Variation in Health Care Processes, Quality and Outcomes According to Day and Time of Chest Pain Presentation via Ambulance.

BACKGROUND: Previous studies examining temporal variations in cardiovascular care have largely been limited to assessing weekend and after-hours effects. We aimed to determine whether more complex temporal variation patterns might exist in chest pain care.

METHODS: This was a population-based study of consecutive adult patients attended by emergency medical services (EMS) for non-traumatic chest pain without ST elevation in Victoria, Australia between 1 January 2015 and 30 June 2019. Multivariable models were used to assess whether time of day and week stratified into 168 hourly time periods was associated with care processes and outcomes.

RESULTS: There were 196,365 EMS chest pain attendances; mean age 62.4 years (standard deviation [SD] 18.3) and 51% females. Presentations demonstrated a diurnal pattern, a Monday-Sunday gradient (Monday peak) and a reverse weekend effect (lower rates on weekends). Five temporal patterns were observed for care quality and process measures, including a diurnal pattern (longer emergency department [ED] length of stay), an after-hours pattern (lower angiography or transfer for myocardial infarction, pre-hospital aspirin administration), a weekend effect (shorter ED clinician review, shorter EMS off-load time), an afternoon/evening peak period pattern (longer ED clinician review, longer EMS off-load time) and a Monday-Sunday gradient (ED clinician review, EMS offload time). Risk of 30-day mortality was associated with weekend presentation (Odds ratio [OR] 1.15, p=0.001) and morning presentation (OR 1.17, p<0.001) while risk of 30-day EMS reattendance was associated with peak period (OR 1.16, p<0.001) and weekend presentation (OR 1.07, p<0.001).

CONCLUSIONS: Chest pain care demonstrates complex temporal variation beyond the already established weekend and after-hours effect. Such relationships should be considered during resource allocation and quality improvement programs to improve care across all days and times of the week.