Table 2.

Predictive characteristics of frequent ED use

Predictive factors	Details	References
Demographic
Male		[27, 30, 37]
Female		[11]
Age	75 years and older	[11, 37]
	Between 30 and 59 years old	[30]
	Lower age	[41]
Location	Attendance at a rural ED	[11]
	Urban area (Philadelphia County)	[33]
	Core area patients (Winnipeg Health Region)	[27]
Distance to ED	Less than 10 km	[6]
	More than 2 km	[37]
Socioeconomic
Education	No high school diploma	[40]
	High school education (or less)	[8, 33]
Family status	Single parents	[8, 40]
	Single	[8]
	Divorced	[8]
	Being under guardianship	[6]
	Number of children living in the house	[33]
Housing status	Homeless	[30, 42]
Income	Living in lowest income areas	[27]
	Being unemployed or dependant of government welfare	[6]
	Receiving government pension	[42]
	Family income below the poverty threshold	[4]
	Low socioeconomic status	[9]
	Low income groups	[40]
	Income of less than 10 000$	[8]
Insurance	Being uninsured	[3, 4, 6]
	Medicaid	[3, 4]
	Medicare coverage	[4, 23]
	Publicly insured	[3, 40]
	Medical Assistance	[33]
	Medi-Cal sponsored	[30]
Current healthcare use	Multiple visits to a specialist physician	[9, 27, 41]
	Multiple visits to a primary care provider	[5, 8, 27, 40]
	Calling a health helpline	[27]
	Being hospitalized	[3, 5, 6, 8, 10, 27, 41]
	Outpatient visits	[4, 5, 10]
	Visiting a clinic	[4, 6, 33]
	History of past emergency department use	[3, 27, 39]
	Identifying an ED or hospital clinic as primary care site	[8]
	Prescription medication use	[3, 9, 33]
Access to primary healthcare services	Having a primary care provider	[8, 11]
	ED as primary source of care	[4, 8]
	Having another regular source of care	[10]
Medical
Mental illness	Substance abuse problems	[10, 27, 30]
	Mental disorder	[4, 6, 8, 9, 42]
Physical disease
Chronic condition		[10, 27]
Exacerbation of chronic conditions	Sickle cell anemia, renal failure, chronic obstructive pulmonary disease	[30]
Fair/poor physical health		[4, 40]
Other diseases	Pulmonary disease	[3, 8, 10, 37]
	Cardiovascular disease	[10]
	Gastrointestinal disease	[10]
	Cancer	[10]
Medical scores	Severe rating on MIDAS	[9, 41]
	Lower role physical domain	[41]
	Higher DRG severity score	[23]