A kinetic survey of US hemodialysis prescriptions

Recent reports indicate increasing mortality correlated to reduced treatment time (t) in hemodialysis (HD) patients. HD prescriptions for 101 patients visiting our unit were subjected to kinetic analysis to assess the amount of dialysis prescribed (Kt/V) and its relationship to t. The analysis showed (1) 98% of the prescriptions were empirical; (2) Kt/V was strongly correlated to protein intake (normalized protein catabolic rate [NPCR], g/kg/d), r = 0.50, N = 101; (3) Kt/V was strongly correlated to t, y = 0.50 + 0.54x, r = 0.54, and fell below 1 when t less than or equal to 3.5 hours; (4) a prescription flux deficit appeared and increased exponentially as t fell below 3.7 hours. These results suggest that in clinical practice, t is individualized as a function of predialysis BUN and is reduced when BUN is low due to low NPCR because of a perceived need for less dialysis. Because of this practice, reduced t is often associated with inadequate dialysis, and kinetic modeling of the interrelationship between blood urea nitrogen (BUN), NPCR, and Kt/V is required to assure adequate dialysis with reduced t.