Mortality higher after two days off from dialysis

Longer intervals between hemodialysis sessions are associated with higher mortality and hospital admissions, a new study found.

The study included more than 32,000 participants in the End-Stage Renal Disease Clinical Performance Measures Project. The patients received hemodialysis three times per week, so that they had one two-day interval of no dialysis every week. Researchers compared rates of death and hospital admission on the day after that break with rates on all other days. The results were published in the Sept. 22 New England Journal of Medicine.

During a mean follow-up of 2.2 years, the researchers found that days after the break were associated with higher all-cause mortality (22.1 vs. 18.0 deaths per 100 person-years; P<0.001), mortality from cardiac causes (10.2 vs. 7.5; P<0.001), infection-related mortality (2.5 vs. 2.1; P=0.007), mortality from cardiac arrest (1.3 vs. 1.0; P=0.004), and mortality from myocardial infarction (6.3 vs. 4.4; P<0.001). On that day, there were also more hospital admissions for myocardial infarction (6.3 vs. 3.9; P<0.001), congestive heart failure (29.9 vs. 16.9; P<0.001), stroke (4.7 vs. 3.1; P<0.001), dysrhythmia (20.9 vs. 11.0; P<0.001), and any cardiovascular event (44.2 vs. 19.7; P<0.001).

The findings confirm widespread clinical impressions that two-day intervals are associated with higher risks, the study authors said. The causes and effects cannot be definitely identified, but the researchers believe it unlikely that confounding could be responsible for the results.

In addition to the negative impact of the two-day interval on patients' health, the current setup of dialysis may be increasing health care costs more than the addition of an extra dialysis session would, the authors suggested. They called for a controlled trial of dialysis schedules.