Infrequent Dialysis: A Different Strategy to Incremental Dialysis

To the Editor:

With regard to your recent publication,1, 2 I should like to highlight the nosological and methodological differences between “incremental hemodialysis” and “infrequent hemodialysis.” Indeed, infrequent dialysis³ embraces the full range of therapeutic options implemented with a schedule of less than thrice-weekly hemodialysis sessions, ideally integrated by a moderately low-protein diet. Incremental dialysis4, 5 is a strict program implemented following assessment of uremic status in a predialysis outpatient setting through a synergic nephrological and nutritional approach aimed at achieving an excellent nutritional status and preserving diuresis with a glomerular filtration rate (GFR) ranging between 5 and 10 ml/min per 1.73 m².

Total weekly GFR should be calculated on the basis not only of urea clearance, but also taking into account the mean of urea/creatinine clearance.⁶ An incremental dialysis program may then be set up with the assistance of a skilled logistics team in charge of monitoring patient compliance and ensuring smooth running of the program. Initially, the Combined Diet Dialysis Program⁴ comprising once-weekly dialysis associated with a low-protein diet (0.6 g protein/kg per day) and administration of essential amino acids is implemented. On dialysis days, the patient is requested to consume a meal with approximately 1.4 g protein/kg per day per 1.73 m². The Combined Diet Dialysis Program represents a dialytic "bridge" of variable duration aimed at ensuring good metabolic state and promoting quality of life. Dialysis dose is established in line with the outcome of GFR in a proportionally inverse manner. Recent studies4, 7 have demonstrated a lower mortality for incremental dialysis than thrice-weekly dialysis, and, thanks to the contribution of phosphaturia, a neutral balance of input/output phosphoric pool compared with thrice-weekly hemodialysis patients who lose residual renal function early.⁸ Reduced contact with proinflammatory/pro-oxidative stimuli secondary to hemodialysis may enhance preservation of GFR. Residual renal function has long been underestimated⁹ in spite of the exceptional efficacy displayed in purifying protein-bound uremic toxins compared with other forms of dialysis10, 11; indeed, residual renal function may contribute toward establishing a phosphoric balance resulting in a reduction of cardiovascular damage and direct phosphatic lesions of the renal parenchyma.¹² Infrequent dialysis is indicated for use in patients maintaining a GFR <3 ml/min per 1.73 m², particularly smaller patients. With regard to both methods, however, the additional time spent on clinical assessment will be recouped using the Combined Diet Dialysis Program due to a two-thirds reduction in hemodialysis costs equivalent to an annual saving per patient of more than $22,000.