A Pragmatic Randomized Clinical Trial: Twice-weekly vs Thrice-weekly Incident hemoDialysis in Elderly Patients

End-stage kidney disease (ESKD) poses a substantial public health challenge, with the number of patients requiring renal replacement therapy (RRT) globally reaching 2.61 million in 2010 and projected to rise to 5.43 million by 2030. In Korea, the incidence of hemodialysis (HD) has also been gradually increasing. The increase in HD incidence in South Korea is significantly linked to the aging population. Korea is one of the most rapidly aging countries in the world and the age of dialysis patients is also increasing, with more than half over the age of 60.

HD has potential advantages over conservative management or peritoneal dialysis in older adults, however, guidelines for optimal HD for the elderly have not yet been established. Typically, patients receive HD three times a week, with only a small proportion of patients receiving less frequent dialysis. However, potential disadvantages such as hemodynamic stress, vascular access problems, bleeding, falls and economic cost should be considered in older adults with ESKD.

In elderly patients, it is often difficult to maintain a thrice-weekly HD schedule due to the presence of other medical conditions and the challenges of frailty. Elderly patients have shown poor outcome even after initiation of HD. A study by Santos et al. demonstrated a more than twofold increased risk of mortality at 6 months in patients older than 75 years compared to those younger than 75. Another study using Japanese National Dialysis Registry data revealed a 30% mortality rate in those aged over 80 years within 1 year after initiation of HD, with frailty being one of the most important factors associated with early death after initiation of HD. Excessive HD in elderly patients can lead to malnutrition, low blood pressure during dialysis, poor quality of life, depression, and stress due to physical and temporal activity restriction. The increased risk of falls in HD patients is also a serious problem.

Incremental initiation of HD involves starting HD at a lower intensity than the standard 4 hours thrice weekly and gradually increasing the frequency and duration of dialysis as kidney function declines. The decision to initiate patients on incremental HD can be made based on clinical parameters such as urine volume or residual kidney function, socio-economic factors such as financial limitations or insurance coverage, or lack of availability of dialysis services. Current guidelines recommend that twice weekly dialysis be performed in patients with kidney urea clearance greater than 3ml/min/1.73m2 or a urine output over 0.5 liter per day.

A systemic review and meta-analysis showed no difference in mortality, hospitalization rates, or quality of life between patients receiving incremental and conventional HD, with improved preservation of residual renal function and a reduction in dialysis cost with incremental HD. One randomized controlled trial (RCT) showed no difference in episodes of fluid overload or hyperkalemia, but an increased risk of hyperkalemia with incremental HD. Another study showed lower hospitalization rate in incremental HD compared to conventional dialysis. These studies demonstrate the need for a large RCT comparing incremental and conventional HD.