Study: Weekend admissions for ESRD associated with high mortality

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From Medscape Medical News
Weekend Admissions for ESRD Associated with High Mortality

Nancy A. Melville

November 26, 2010 (Denver, Colorado) — Patients with end-stage renal disease (ESRD) who are admitted to the hospital on the weekend have higher rates of mortality than those admitted during the week, according to a study presented here at Renal Week 2010: American Society of Nephrology 43rd Annual Meeting.

A retrospective case–control analysis of estimated admissions of patients with ESRD was conducted as part of the Nationwide Inpatient Sample from 2007. The researchers found that the mortality rate among patients admitted on weekends was 17% higher than among those admitted on weekdays (odds ratio, 1.17; 95% confidence interval [CI], 1.11 - 1.24).

The time for patients to receive dialysis was 0.29 days longer (nearly a third of a day) on weekends than on weekdays (95% CI, 0.21 - 0.36).

Of the 836,550 estimated admissions for patients 18 years or older with ESRD, 19.7% occurred on a weekend. Researchers calculated the odds ratios for all-cause in-hospital mortality and the use of hemodialysis on weekends, adjusting for age, sex, race, patient comorbidities, and hospital characteristics.

ESRD patients are commonly admitted to the hospital with acute-care issues such as infection or electrolyte disturbances; however, hemodialysis services and manpower are often limited on weekends. Consequently, patients with acute renal failure can have poor outcomes when seeking treatment on weekends.

"Our study highlights poor outcomes for patients with ESRD admitted over the weekend," said coauthor Ankit Sakhuja, MD, a third year resident in internal medicine at The Medical College of Wisconsin, Milwaukee.

He noted that the leading cause of death was infection.

The research team found 1 exception to the increased weekend mortalities: ESRD patients who were admitted to the intensive care unit (ICU). "Other research suggests that the weekend effect likely does not exist among ICU patients," Dr. Sakhuja said.

Because the study was retrospective, the researchers could not determine a specific cause for the weekend effect. "We can say, however, that ESRD patients do have higher mortality on weekends," Dr. Sakhuja noted.

Although weekend admissions have been previously associated with poorer outcomes, the study underscores the fact that ESRD patients are particularly at risk, said session moderator Susan Hedayati, MD, assistant professor in internal medicine at the University of Texas Southwestern Medical School in Dallas.

"Worse clinical outcomes have been reported for weekend admissions in patients with other diseases, such as increased length of hospital stay and mortality in patients presenting with acute ischemic stroke or congestive heart failure," said Dr. Hedayati.

"Unfortunately, ESRD patients disproportionately suffer from such cardiovascular diseases, so the results of this study are not surprising. . . . However, even after controlling for comorbid medical conditions, weekend admission was still associated with an increased risk of death in Dr. Sakhuja's study," she explained.

Joachim H. Ix, MD, MAS, FASN, assistant professor of medicine at the University of California at San Diego and medical director of the dialysis unit at Veterans Affairs San Diego Healthcare System, speculated that changes in dialysis frequency, and subsequent fluid gain, could play a role in the higher weekend mortality rates.

"Rather than dialysis every 48 hours, which is characteristic of mid-week dialysis, it is typical for . . . [a] 72-hour period between dialysis sessions to occur over the weekend," he explained.

"In light of the recent findings that more frequent dialysis is associated with lower death or progression of left ventricular mass, another possibility is that greater fluid gain and associated cardiovascular consequences over the weekend may be contributing to the admissions and associated outcomes," Dr. Ix observed.

"Moving forward, future studies should evaluate the admitting diagnosis and the intensity of care for weekend vs weekday admissions to identify potentially modifiable factors," he said.

Dr. Sakhuja, Dr. Hedayati, and Dr. Ix have disclosed no relevant financial relationships.

Renal Week 2010: American Society of Nephrology 43rd Annual Meeting. Abstract TH-FC045. Presented November 18, 2010.

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