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Hospitalization remains one of the greatest burdens in the dialysis patient population. According to the United States Renal Data System (USRDS), the rate of hospital admission in dialysis patients with Medicare fee-for-service coverage during 2017 was 1750 admissions per 1000 patient-years. Although this rate of hospital admissions is modestly lower than the corresponding rate 15 years earlier, it has exhibited little movement during the most recent 5 years of data collection. With respect to cumulative duration of hospitalization, the rate of hospitalized days in dialysis patients with Medicare fee-for-service coverage in 2017 was 11.2 days per patient-year. Interestingly, this rate translates to roughly 45 hospitalized minutes per calendar day. From that perspective, the human toll of hospitalization on dialysis patients and their families is plainly evident.1
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The human toll is rivaled by the economic toll. Again, according to the USRDS, cumulative Medicare Parts A, B, and D expenditures among dialysis patients with Medicare coverage during 2017 was $90,549 per patient-year. Of this total, $27,517 were attributable to inpatient facility payments and $3207 were attributable to physician payments in in-patient settings. Furthermore, another $3482 were attributed to skilled nursing facility payments, which are almost always subsequent to hospital discharge.1 Therefore, between 35% and 40% of all Medicare spending in the dialysis patient population is connected to hospitalization and post-acute care. As the cost of outpatient dialysis treatment is relatively fixed on a per-annum basis, it is clear that any serious attempt at reducing spending in the dialysis patient population begins—and possibly ends—with efforts aimed at lower hospitalization risk.
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Whether home hemodialysis (HHD) can alter hospitalization risk remains fundamentally unclear. Of course, the dominant prescriptions of HHD vary from one country to another. In New Zealand, Australia, and Canada, where HHD constitutes a larger share of the dialytic modality mix than in the United States, thrice-weekly treatment is common.1–3 In both Australia and New Zealand, roughly half of HHD patients dialyze three times per week. However, only 20% of HHD patients in Australia and New Zealand accumulate less than 15 hours of treatment per week.4 Thus, HHD is characterized by an increase in the cumulative duration of treatment, even when the frequency of treatment is unaltered. Extending the duration of treatment clearly lowers the ultrafiltration rate and likely increases the total removal of middle molecules, but if the frequency of treatment is unaltered, the long interdialytic gap and its associated morbidity may be unaddressed.5,6 This may have important consequences for hospitalization risk. In the United States, the contemporary application of HHD is dominated by low-flow dialysate, so HHD and frequent hemodialysis (HD) (i.e., treatment for >3 sessions per week) are tightly connected.7 On the other hand, utilization of nocturnal hemodialysis (NHD) has greatly lagged utilization of diurnal HD. In the home setting, diurnal HD typically involves four, five, or six treatments per week, at a duration between 150 and 200 minutes ...