately 2452 mg of phosphorus in a week (39). Therefore, at lower levels of predialysis serum phosphorus, conventional hemodialysis has very limited phosphorus removal.…”

“…Phosphate efflux then falls off, but remains at roughly half the initial value at the end of the treatment despite stable serum phosphorus levels. Recently, we directly measured serum phosphorus removal in a group of conventional and short daily hemodialysis patients with good control of serum phosphorus (predialysis phosphorus 4.2 to 4.5 mg/dl), and we found that daily dialysis removes significantly more phosphorus than conventional and that conventional dialysis removes only 1573 mg of phosphorus, when predialysis phosphorus levels are well controlled (39). What is clear is that conventional dialysis does not remove sufficient phosphorus to achieve good control of serum phosphorus in the majority of dialysis patients.…”

Activated vitamin D attenuates left ventricular abnormalities induced by dietary sodium in Dahl salt-sensitive animals

“…Adult chronic hemodialysis patients at the Texas Diabetes Institute (San Antonio, TX) were enrolled in a 12-month study to assess the effects of hemodialysis on cardiac function (41). Baseline and 12-month transthoracic echocardiograms were performed by using standard techniques and reviewed by two independent cardiologists blinded to the examination date and therapy status.…”

In-center Nocturnal Hemodialysis

“…Long intermittent HD, performed for 8 h during the day, three times per week, has been associated with better BP control and a lower standardized mortality rate (5). Short daily HD, performed for at least 2 h, five to six times per week, may improve phosphate and BP control (6,7). Home nocturnal HD (HNHD), performed for 7 to 8 h, five to seven nights per week, can normalize phosphate levels without need for binders (8), improve BP control with few or no antihypertensive medications (9), restore impaired left ventricular systolic function (10) and vascular function (11,12), improve left ventricular mass (13), and stabilize coronary artery calcification (14).…”