Boundaries of frequency and treatment time in conventional hemodialysis: Balancing convenience, economics, and health outcomes.

Since the inception of hemodialysis (HD) for patients with chronic kidney disease, the "perfect" dialysis prescription has remained elusive. Part of this may relate to the heterogeneity among populations, individual patients, and differences in access to health provision. The optimal balance between dialysis frequency and duration to achieve reductions in patient morbidity and mortality continues to be debated. The concept of dialysis adequacy originated from a post hoc mathematical analysis of the National Cooperative Study and has evolved to become a way of calculating dialysis dose and standardizing the dialysis prescription. In contrast, in its originally conceived sense, dialysis adequacy referred to the effective clearance of small solutes. Given the evolution of dialysis practice, we now aim to consider dialysis adequacy in a broader and more holistic manner particularly in view of our aging population and focus toward important patient-centered outcomes. While the traditional thrice weekly, HD regimen remains the default renal replacement modality, alternative strategies including short daily HD, long conventional HD, and long nocturnal HD are being widely implemented. We aim for optimal solute clearance, effective ultrafiltration to achieve normotension (while avoiding intradialytic symptoms) and maintenance of nutritional parameters all within the caveat that quality of life and autonomy are preserved.