Risk factors associated with short term mortality changes over time, after arrival to the emergency department.

BACKGROUND: Preventing death is the most important outcome pursued in the Emergency Department. Prompt accurate assessment, followed by competent and efficient investigation and treatment is the recipe sought. Abnormal physiological measurements are common antecedents to deterioration and therefore a cornerstone in many risk stratification tools. Some risk factors have their impact during the first few days after admittance, others have higher impact on 30 day mortality. Understanding the variance in impact of risk factors is relevant for future composition of risk stratification models.

METHODS: We included patients aged 18 years or older, registered at the Emergency Department at Odense University Hospital from April 1st 2012 to September 30th 2014. We performed multivariate logistic regressions, adjusted for age, gender and comorbidity, to describe the relationship between potential risk factors and measures of short term mortality.

RESULTS: A total of 43,178 were eligible for analysis. Median age was 56 (IQR 36-72) and 48.3% were males. The over-all 30-day-mortality was 4%. One third of deaths occurred within the first 2 days. Higher age, male gender and comorbidity are all associated with immediate, 0-2 day, 3-7 day and 8-30 day mortality. The degree of acuteness at arrival defined by urgency-level, physician-assisted transfer to the Emergency Department and abnormal vital parameters are associated with 0-2 day mortality. High temperature at arrival shows no association in either mortality-group. Missing values are associated with immediate and 0-2 day mortality, but no association with mortality after 7 days.

DISCUSSION: Abnormal vital parameters and degree of acuity at admission were strongly associated with mortality in the first hours and days after admission, where after the association decreased. The effect of other risk factors such as male gender, comorbidity and high age were time stable or even increasing over time..

CONCLUSIONS: The over-all 30-day mortality was 4%. Physiology-related risk factors varied in strength of association throughout different mortality outcome measures.