Patient characteristics
Age	Grouped into 18-44; 45-64; 65-69; 70-74; 75-79; 80-84; and 85+ years of age
Sex	Male or female
Ethnicity	Based on the following groupings:
	White; Asian; Black; other; and not known.
Comorbidities	Based on any relevant International Classification of Diseases–Tenth Revision code appearing in the discharge diagnosis codes (25 possible codes)
	Myocardial infarction; congestive heart failure; peripheral vascular disease; stroke; dementia; pulmonary; rheumatic; peptic ulcer disease; liver (mild); liver (severe); diabetes; diabetes (complex); paralysis; renal; metastatic cancer; human immunodeficiency virus.
Deprivation quintile	Measured as the deprivation score of the patient’s primary care practice, obtained by matching patients to their registered practice. If patients did not have a registered primary care practice or the practice was not included in the Public Health England practice profiles a “missing” categorization was allocated. There are therefore 6 deprivation categories, with Quintile 1 being the least deprived.
	Admission characteristics
Admitting hospital	A has an ED department
	B no ED department
	C has an ED department
Season of admission	Spring: March, April, May
	Summer: June, July, August
	Autumn: September, October, November
	Winter: December, January, February
	Patient severity
NEWS score	Categorized into: zero, low, medium, high, and none recorded
	NEWS = 0: zero
	1 ≤ NEWS < 5: low
	5 ≤ NEWS < 7: medium
	7 ≥ NEWS: high
	A NEWS score is available for 19 599 (90%) of the patients.
Alert	Suspected sepsis
	Suspected severe sepsis