Table 3.

Incidence of community-onset sepsis: cohort studies

Study ID country	Cohort and study characteristics	Study design and duration of follow-up	Type of sepsis	Incidence – overall (total cohort)			Methodological quality (high, acceptable, low)
				N of cases per 100,000 population per year [95% CI]	CIP % per hospitalisation or ED visit per year [95% CI]	IDR (N of cases per 100,000 p-y) [95% CI]
Esteban 2007 [46] Spain	Geographic scope	Prospective cohort study	Non-severe	367 [352, 384]	13.28% [12.76, 13.81]	NR	Acceptable quality
	City/municipal		Severe	104 [96, 113]	3.76% [3.47, 4.06]	NR
		FU: 4 months
	Setting		Septic shock	31 [27, 36]	1.11% [0.95, 1.28]	NR
	ICU, hospital ward
	Cohort denominator
	N (population)=573,149
	N (hospitalisations)=15,852
Ginde 2013 [47] The USA	Geographic scope	Retrospective cohort study	Severe	NR	0.40% [0.39, 0.41]	NR	Low quality
	Nationwide
	Setting	FU: 5 years
	ED
	Cohort denominator
	N (population)=NR
	N (all ED visits)=87,500,000
Harrison 2006 [11] The UK	Geographic scope	Retrospective cohort study	Severe	66 [NR]μ	27.87% [27.52, 28.24]	NR	Acceptable quality
	Nationwide
	Setting	FU: 2 years
	ICU, combination of ICU with HDU
	Cohort denominator
	N (population)=NR
	N (hospitalisations)=59,527
Henriksen 2015a [42] Denmark	Geographic scope	Prospective cohort study	All	727 [693, 762]	NR	731 [697, 767]	Acceptable quality
	City/municipal		Non-severe	264 [243, 285]	NR	265 [245, 287]
	Setting	FU: 1 year	Severe	455 [428, 482]	NR	457 [430, 485]
	ED, ICU		Septic shock	9 [6, 13]	NR	9 [6, 14]
	Cohort denominator
	N (population )=235,598
	N (hospitalisations)=8,358
Husak 2010 [48] Canada	Geographic scope	Retrospective cohort study	All	103 [NR]μ	NR	NR	Low quality
	Nationwide		Non-severe	64 [NR]μ	NR	NR
	Setting	FU: 5 years	Severe	40 [NR]μ	NR	NR
	ED, ICU, hospital ward
	Cohort denominator
	N (population or hospitalisations)=NR
Nygard 2014 [49] Norway	Geographic scope	Prospective cohort study	Severe	50 [NR]μ	0.22% [NR]μ	NR	Low quality
	City/municipal
	Setting	FU: 1 year
	ED, ICU, HDU, combination of ICU with HDU
	Cohort denominator
	N (population or hospitalisations)=NR
Page 2015 [50] The USA	Geographic scope	Retrospective cohort study	Severe	NR	CA-SS	NR	Low quality
	Nationwide				5.75% [5.72, 5.77]
	Setting	FU: 1 year			HCA-SS
	NR				2.37% [2.35, 2.38]
	Cohort denominator
	N (population)=NR
	N (hospitalisations)=3,355,753
Wang 2012 [36] REGARDS-sepsis cohort study 2012-2015β The USA	Geographic scope	Prospective cohort study	Non-severe	514 [489, 539]	NA	800 [760, 840]	Acceptable quality
	Nationwide
	Setting	FU: 9-10 years
	Hospital ward, ED
	Cohort denominator
	N (population)=30,239
	N (hospitalisations)=NR
Seymour 2012 [51]The USA	Geographic scope	Retrospective cohort study	Severe	NR	Entire 10-year cohort	NR	Low quality
	Regional (within-State)				3.25% [3.20, 3.31]
	Setting	FU: 10 years			One-year cohort
	Pre-hospital emergency medical services				4.93% [4.73, 5.13]
	Cohort denominator
	N (population)= NR
	N (emergency encounters)=407,176
Wang 2007 [52] The USA	Geographic scope	Retrospective cohort study	Severe	NR	0.69% [0.61, 0.77]	NR	Low quality
	Nationwide
	Setting	FU: 4 years
	ED
	Cohort denominator
	N (population)=NR
	N (ED visits)=82,883,000

CIP cumulative incidence proportion, IDR incidence density rate, HR hazard rate, n/N number, p-y person-years, 95% CI 95 percent confidence interval; REGARDS Reasons for Geographic And Racial Differences in Stroke, FU follow-up, ED emergency department, NA not applicable; NR not reported, ICU intensive care unit, HDU high dependence unit, CA-SS community-acquired severe sepsis, HCA-SS healthcare-acquired severe sepsis

^μ 95 % CIs cannot be calculated, due to the lack of denominator reported

^β REGARDS-sepsis cohort study publications [32–38, 40, 41]