Mortality, Length of Stay, and Cost of Weekend Admissions

Association of Hospital Mortality With Initiation of Mechanical Ventilation on a Weekend: A Retrospective Cohort Study

RATIONALE

Increased mortality in patients admitted to hospitals on weekends is a well-described phenomenon labeled the "weekend effect." Studies evaluating the weekend effect in intensive care units (ICUs) have arrived at conflicting results. Identifying a weekend effect for critically-ill patients may inform clinical care pathways and resource allocation.

OBJECTIVES

Determine the association of initiation of mechanical ventilation (MV) upon admission on a weekend versus weekday with hospital mortality.

METHODS

We conducted a retrospective cohort study of non-surgical adult patients using the California Patient Discharge Database from 2018 to 2019. We identified MV initiated on the day of admission and diagnoses using discharge billing codes. The primary exposure was admission and initiation of MV on a weekend versus weekday and the primary outcome was hospital mortality. Hierarchical logistic regression was used to determine the association between hospital mortality and MV initiation timing, adjusting for case-mix.

RESULTS

Among 90 288 admissions in 2018 and 2019 meeting inclusion criteria, 24 771 (27.5%) had MV initiated on weekends, while 65 517 (72.6%) had MV initiated on weekdays. Patient demographics and comorbidities were similar between groups. Chronic alcohol and substance use disorders, and acute intoxications and traumas were more prevalent among patients with MV initiated on weekends. No difference in hospital mortality was observed with initiation of MV on weekends versus weekdays (23.1% vs 22.8%, ARD = 0.3%, aOR = 1.02, 95% CI 0.98, 1.07).

CONCLUSIONS

Contrary to prior studies, no increased mortality was observed among newly admitted patients initiated on MV on weekends compared to weekdays. While weekend effects may exist in other settings, newly admitted patients likely have MV initiated in the emergency department or ICU, which tend to have more consistent staffing levels. Further research is needed to determine if care patterns in these units could be used as a model for units where weekend effects continue to impact outcomes.

Weekend Effect on Mortality, Access to Renal Replacement Therapy, and Other Outcomes Among Patients With End-Stage Renal Disease: A Retrospective Analysis of the Nationwide Inpatient Sample

BACKGROUND

A large body of research has been conducted on the "weekend effect," which is the reportedly increased risk of adverse outcomes for patients admitted to the hospital on weekends versus those admitted on weekdays. This effect has been researched in numerous patient populations, including sub-populations of end-stage renal disease (ESRD) patients, with varying conclusions.

OBJECTIVES

To assess whether differences in in-hospital mortality, access to renal replacement therapy (RRT), time to RRT, and other important outcomes exist in patients with ESRD or patients on RRT admitted on the weekend versus weekdays.

DESIGN AND SETTING

A retrospective cohort study was conducted using the 2018 Nationwide Inpatient Sample. Patients were included if they were adults with a principal or secondary diagnosis of ESRD or if they were admitted with a diagnosis related to initiation, maintenance, or complications of RRT. Patients admitted between midnight Friday and midnight Sunday were classified as weekend admissions. Primary outcome measurements included in-hospital mortality, in-hospital dialysis (peritoneal dialysis, hemodialysis, and continuous RRT), and renal transplantation (TP). Secondary outcomes included length of hospital stay (LOS) and total hospitalization charges.

RESULTS

The study included 1,144,385 patients who satisfied the inclusion criteria. Compared with patients admitted on weekdays, patients with ESRD admitted on weekends had 8% higher adjusted odds of in-hospital mortality (OR: 1.08; 95% CI: 1.03-1.13; p = 0.002), 9% lower adjusted OR of any RRT over the weekend than on weekdays (OR: 0.91; 95% CI: 0.89-0.93; p = 0.000), lower RRT rates (within 24 hours) (adjusted OR: 0.71; 95% CI: 0.70-0.73; p = 0.000), higher odds of renal TP (adjusted OR: 1.32; 95% CI: 1.20-1.45; p = 0.000), and higher hospitalization charges (mean adjusted increase: $1451; p = 0.07).

LIMITATIONS

The limitations of the study include the use of retrospective data and an administrative database.

CONCLUSION

Compared with weekday admissions, patients with ESRD admitted on weekends had higher odds of mortality, higher mean hospitalization charges, and higher odds of renal TP. They had lower overall RRT rates, and a longer time to first RRT. However, the average LOS was similar for both weekend and weekday admissions.

Severity of illness and the weekend mortality effect: a retrospective cohort study

Background

Weekend admission to the hospital has been found to be associated with higher in-hospital mortality rates, but the cause for this phenomenon remains controversial. US based studies have been limited in their characterization of the weekend patient population, making it difficult to draw conclusions about the implications of this effect.

Methods

A retrospective cohort study, examining de-identified, patient level data from 2015 to 2017 at US academic medical centers submitting data to the Vizient database, comparing demographic and clinical risk profiles, as well as mortality, cost and length of stay, between weekend and weekday patient populations. Between-group differences in mortality were assessed using the chi-square test for categorical measures and Wilcoxon rank-sum test for continuous measures. Logistic regression models were used to test the multivariate association of weekend admission and other patient-level factors with death, LOS, etc.

Results

We analyzed 10,365,605 adult inpatient encounters. Within the weekend patient population, 30.6% of patients were categorized as having either a major or extreme risk of mortality on admission, as compared to 23.7% on weekdays (p < 0.001). We found a significantly increased unadjusted mortality rate associated with weekend admission (OR 1.46; 95% CI 1.45–1.47) which was substantially attenuated after adjusting for disease severity and other demographic covariates, though remained significant (OR 1.05; 95% CI 1.04–1.06). In the subgroup of non-elective admissions, the unadjusted OR for death was 1.14 (95% CI 1.13–1.15), and the adjusted OR was 1.04 (95% CI 1.03–1.05). Weekend admission was associated with a longer median LOS (4 vs 3 days in the weekday group; p < 0.01), but a lower median cost ($8224 vs $9999 dollars in the weekday group; p < 0.01).

Conclusion

The patient population admitted on weekends is proportionally higher risk than the population admitted on weekdays, and the observed weekend mortality effect is largely attributable to this risk imbalance.