Mortality risks associated with emergency admissions during weekends and public holidays: an analysis of electronic health records

Abstract

SummaryBackgroundWeekend hospital admission is associated with increased mortality, but the contributions of varying illness severity and admission time to this weekend effect remain unexplored.MethodsWe analysed unselected emergency admissions to four Oxford University National Health Service hospitals in the UK from Jan 1, 2006, to Dec 31, 2014. The primary outcome was death within 30 days of admission (in or out of hospital), analysed using Cox models measuring time from admission. The primary exposure was day of the week of admission. We adjusted for multiple confounders including demographics, comorbidities, and admission characteristics, incorporating non-linearity and interactions. Models then considered the effect of adjusting for 15 common haematology and biochemistry test results or proxies for hospital workload.Findings257 596 individuals underwent 503 938 emergency admissions. 18 313 (4·7%) patients admitted as weekday energency admissions and 6070 (5·1%) patients admitted as weekend emergency admissions died within 30 days (p<0·0001). 9347 individuals underwent 9707 emergency admissions on public holidays. 559 (5·8%) died within 30 days (p<0·0001 vs weekday). 15 routine haematology and biochemistry test results were highly prognostic for mortality. In 271 465 (53·9%) admissions with complete data, adjustment for test results explained 33% (95% CI 21 to 70) of the excess mortality associated with emergency admission on Saturdays compared with Wednesdays, 52% (lower 95% CI 34) on Sundays, and 87% (lower 95% CI 45) on public holidays after adjustment for standard patient characteristics. Excess mortality was predominantly restricted to admissions between 1100 h and 1500 h (pinteraction=0·04). No hospital workload measure was independently associated with mortality (all p values >0·06).InterpretationAdjustment for routine test results substantially reduced excess mortality associated with emergency admission at weekends and public holidays. Adjustment for patient-level factors not available in our study might further reduce the residual excess mortality, particularly as this clustered around midday at weekends. Hospital workload was not associated with mortality. Together, these findings suggest that the weekend effect arises from patient-level differences at admission rather than reduced hospital staffing or services.FundingNIHR Oxford Biomedical Research Centre.

Excess mortality associated with weekend hospital admissions may be due to patient-level differences, rather than reduced staffing or services

“…In addition, patient behaviours in seeking treatment and receiving a diagnosis from other services outside the hospital may further explain the effect 2. These findings differ from existing research that explain the weekend effect as a result of decreased resources.…”

“…Examining 15 haematology and biochemistry tests that are commonly performed on admission, as well as three proxy measures of workload, Walker et al aimed to investigate possible explanations for the weekend effect among this patient population 2. Instead of using an administrative dataset, they used data from electronic health records representing 503 938 emergency admissions.…”

“…The researchers explain this finding from the decreased availability of outpatient services and more frail people presenting to a hospital during weekend days 2. Another explanation may be attributable to patients who ignore symptoms during the night, hoping that their discomfort will dissipate and seeking treatment during day hours when the symptoms fail to subside.…”

Non-surgical in-hospital mortality predictors: a multivariable regression analysis of 2,855,029 hospitalizations

“…Previous studies identified the "weekend effect," meaning that patients who are admitted to hospital at weekends have an increased mortality risk. [36][37][38][39] This may be due to a lower number of hospital employees working on those days, less experienced staff, longer time waiting to receive treatment, limited access to test results and diagnostic modalities, and serious condition of patients (only the sickest patients are admitted at weekends). However, not all studies showed increased in -hospital mortality in patients admitted to the hospital at weekends.…”

Diurnal variations in the quality of stroke care in Sweden

“…However, less is known about the underlying causes of these effects . A recent study on general emergency admissions found that the magnitude of the weekend effect was significantly reduced when adjusting for patient comorbidity and common blood tests, suggesting that differences in patient characteristics contribute …”