Patients on hemodialysis for more than three months at 42% higher risk of death between 6 am and noon.
Prevalent hemodialysis patients—those on hemodialysis for more than three months— may be more likely to die in the morning than any other time of day, a study suggests.
In these patients, 24.8% more deaths occurred from 4:01 am to noon than would be expected by chance alone. The risk of dying during these hours was 42% greater compared with the rest of the day, investigators reported in the American Journal of Kidney Diseases (2008;51:53-61). The researchers did not gather information on causes of death.
They observed no increase in the frequency of deaths in the morning hours among patients on hemodialysis for three months or less (incident hemodialysis patients).
The investigators, led by András Tislér, MD, PhD, of the B. Braun Avitum Nephrological Network and Semmelweis University in Budapest, Hungary, prospectively studied 873 hemodialysis patients who had died. The group included 459 prevalent and 414 incident hemodialysis patients for whom information about time of death was available.
The study also identified significant independent risk factors for morning death among prevalent hemodialysis patients. Being an outpatient increased that risk by nearly twofold. The presence of diabetes and the use of beta blockers were associated with a 72% and 62% increased risk. Time since the end of the last dialysis session also was a significant predictor of morning death risk.
That risk was 68% and 80% higher among patients for whom 25-48 and 49-72 hours, respectively, had elapsed since the end of the last dialysis session. The presence of a medical symptom during the last dialysis session was associated with a 47% reduced risk of morning death.
“To our knowledge, this is the first prospective study designed to examine prospectively the circadian variation of death in a hemodialysis population,” the authors wrote. “The lack of information for this topic is surprising given the high cardiovascular disease and mortality rates in these patients.”
In speculating why incident hemodialysis patients did not have an excess of morning deaths, they noted that a recent start of dialysis therapy may override or disrupt any underlying rhythmicity in the occurrence of death.
Previous studies have revealed a circadian variation in death risk in the non-dialysis population, with more cardiovascular events occurred between 6 am and noon.