Association of Weekend Admission and Weekend Discharge with Length of Stay and 30-Day Readmission in Children’s Hospitals
BACKGROUND: Worse outcomes among adults presenting for/receiving care on weekends (ie, “the weekend effect”) have been observed for many diseases. However, little is known about the overall impact of the weekend effect in hospitalized children.
OBJECTIVE: To determine the association between weekend admission and length of stay (LOS) and between weekend discharge and 30-day all-cause readmission.
METHODS: We conducted a retrospective, cross-sectional study of children hospitalized between October 1, 2014 and September 30, 2015 using the Pediatric Health Information System. Birth hospitalizations and planned procedures were excluded. We used generalized linear mixed modeling to assess the independent association between weekend admission and LOS and weekend discharge and readmission risk.
RESULTS: Among 390,745 hospitalizations across 43 hospitals, the median LOS was 41 hours (interquartile range [IQR] 24-71) and the 30-day readmission rate was 8.2% (IQR 7.2-9.4). We observed no association between weekend admission and LOS (adjusted LOS [95% CI: weekend 63.70 [61.01-66.52] hours vs weekday 63.40 [60.73-66.19] hours, P = .112). Weekend discharge was associated with slightly increased odds of readmission compared with weekday discharge (adjusted probability of readmission [95% CI]: weekend 0.13 [0.12-0.13] vs weekday 0.11 [0.11-0.12], P < .001) but was variable among individual hospitals. Patient characteristics (ie, number of chronic conditions) were more strongly associated with LOS and readmission risk than weekend admission or discharge.
CONCLUSIONS: Patient-level factors (ie, clinical and demographic characteristics) are more indicative of longer LOS and readmission risk than weekend admissions or discharges. The overall impact of the weekend effect across children’s hospitals was minimal.
© 2018 Society of Hospital Medicine
Main Exposures
No standard definition of weekend admission or discharge was identified in the literature.33 Thus, we defined a weekend admission as an admission between 3:00
Main Outcomes
Our outcomes included LOS for weekend admission and 30-day readmissions for weekend discharge. LOS, measured in hours, was defined using the reported admission and discharge times. Readmissions were defined as a return to the same hospital within the subsequent 30 days following discharge.
Patient Demographics and Other Study Variables
Patient demographics included age, gender, race/ethnicity, payer, and median household income quartile based on the patient’s home ZIP code. Other study variables included presence of a complex chronic condition (CCC),34 technology dependence,34 number of chronic conditions of any complexity, admission through the emergency department, intensive care unit (ICU) admission, and case mix index. ICU admission and case mix index were chosen as markers for severity of illness. ICU admission was defined as any child who incurred ICU charges at any time following admission. Case mix index in PHIS is a relative weight assigned to each discharge based on the All-Patient Refined Diagnostic Group (APR-DRG; 3M) assignment and APR-DRG severity of illness, which ranges from 1 (minor) to 4 (extreme). The weights are derived by the Children’s Hospital Association from the HCUP KID 2012 database as the ratio of the average cost for discharges within a specific APR-DRG severity of illness combination to the average cost for all discharges in the database.
Statistical Analysis
Continuous variables were summarized with medians and interquartile ranges, while categorical variables were summarized with frequencies and percentages. Differences in admission and discharge characteristics between weekend and weekday were assessed using Wilcoxon rank sum tests for continuous variables and chi-square tests of association for categorical variables. We used generalized linear mixed modeling (GLMM) techniques to assess the impact of weekend admission on LOS and weekend discharge on readmission, adjusting for important patient demographic and clinical characteristics. Furthermore, we used GLMM point estimates to describe the variation across hospitals of the impact of weekday versus weekend care on LOS and readmissions. We assumed an underlying log-normal distribution for LOS and an underlying binomial distribution for 30-day readmission. All GLMMs included a random intercept for each hospital to account for patient clustering within a hospital. All statistical analyses were performed using SAS v.9.4 (SAS Institute, Cary, North Carolina), and P values <.05 were considered statistically significant.
RESULTS
We identified 390,745 hospitalizations that met inclusion criteria (Supplementary Figure 1). The median LOS among our cohort was 41 hours (interquartile range [IQR] 24-71) and the median 30-day readmission rate was 8.2% (IQR 7.2-9.4).
