Prognostic Accuracy of SOFA, qSOFA, and SIRS for Mortality Among Emergency Department Patients with Infections

Figures & data

Figure 1 Study flow chart.

Table 1 Baseline Characteristics According to Sepsis Classification

	All Patient N=2045	Sepsis (SOFA ≥2) n=714	No Sepsis (SOFA <2) n=1331	Difference (95% CI) Between Sepsis and No Sepsis
Male sex, n(%)	993(48.6)	417(58.4)	576(43.3)	15.1(10.6–19.6)
Age in years, median, (IQR)	73.2(60.7–82.7)	75.1(66.2–84.1)	72.2(57.1–81.4)	4.4(3.1–5.8)
Chronic disorders
Charlson Comorbidity Index, n(%)
0	630(30.8)	175(24.5)	455(34.2)	9.7(5.6–13.8)
1–2	969(47.4)	350(49.0)	619(46.5)	2.5(−2.0–7.0)
3+	446(21.8)	189(26.5)	257(19.3)	7.2(3.3–11.0)
Congestive heart failure	222(10.9)	110(15.4)	112(8.4)	7.0(4.0–10.0)
Ischemic heart disease^a	225(11.0)	95(13.3)	130(9.8)	3.5(0.5–6.5)
Cerebrovascular disease	285(13.9)	128(17.9)	157(11.8)	6.1(2.8–9.4)
Chronic pulmonary disease	540(26.4)	174(24.4)	366(27.5)	3.1(−0.9–7.1
Diabetes mellitus^b	344(16.8)	152(21.3)	192(14.4)	6.9(3.4–10.5)
Malignancy^c	275(13.5)	100(14.0)	175(13.2)	0.8(−2.3–3.9)
Chronic kidney disease^d	116(5.7)	61(8.5)	55(4.1)	4.4(2.1–6.7)
Chronic mild or severe liver disease	36(1.8)	14(2.0)	22(1.7)	0.3(−0.9–1.5)
Hypertension	672(32.9)	260(36.4)	412(31.0)	5.4(1.1–9.7)
Altered mental status, n(%)	285(13.9)	196(27.5)	89(6.7)	20.8(17.2–24.3)
qSOFA ≥2, n(%)	174(8.5)	140(19.6)	34(2.6)	17.0(14.0–20.0)
SIRS ≥2, n(%)	999(48.9)	425(59.5)	574(43.1)	16.4(11.9–20.9)
SBP ≤ 90 mmHg, (%)	61(3.0)	49(6.9%)	12(0.9)	6.0(4.1–7.9)
Treatment with vasopressor, n(%)	20(1.0)	16(2.2)	4(0.3)	1.9(0.8–3.0)
Laboratory results, median (IQR)
Haemoglobin (mmol/L)	8.1(7.2–8.8)	8.0(7.0–8.9)	8.1(7.3–8.8)	0.1(0–0.2)
C-reactive protein (mg/L)	65(20–137)	78(23–148)	61(18–130)	9.0(3.6–14.5)
White blood cell count (x 10^9/L)	11.1(8.5 −14.9)	11.8 (8.6–16.4)	10.8 (8.4–14.1)	0.9(0.4–1.3)
Creatinine (µmol/L)	82 (63 −113)	114 (76–175)	74 (60–93)	36(31–42)
Platelet count (x 10^9/L)	241 (187–315)	213.5 (148–290.5)	255 (206–323)	46(37–55)
Bilirubin (µmol/L)	9 (6–13)	10 (7–17)	8 (6–11)	2(2–3)
Lactate^e (mmol/L)	1.2 (0.8–1.9)	1.3 (0.9–2.1)	1.0 (0.7–1.7)	0.2(0.1–0.3)
Missing lactate values, n(%)	1273(62.2%)	301(42.2%)	972(73.0%)	30.8(26.5–35.1)
Length of stay, median (IQR)	6.2(2.2–7.9)	6.1(3.7–10.1)	3.9(1.3–6.8)	2.2(1.9–2.7)
Blood cultures, n(%)
Number blood cultures obtained	1101(53.8)	438(61.3)	663(49.8)	11.5(7.0–16.0)
Positive blood cultures	123(6.0)	60(8.4)	63(4.7)	3.7(1.4–6.0)
Foci of infection, n(%)^f
Lungs	1086(53.1)	423(59.2)	663(49.8)	9.4(4.9–13.9)
Urinary	525(25.7)	157(22.0)	368(27.7)	5.7(1.8–9.6)
Abdominal	217(10.6)	71(9.9)	146(11.0)	1.1(−1.7–3.9)
Skin	182(8.9)	48(6.7)	134(10.1)	3.4(1.0–5.8)
Endocarditis	9(0.4)	3(0.4)	6(0.5)	0.1(−0.5–0.7)
Central nervous system	9(0.4)	5(0.7)	4(0.3)	0.4(−0.3–1.1)
Devices/implants	2(0.1)	1(0.1)	1(0.08)	-
Facial/teeth	11(0.5)	2(0.3)	9(0.7)	0.4(−0.2–1.0)
Others	9(0.4)	3(0.4)	6(0.5)	0.1(−0.5–0.7)
Unknown	139(6.8)	60(8.4)	79(5.9)	2.5(0.1–4.9)
2 infection foci	135(6.6)	54(7.6)	81(6.1)	1.5(−0.8–3.8)
3+ infection foci	5(0.2)	3(0.4)	2(0.2)	0.2(−0.3–0.7)

Notes: ^aA history with either myocardial infarction or other symptoms of ischemic heart disease. ^bDiabetes with or without organ damage. ^cMetastatic tumor or tumor without metastasis, leukemia and lymphoma. ^dSevere or mild chronic kidney disease. ^eA total of 772 (37.8%) patients had blood measurements of lactate on admission to the ED. ^fSome patients had more than one site of infection.

Abbreviations: CI, confidence interval; qSOFA, quick sequential organ failure assessment; SBP, systolic blood pressure; SOFA, sequential organ failure assessment; SIRS, systemic inflammatory response syndrome.

Table 2 Incidence, Transfer to ICU and Mortality According to Different Sepsis Criteria

	n	Incidence/Person- Years at Risk (95% CI)	Transfer to ICU % (95% CI)	In-Hospital Mortality % (95% CI)	28-Day Mortality % (95% CI)
All patients	2045		7.5 (6.4–8.7)	3.8 (3.0–4.7)	7.7 (6.6–9.0)
SOFA ≥2	714	721/100,000 (663–768/100,000)	13.5 (11.0–16.2)	7.3 (5.5–9.4)	13.6 (11.2–16.3)
qSOFA ≥2	174	176/100,000 (149–202/100,000)	16.1 (11.0–22.4)	9.2 (5.3–14.5)	17.8 (12.4–24.3)
SIRS ≥ 2	999	1009/100,000 (938–1062/100,000)	10.0 (8.2–12.0)	4.2 (3.0–5.6)	8.3 (6.7–10.2)

Abbreviations: CI, confidence interval; ICU, Intensive care unit.

Table 3 28-Day Mortality According to the SOFA Scores

SOFA Score	N(%)	Mortality, n(%; 95% CI)
0	834(40.8)	33(4.0;2.7–5.5)
1	497(24.3)	28(5.6;3.7–8.0)
2	337(16.5)	30(8.9;6.1–12.5)
3	183(9.0)	22(12.0;7.7–17.6)
4	100(4.9)	13(13.0;7.1–21.2)
5	55(2.7)	20(36.4;23.8–50.4)
6	21(1.0)	4(19.0;5.4–41.9)
7	7(0.3)	3(42.9;9.9–81.6)
8	6(0.3)	3(50.0;11.8–88.2)
9	4(0.2)	2(50.0;11.8–88.2)
10	1(0.05)	0

Abbreviations: CI, confidence interval; SOFA, sequential organ failure assessment.

Table 4 Prognostic Accuracy of SOFA, qSOFA, and SIRS for 28-Day Mortality

	SOFA ≥2	qSOFA ≥2	SIRS ≥2
Sensitivity (95% CI)	61.4 (53.3–69.0)	19.6 (13.7–26.7)	52.5 (44.4–60.5)
Specificity (95% CI)	67.3 (65.1–69.4)	92.4 (91.1–93.6)	51.5 (49.2–53.7)
PPV (95% CI)	13.6 (11.2–16.3)	17.8 (12.4–24.3)	8.3 (6.7–10.2)
NPV (95% CI)	95.4 (94.2–96.5)	93.2 (92.0–94.3)	92.8 (91.1–94.3)
Likelihood ratio (+)	1.9 (1.6–2.2)	2.6 (1.8–3.7)	1.1 (0.93–1.3)
Likelihood ratio (-)	0.6 (0.5–0.7)	0.9 (0.8–0.9)	0.9 (0.8–1.1)
	SOFA	qSOFA	SIRS
AUROC (95% CI)	0.68 (0.64–0.73)	0.63 (0.58–0.67)	0.52 (0.47–0.56)

Abbreviations: AUROC, area under the receiver operating characteristic curve; CI, confidence interval; NPV, negative predictive value; PPV, positive predictive value.

Figure 2 The area under the receiver operating characteristics (AUROC) curves.

Abbreviations: qSOFA, quick sequential organ failure assessment; ROC, receiver operating curve; SIRS, Systemic inflammatory response syndrome; SOFA, sequential organ failure assessment

Table 5 Prognostic Performance of SOFA, qSOFA and SIRS Criteria

Author	Setting Design	Sample Size	Age Years	Follow-Up Period for Mortality	Overall Mortality Rate (%)	Method of Sepsis Score Calculations	Definition of Infection	SOFA≥2 SE SP AUROC	qSOFA≥2 SE SP AUROC	SIRS≥2 SE SP AUROC
Abdullah Present study 2021 Denmark	ED P	2045	73^a	28-day	8	ED arrival. SOFA adjusted for chronic diseases	Patients treated with antibiotics (AB) within 24 hours after ED admission and continued for at least 48 hours	61 67 0.68	20 92 0.63	53 52 0.52
Freund 2017^Citation11 Europe	ED P	879	67^a	IH	8	Worst values during ED stay	Infection diagnosed by the on-duty physician	73 70 0.77	70 79 0.80	93 27 0.65
Seymour 2016^Citation12 Australia	Non-ICU R	66,522	60^b	IH	3	Worst values during ED stay	Combination of AB treatment and cultures obtained	NR NR 0.79	NR NR 0.81	NR NR 0.76
Raith 2017^Citation21 New Zealand	ICU R	184,875	63^b	IH	19	On ICU admission. SOFA calculation was adjusted for chronic diseases	Infection-related ICU-admission diagnosed according to Australian and New Zealand Intensive Care Society guidelines^Citation31	NR NR 0.75	NR NR 0.61	NR NR 0.59
April 2017^Citation22 USA	ICU R	214	68^b	IH	18	Worst values during ED stay	Administration of AB during ED stay and cultures obtained within 24h	NR NR 0.75	89.7 27.4 0.66	97.4 2.3 0.65
Donnelly 2017^Citation23 USA	Non-ICU R	2593	69^c	IH	6	Worst values during the first 28 hours of admission	The criteria of Angus et al^Citation32	NR NR 0.77	NR NR 0.76	NR NR 0.72
Gaini 2018^Citation24 Denmark	HW R	323	66^a	IH	6	Not specified	Suspicion of infection by the on-duty physician	100 44 0.83	38 89 0.67	81 28 0.61
Blanco 2018^Citation19 Tanzania	ED R	519	30^a	28-day	6	Not specified	Infections criteria derived from World Health Organization, Infectious Diseases Society of America guidelines and European Society of Clinical Microbiology and Infectious Diseases guidelines^Citation33	72 73 0.79	59 88 0.80	91 19 0.61
Kovach 2019^Citation13 USA	ICU + Non-ICU R	10,981	52^a	IH	7	Not specified	Combination of intravenous AB treatment and cultures obtained.	NR NR 0.90	NR NR 0.84	NR NR 0.79
Poutsiaka 2019^Citation14 USA	ICU + ED P	176	61^a	30-day	15	Not specified	Two physicians from the department of infectious diseases determined infection	NR NR 0.84	NR NR 0.69	NR NR 0.54
Machado 2020^Citation9 Brazil	Non-ICU P	5460	64^a	IH	14	Worst values from arrival until sepsis was suspected. For HW patients 24 hours prior to suspicion of sepsis.	Treatment with AB after blood cultures obtained and diagnosis determined by on-duty physician	88 60 0.83	54 84 0.75	76 25 0.53
Lopez 2020^Citation25 Spain	Selective cohort ED P	870	70^a	2-day	8	Arrival variables or worst values during stay.	Not specified	88 81 0.91	85 69 0.81	NR NR NR
Falsetti 2020^Citation34 Italy	ICU + Non-ICU R	390	80^b	IH	37	Not specified	Not specified	NR NR 0.69	NR NR 0.68	NR NR NR
Umemura 2017^Citation35 Japan	ICU R	387	74^a	IH	28	Not specified	Not specified	NR NR 0.70	91 19 0.62	NR NR 0.53

Notes: ^aMedian; ^bMean; ^cMean age for patients fulfilling SOFA ≥2.

Abbreviations: AB, antibiotic; AUROC, area under the receiver operating characteristic curve; CI, confidence interval; ED, emergency department; ICU, intensive care unit; IH, in-hospital; HW, hospital wards; NR, not reported; P, prospective; R, retrospective; SE, sensitive; SP, specificity; SIRS, systemic inflammatory response syndrome, SOFA, sequential organ failure assessment; qSOFA, quick sequential organ failure assessment.

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