Outcomes are Worse for Dialysis Admissions During Weekends

By Ankit Sakhuja, MD, and Sankar Navaneethan, MD, MPH

Hospital admissions during weekends have been associated with unfavorable outcomes, especially for acute diagnoses such as myocardial infarction, stroke and gastrointestinal bleeding. The postulated reasons for the disparity in outcomes include inherent differences in staffing and availability of facilities and procedures between weekdays and weekends.

The literature that supports worse outcomes for patients admitted during weekends has been limited mostly to those admitted with acute diagnoses as described above; however, our group recently demonstrated that patients on maintenance dialysis admitted over weekends have worse outcomes even after adjusting for admitting diagnoses common to this group of patients. Using the Nationwide Inpatient Database (NIS), we examined data from more than 3 million adult, nonelective inpatient admissions over a five-year period (2005-2009). Information regarding patients’ age, sex and race, and primary payer and hospital characteristics such as hospital bed size, teaching status and hospital region are provided in the NIS database. These characteristics were used as covariates in multivariable regression analysis to assess independent predictors of mortality. Comorbidity burden was adjusted using the Charlson comorbidity index. Common primary diagnoses for hospitalization of maintenance dialysis patients (cardiovascular diseases that included acute coronary syndrome, atrial fibrillation/flutter, heart failure and stroke, infections or access complications, gastrointestinal bleeding, hypertensive emergency, and hyperkalemia) were also adjusted for in this multivariable analysis.

Disparity remains even after adjustment

More than 21 percent of total admissions occurred during weekends. Our group found that patients admitted during weekends had higher all-cause inpatient mortality compared with those admitted over weekdays (5.8 percent vs. 5.4 percent; p < 0.001). This difference translates into one excess death for every 250 weekend admissions. After multivariable adjustment, those admitted over weekends were 6 percent more likely to die than those admitted over weekdays (odds ratio: 1.06; 95 percent confidence interval 1.01-1.10). Subgroup analysis revealed that excess mortality for weekend admissions was present regardless of age, sex, race, primary payer or hospital bed size.

Although this was a retrospective study, it brings to light an important issue: namely, the discrepancy in outcomes between patients who are admitted during weekends vs. those admitted on weekdays. This is the first study that shows that the disparity in outcomes between weekend and weekday admissions may not be limited to acute diagnoses. Considering that patients on maintenance dialysis have a much higher admission rate than nondialysis patients, this finding assumes even greater importance. This study was not designed to examine the potential reasons for these disparities. Further research is needed to better understand the factors responsible for this “weekend effect” and to help improve patient outcomes.

Dr. Navaneethan is a Physician in the Department of Nephrology and Hypertension at Cleveland Clinic’s Glickman Urological & Kidney Institute.

Dr. Sakhuja completed his nephrology fellowship with Cleveland Clinic’s Glickman Urological & Kidney Institute.