Hospital admissions over weekends have been associated with worse outcomes in a variety of patient populations. The cause for this remains unclear. Authors of a recent study in the American Journal of Kidney Diseases investigated this question by examining the mortality of end-stage renal disease (ESRD) patients on weekends. They found that maintenance dialysis patients admitted on weekends have increased mortality rates and longer lengths of stay compared with those admitted on weekdays. Dr. Ankit Sakhuja (AS), corresponding and first author, discusses this topic with Dr. Kellie Calderon (eAJKD), eAJKD Advisory Board member.

eAJKD: Your work is the first to examine the mortality of ESRD patients based on the hospital admission day of the week. What was your inspiration for this research?

AS: The increased “weekend mortality” has been shown in a lot of acute conditions. This has previously been studied in the general population. We focused on maintenance dialysis patients who are a fragile subgroup of patients. It is important for nephrologists and patients to understand the outcomes of ESRD patients depending on their day of admission, weekday versus weekend.

eAJKD: Please describe how you retrospectively identified chronic hemodialysis patients while excluding those with CKD stage 5 not on dialysis, as well as patients requiring acute hemodialysis?

AS: There is an ICD-9 code for ESRD patients (585.6) that we used. We did not use 585.5 (the code for CKD5). Additionally, we looked at patients who might have been coded for hemodialysis or peritoneal dialysis, but excluded those with any acute kidney injury codes.

eAJKD: Can you summarize your findings?

AS: There were around 700,000 admissions on weekends versus approximately 2,500,000 on weekdays. Unadjusted all-cause in-hospital mortality was 40,666 (5.8%) for weekend admissions in comparison to 138,517 (5.4%) for weekday admissions (statistically significant). Patients admitted on weekends were less likely to be discharged to home, had longer hospital stays, and had shorter times to death compared with those admitted on weekdays, in adjusted analysis.

eAJKD: You claim a difference in mortality rates with results of 5.4% versus 5.8%. Were you surprised that this seemingly small numerical difference achieved statistical significance?

AS: Not really. This is a huge database in which the smallest change in percentage can be statistically significant. What was striking was that there was an increase in absolute risk; it comes to about 1 in 250 based on this 0.4% difference. Hence, for every 250 admissions over weekends, there is probably one excess mortality in this population.

eAJKD: Most of us work on weekends. What would you like someone to take away from your article?

AS: When patients who require maintenance hemodialysis are admitted to the hospital, we should remember they are a very fragile population. When admitted on weekends, they tend to have higher mortality. Reasons for this are unclear. It has been postulated that staffing patterns and/or availability of procedures over weekends might be potential contributors. Additional studies are needed to specifically identify why this happens. Our study does not provide an answer to this question, but it shows that there might be a place for further research and improvement.

To view the article abstract or full-text (subscription required), please visit AJKD.org.