Higher Mortality and Admissions after Long Interdialytic Gap

In patients receiving hemodialysis three times weekly, the 2-day gap between dialysis sessions is consistently associated with increased mortality and hospitalization rates, according to a study from the United Kingdom in Kidney International.

The study used data on 5864 patients from the UK Renal Registry from 2002 through 2006, linked to data on hospitalizations and deaths. The associations of these outcomes with the long (2-day) interdialytic gap were assessed, including the effects of different thrice-weekly schedules.

Hospitalization rates were higher after the 2-day gap: 2.4 per year, compared with 1.4 for the rest of the week. This difference was significant whether the thrice-weekly dialysis schedule began on Monday or Tuesday. The greatest increase was seen for admissions for fluid overload, or conditions associated with a high risk of fluid overload.

There was a similar increase in mortality after the 2-day gap: 20.5 versus 16.7 per 100 patient-years, rate ratio 1.22. This mainly reflected an increase in out-of-hospital deaths: rate ratio 1.59, compared with 1.06 for in-hospital deaths. The increase in mortality associated with the long interdialytic gap was limited to white patients.

These data from the UK are consistent with previous studies reporting increased mortality and hospitalization after the 2-day interdialytic gap. The increase in admission may be associated with an increase in fluid overload; the increase in out-of-hospital mortality may reflect an increased incidence of sudden death. The authors discuss the implications for measures to minimize interdialytic intervals or limit fluid overload [Fotheringham J, et al. The mortality and hospitalization rates associated with the long interdialytic gap in thrice-weekly hemodialysis patients. Kidney Int 2015; 88:569–575].