A literature review of severity scores for adults with influenza or community-acquired pneumonia – implications for influenza vaccines and therapeutics

Figures & data

Table 1. Characteristics of studies included in the review of severity scores among patients with community acquired pneumonia or influenza

First author	Publication year	Scale(s)	Disease	Outcome(s)	Country	Study design	Setting	Number	Mean age	% Male
Adeniji^Citation13	2011	SOFA, STSS	H1N1	mortality, ICU admission, mechanical ventilation	UK	Retrospective	Critical care/ICU	62	41	56.5
Agapakis^Citation14	2010	CURB-65	CAP	hospitalization	Greece	Prospective	Internal Medicine	77	65.9	62.3
Ahn^Citation15	2018	CURB-65, PSI, A-DROP	CAP	mortality (28 days)	South Korea	Retrospective	Emergency or Outpatient	1031	69.2	66.7
Ahnert^Citation16	2019	CRB-65, CURB-65, Halm, IDSA/ATSmc, PSI, qSOFA, SCAP, SIRS, SMART-COP, SOFA	CAP	mortality, ICU admission	Germany, Austria	Prospective	Admitted, Emergency/Acute Care, Critical care/ICU	1532	59	59
Alan^Citation17	2015	CURB-65, PSI	CAP	mortality (6 years)	Switzerland	Prospective	Emergency/Acute Care	925	73	58.8
Aliberti^Citation18	2011	CURB-65	CAP	hospitalization	Italy	Retrospective	Emergency/Acute Care	580	68	56
Andersen^Citation19	2017	CURB-65	CAP	mortality (30 days)	Denmark	Retrospective	Emergency/Acute Care	814	72	47
Andrijevic^Citation20	2014	CURB-65, PSI, MEWS	CAP	mortality (30 days)	Serbia	Prospective	Pulmonary/Respiratory	101	63.7	75.2
Angus^Citation21	2002	PSI, ATS, BTS	CAP	mortality, disease complications, ICU admission, mechanical ventilation	USA and Canada	Prospective	Admitted	1339	N/A	N/A
Arminanzas^Citation22	2013	CURB-65, Charleson Index	CAP	mortality (30 days)	Spain	Prospective	Internal Medicine	539	78	51
Asai^Citation23	2019	A-DROP, CURB-65,I-ROAD, PSI, qSOFA, and SOFA	CAP, HCAP	mortality (30 days), in-hospital mortality	Japan	Retrospective	Admitted	406	79	63
Bello^Citation24	2012	CURB-65, PSI	CAP	mortality	Spain	Prospective	Emergency/Acute Care	228	73	61
Bloos^Citation25	2011	APACHE II, SOFA	CAP, VAP, HAP	mortality (28 days)	Canada, USA, Europe	Prospective	Critical care/ICU	175	62	61.7
Buising^Citation26	2007	CURB-65, PSI, BTS, CURB, CORB	CAP	mortality, ICU admission, IRVS, mechanical ventilation	Australia	Prospective	Emergency/Acute Care	392	74	59.7
Capelastegui^Citation27	2006	CURB-65, CRB-65	CAP	mortality (30 days)	Spain	Prospective	Emergency/Acute Care	1776	61.8	63.3
Chalmers^Citation28	2008	CURB-65, PSI, SMART-COP, CRB-65	CAP	mortality (30 days), IRVS, mechanical ventilation	UK	Prospective	Emergency/Acute Care	335	36	N/A
Chen^Citation29	2010	CURB-65, PSI	CAP	mortality (30 days)	Taiwan	Prospective	Emergency/Acute Care	987	68	61.9
Chen^Citation30	2020	CURB-65, PSI	H1N1, H3N2	mortality (30 days), ICU admission, mechanical ventilation	China	Retrospective	Admitted	693	N/A	66.5
Chiang^Citation31	2013	APACHE II, CURB-65, PSI	CAP	disease severity	Taiwan	Prospective	Emergency or Outpatient	60	59.7	60
Cho^Citation32	2015	CURB-65, PSI	CAP	mortality	South Korea	Prospective	Emergency/Acute Care	56	64.4	69.6
Choi^Citation33	2011	CURB-65, PSI	H1N1 Associated Pneumonia	mortality	South Korea	Retrospective	Admitted	269	48	53.2
Chou^Citation34	2016	CURB-65, PSI	CAP	mortality, disease severity	Taiwan	Prospective	Admitted	279	65.4	58.4
Christ-Crain^Citation35	2006	PSI	CAP	mortality	Switzerland	Prospective	Emergency/Acute Care	302	69.6	61.9
Christ-Crain^Citation36	2008	PSI	CAP	mortality, treatment failure	Switzerland	Prospective	Emergency/Acute Care	302	69	61.9
Courtais^Citation37	2013	PSI	CAP	mortality (30 days)	France	Prospective	Emergency/Acute Care	109	71	65.1
Davis^Citation38	2010	SMART-COP	pneumonia	mortality (30 days), IRVS	Australia	Prospective	Admitted	184	50.1	56
Dwyer^Citation39	2014	CURB-65	CAP	mortality (30 days)	Sweden	Retrospective	Admitted or Outpatient	1172	64	49.6
Ehsanpoor^Citation40	2019	SMART-COP	CAP	mortality (30 days), ICU admission, length of stay, IRVS	Iran	Prospective	Emergency/Acute Care	143	68.1	52.4
Espana^Citation41	2006	CURB-65, PSI, SCAP	CAP	mortality (30 days)	Spain	Prospective	Emergency/Acute Care	1776	64.7	63.3
Espana^Citation42	2012	CURB-65	CAP	disease severity	Spain	Prospective	Emergency or Family Physician	344	53.5	57.3
Espana^Citation43	2015	CURB-65, PSI, SCAP	CAP	mortality (30 days), disease complications	Spain	Prospective	Emergency/Acute Care	491	N/A	63.1
Ewig	1998	ATS, BTS	CAP	mortality, ICU admission	Spain	Prospective	Admitted	696	67.8	66
Flanders^Citation44	1999	PSI	CAP	mortality	USA	Retrospective	Admitted	1024	67	43
Fukuyama^Citation45	2011	CURB-65, PSI, SMART-COP, Espana rule, IDSA/ATS rule	CAP	mortality, ICU admission	Japan	Prospective	Admitted	505	76	67.1
Gearhart^Citation46	2019	IDSA/ATS	CAP	ICU admission	USA	Retrospective	Admitted	8284	68	46
Golcuk^Citation47	2015	CURB-65	CAP	mortality (28 days)	Turkey	Prospective	Emergency/Acute Care	174	66.7	66.1
Gordo-Remartinez^Citation48	2015	PSI	CAP	mortality (30 days, 90 days), ICU admission, hospital readmission	Spain	Prospective	Emergency/Acute Care	226	75.6	55.3
Grudzinska^Citation49	2019	CURB-65, Lac-CURB-65, NEWS, qSOFA	CAP, HCAP	mortality (30 days, 90 days, 1 year), in-hospital mortality, ICU admission, length of stay	UK	Retrospective	Admitted	1545	76	50.8
Gunaydin^Citation50	2019	CURB-65, PSI	CAP	mortality	Turkey	Prospective	Internal Medicine	63	72.1	57.1
Guo^Citation51	2012	PSI, IDSA/ATS	CAP	mortality	China	Retrospective	Admitted	1230	47.5	49.3
Gwak^Citation52	2015	PSI	CAP	mortality	South Korea	Retrospective	Emergency/Acute Care	397	71.4	57.7
Hamaguchi^Citation53	2018	CURB-65, PSI	CAP, HCAP	mortality	Japan	Prospective	Outpatient	1772	77	58.7
Huaman^Citation54	2011	CURB-65, SMART-COP, SMRT-CO	CAP	ICU admission	USA	Retrospective	Admitted	115	61.6	48.7
Huang^Citation55	2008	CURB-65, PSI	CAP	mortality (30 days)	USA	Prospective	Emergency/Acute Care	1651	65	52
Huang^Citation56	2009	CURB-65, PSI	CAP	mortality (30 days)	USA	Prospective	Emergency/Acute Care	1653	65	52
Ito^Citation57	2017	CURB-65, PSI, IDSA/ATS, A-CROP	CAP	mortality (30 days), ICU admission	Japan	Retrospective	Admitted	1834	73.5	69.8
Jain^Citation58	2012	N/A	Pandemic H1N1-associated pneumonia	mortality, ICU admission	USA	Retrospective	Admitted	451	29	48
Jeong^Citation59	2013	PSI	CAP, HCAP	mortality	South Korea	Retrospective	Emergency/Acute Care	247	68	67.4
Jo^Citation60	2016	CURB-65, NEWS, PSI	CAP	mortality	South Korea	Retrospective	Admitted	553	70.1	62.6
Justel^Citation61	2013	APACHE II	Pandemic influenza	mortality	Spain	Prospective	Critical care/ICU	40	N/A	70
Kasamatsu^Citation62	2012	CURB-65, PSI, A-DROP	CAP	mortality (30 days)	Japan	Prospective	Internal Medicine	170	67.9	57.6
Katsoulis^Citation63	2005	PSI	CAP	disease severity	Greece	Prospective	Pulmonary/Respiratory	40	N/A	75
Kim^Citation64	2016	CURB-65, PSI	CAP	mortality (30 days)	South Korea	Prospective	Emergency/Acute Care	386	75	60.2
Kim^Citation65	2017	APACHE II, CURB-65, PSI, qSOFA, SOFA	CAP	mortality (28 days)	South Korea	Retrospective	Emergency/Acute Care	125	N/A	62.4
Ko^Citation66	2014	APACHE II, CURB-65, PSI	CAP	mortality	Taiwan	Prospective	Admitted	121	59	60
Kolditz^Citation67	2010	PSI	CAP	mortality, ICU admission, clinical instability after 72 h	Germany	Prospective	Emergency or Outpatient	59	72	52
Lee^Citation68	2011	PSI	CAP	mortality (28 days)	South Korea	Prospective	Emergency/Acute Care	424	70.4	35
Lee^Citation69	2016	PSI	CAP	mortality (30 days)	South Korea	Prospective	Emergency/Acute Care	470	71.5	68.7
Leroy^Citation70	1996	SAPS II, Glasgow score, pneumonia specific prognostic index	CAP	mortality	France	Prospective & Retrospective	Critical care/ICU	335	63	63
Li^Citation71	2015	CURB-65, CUR-65	CAP	mortality	China	Retrospective	Pulmonary/Respiratory	1230	47.5	49.3
Li^Citation72	2015	IDSA/ATS	CAP	mortality	China	Retrospective	Pulmonary/Respiratory	1230	47.5	49.3
Liapikou^Citation73	2009	IDSA/ATS guidelines	CAP	mortality (7 days, 30 days), ICU admission	Spain	Prospective	Emergency/Acute Care	2102	N/A	61.4
Lim	2000	BTSr, mBTSr	CAP	mortality	UK	Retrospective	Admitted	122	76	56
Lim^Citation74	2003	CURB-65, PSI, CURB, CRB-65	CAP	mortality (30 days)	UK, New Zealand, Netherlands	Prospective	Admitted	1068	64.1	51
Liu^Citation75	2014	CURB-65	SCAP/CAP	mortality (28 days), Acute Respiratory Distress Syndrome (ARDS), disseminated intravascular coagulation (DIC)	China	Prospective	Emergency/Acute Care	573	N/A	62.1
Liu^Citation76	2016	CURB-65, PSI, SMART-COP, expanded CURB-65, A-DROP	CAP	mortality (30 days), length of stay	China	Retrospective	Admitted	1640	64	59.6
Loh	2004	BTS	CAP	mortality, length of stay	Malaysia	Prospective	Admitted	108	55	58
Luo^Citation77	2018	CURB-65, PSI	CAP	mortality, hospital discharge, disease severity, in-hospital mortality	China	Prospective	Admitted	188	68	64.4
Mahendra^Citation78	2018	CURB-65	CAP	ICU admission	India	Prospective	Pulmonary/Respiratory	100	54	66
Mamani^Citation79	2017	CURB-65	CAP	mortality (30 days), ICU admission, length of stay	Iran	Prospective	Admitted	149	N/A	69.9
Masia^Citation80	2005	PSI, PORT PSI	CAP	mortality	Spain	Prospective	Admitted	240	59	62.5
Meier^Citation81	2017	CURB-65, PSI, qSOFA	CAP	mortality (30 days, 6 years), ICU admission	Switzerland	Retrospective	Emergency/Acute Care	268	N/A	60.1
Mendez^Citation82	2019	CURB-65, SOFA	L-CAP	mortality (30 days), length of stay, treatment failure	Spain	Prospective	Admitted	217	N/A	62.2
Menendez^Citation83	2009	CURB-65, PSI, CRB65	CAP	mortality (30 days)	Spain	Prospective	Admitted	453	67.3	62.2
Miller^Citation84	2012	CURB-65, PSI, SIRS	H1N1	mortality, ICU admission	USA	Prospective	Admitted	43	36.4	19
Miyazaki^Citation85	2018	PSI, A-DROP	CAP	mortality (30 days)	Japan	Prospective	Pulmonary/Respiratory	534	76.2	63.3
Muller^Citation86	2006	PSI	CAP	mortality	Switzerland	Prospective	Emergency/Acute Care	545	67.1	62.6
Muller^Citation87	2007	PSI	LRTI, CAP	mortality, disease cure	Switzerland	Retrospective	Emergency/Acute Care	545	67.1	62.6
Murcia^Citation88	2010	PSI, Barthel index	CAP	mortality (30 days)	Spain	Prospective	Emergency/Acute Care	518	60.7	65.8
Naderi^Citation89	2015	CURB-65, PSI, SMART-COP, CRB-65, IDSA/ATS 2007	CAP	mortality, IRVS	Iran	Prospective	Admitted	120	50.4	14.3
Nastasijevic Borovac^Citation90	2014	PSI	CAP	mortality	Serbia	Prospective	Admitted	129	N/A	N/A
Nicolini^Citation91	2012	Opravil XRC	H1N1-associated pneumonia	severity of pulmonary infiltrates	Italy	Retrospective	Critical care/ICU	28	31.7	53.6
Nowak^Citation92	2012	CURB-65, PSI	CAP	mortality (30 days, long-term)	Switzerland	Prospective	Emergency/Acute Care	341	75	61
Oh^Citation93	2011	APACHE II	H1N1	disease severity, length of stay, antiviral regimens	South Korea	Prospective	Admitted	709	50	39.5
Papadimitriou-Olivgeris^Citation94	2020	CURB-65, PSI, qSOFA, SIRS, SOFA	Influenza A and B	mortality (30 days), disease complications, disease severity, hospitalization, ICU admission, length of stay, mechanical ventilation	Switzerland	Retrospective	Admitted	441	N/A	46
Parsonage^Citation95	2009	CURB-65	CAP	mortality (30 days), ICU admission, in-hospital mortality	United Kingdoms	Prospective	Emergency/Acute Care	428	N/A	47
Pereira	2012	CURB-65, PSI, PIRO-CAP	H1N1-associated CAP	mortality	31 different countries	Prospective	Admitted	265	42	54
Phua^Citation96	2009	CURB-65, PSI, IDSA/ATS minor criteria	CAP	mortality, ICU admission	Singapore	Retrospective	Admitted	1242	65.7	61.3
Querol-Ribelles^Citation97	2004	APACHE II, PSI	CAP	mortality	Spain	Prospective	Emergency/Acute Care	302	73	74.8
Remmelts^Citation98	2012	CURB-65, PSI	CAP	mortality (30 days), ICU admission	Netherlands	Prospective	Emergency/Acute Care	272	63.5	56
Renaud^Citation99	2012	REA-ICU	CAP	mortality (30 days), ICU admission, IRVS, length of stay, mechanical ventilation	Switzerland	Retrospective	Emergency/Acute Care	877	73	58.8
Richards^Citation100	2011	APACHE II, CURB-65, PSI	CAP	mortality (28 days), in-hospital mortality	11 different countries	Retrospective	Admitted	278	64	N/A
Robins-Browne^Citation101	2012	PSI, SMART-COP, SMARTACOP, CORB	CAP	mortality (30 days), IRVS	Australia	Prospective	Emergency/Acute Care	367	50	52
Ronan^Citation102	2010	CURB-65, CRB-65	CAP	mortality (30 days)	Scotland	Retrospective	Emergency/Acute Care	428	N/A	47
Salluh^Citation103	2011	APACHE II, CURB-65, SOFA	CAP	mortality, in-hospital mortality	Brazil	Prospective	Critical care/ICU	90	73.5	44.4
Schuetz^Citation104	2008	CURB-65, PSI	CAP	mortality, ICU admission	Switzerland	Retrospective	Emergency/Acute Care	281	74	62
Schuetz^Citation105	2008	CURB-65, PSI	CAP	mortality, ICU admission, outpatient management	Switzerland	Retrospective	Emergency/Acute Care	373	73	60.1
Schuetz^Citation106	2010	CURB-65, PSI	LRTI, CAP	mortality, disease complications, ICU admission	Switzerland	Retrospective	Emergency/Acute Care	925	72	58.8
Shindo^Citation107	2008	CURB-65, A-DROP	CAP	mortality (30 days)	Japan	Retrospective	Admitted	329	75	59.9
Siljan^Citation108	2018	CURB-65	CAP	mortality (30 days), ICU admission	Norway	Prospective	Internal Medicine	247	64	51.8
Song^Citation109	2019	qSOFA	CAP	mortality, in-hospital mortality	South Korea	Retrospective	Emergency/Acute Care	443	66.5	57.1
Spoorenberg^Citation110	2017	CURB-65, PSI	CAP	mortality (30 days, long-term), ICU admission, in-hospital mortality	Netherlands	Retrospective	Admitted	289	64	55.7
Talmor^Citation111	2007	Triage rule	H5N1	mortality, in-hospital mortality	USA	Retrospective	Emergency/Acute Care	5133	N/A	48.2
Valencia^Citation112	2007	CURB-65, PSI, ATS, CURB	CAP	mortality, ICU admission	Spain	Prospective	Admitted	457	79	70
Vecchiarino^Citation113	2004	PSI	CAP	mortality (30 days), hospital discharge, length of stay, hospital readmission	USA	Prospective	Admitted	213	72.5	47.4
Vicco^Citation114	2015	CURB-65, SCAP	CAP	mortality	Argentina	Prospective	Admitted	272	52	48.2
Wang^Citation115	2013	APACHE II, CURB-65, PSI	CAP	levels of YKL-40 concentration	Taiwan	Prospective	Admitted	121	59.5	60.3
Wang^Citation116	2017	APACHE II, CURB-65, PSI, SOFA, CLCGH	SCAP	mortality (28 days), length of stay, mechanical ventilation, duration of ICU stay	China	Retrospective	Critical care/ICU	37348	70.9	51.5
Wu^Citation117	2009	APACHE II	CAP	mortality (28 days)	Taiwan	Prospective	Emergency/Acute Care	63	70	63.5
Yang^Citation118	2014	PSI	H1N1/H3N2	disease severity	China	Prospective	Admitted	88	52	54.5
Yeon Lee^Citation119	2016	CURB-65, PSI	CAP	mortality (30 days)	South Korea	Retrospective	Pulmonary/Respiratory	797	N/A	64.1
Yin^Citation120	2014	CURB-65, PSI	CAP	mortality (30 days)	China	Prospective	Emergency/Acute Care	573	74	62.1
Zhang^Citation121	2018	CURB-65, PSI	CAP	mortality (30 days)	Singapore	Retrospective	Emergency/Acute Care	1902	73	55.5
Zhou^Citation122	2012	genetic variations	H1N1	disease severity	Hong Kong	Prospective	Admitted or Outpatient	425	N/A	48.9
Zhou^Citation123	2018	CURB-65, PSI, qSOFA, SOFA	CAP	mortality (28 days)	China	Retrospective	Emergency/Acute Care	226	65	84.1
Zhu^Citation124	2018	APACHE II	H1N1/H7N9 Influenza	N/A	China	Prospective	Admitted	93	N/A	54.8
Zimmerman^Citation125	2010	CRP levels	H1N1 Influenza A virus	ICU admission, mechanical ventilation	Israel	Retrospective	Emergency/Acute Care	191	43	50
de Jager^Citation126	2012	CURB-65	CAP	mortality, ICU admission	Netherlands	Prospective	Emergency/Acute Care	395	63	61

N/A = Overall mean age and/or percent male of study participants was not available in the study report.

Figure 1. Study selection flow diagram.

Table 2. Summary of included study characteristics

Characteristics	N (%)
Total studies	118
Study Origin
Asia	43 (36.4)
Europe	50 (42.4)
Global/multi-country	5 (4.2)
Middle East	6 (5.1)
North America^a	9 (7.6)
Oceania	3 (2.5)
South America	2 (1.7)
Publication Year
1996–2000	4 (3.4)
2001–2005	7 (5.9)
2006–2010	28 (23.7)
2011–2015	47 (39.8)
2016–2020	32 (27.1)
Study Design
Prospective	74 (62.7)
Retrospective	43 (36.4)
Both	1 (0.9)
Disease
Pneumonia^b	103 (87.3)
Influenza^c	11 (9.3)
Both^d	4 (3.4)
Scores^e
A-DROP	7 (5.9)
APACHE II	13 (11.0)
CURB-65	73 (61.9)
IDSA/ATS	9 (7.6)
NEWS	2 (1.7)
PSI	74 (62.7)
qSOFA	8 (6.8)
SAPS II	1 (0.9)
SMART-COP	9 (7.6)
SOFA	10 (8.5)
Other^f	38 (32.2)
Outcomes^e
Discharge	2 (1.7)
Disease complications/severity	13 (11.0)
Hospitalization	3 (2.5)
ICU admission	33 (28.0)
Intensive respiratory or vasopressor support (IRVS)	7 (5.9)
Length of hospital/ICU stay	11 (9.3)
Mechanical ventilation	9 (7.6)
Mortality	103 (87.3)
Readmission	2 (1.7)
Treatment failure	2 (1.7)
Other	8 (6.8)
	Median (IQR)
Patients Evaluated	370 (175–709)
% Male	59.3 (52–62.6)
Mean age	67 (59.7–72.1)

^aAll studies from United States of America.

^bIncludes community-acquired pneumonia (CAP), hospital-acquired pneumonia (HAP), healthcare-associated pneumonia (HCAP), lymphopenic community-acquired pneumonia (L-CAP), lower respiratory tract infections (LRTIs), severe community-acquired pneumonia (SCAP), and ventilator-associated pneumonia (VAP).

^cIncludes H1N1, H3N2, H5N1, and H7N9.

^dAll studies on H1N1-associated pneumonia.

^eNot mutually exclusive.

^fOthers include modified or earlier versions of scores described.

Figure 2. Predictors of poor outcomes by severity scores.

Legend: BP = blood pressure, RR = respiratory rate, HR = heart rate/pulse, O2 = oxygen saturation, BUN = blood urea nitrogen, WBC = white blood cell^aAge adjustments for RR and O2, ^bSystolic, ^cMean arterial pressure (mmHg), ^dHypotension, ^eVentilated or non-ventilated, ^fRespiratory rate or complaining of breathlessness, ^gAbnormal ECG (does not include bradycardia or tachycardia), ^hTachycardia, ⁱOxyhemoglobin saturation measured by pulse oximetry or partial pressure of oxygen in arterial blood (PaO2), ^jAaDO2 or PaO2, ^kPaO2/FiO2 ratio, ventilated or CPAP, ^lPartial pressure of oxygen, ^mPaO2, SaO2, or PaO2/FiO2, ⁿhypothermia, ^oBUN or dehydration, ^pThrombocytopenia, ^qleukopeniac, ^rConfusion, ^sGlasgow Coma Score, ^tLevel of consciousness or new confusion using Alert Voice Pain Unresponsive (AVPU) scale, ^uComa (responds only to pain or unresponsive) and altered mental status (not intoxicated), ^vConfusion (new onset), ^wFactored into respiratory rate, ^xMechanical ventilation or CPAP, ^yUnscheduled surgical, scheduled surgical, or medical, ^zseptic shock with the need for vasopressors, ^aaCerebrovascular disease, congestive heart failure, hepatic disease, renal disease, neoplastic disease, ^abHIV, hematologic malignancy, metastatic cancer, ^acDisability: stroke (new presentation), unable to stand unaided, prior illness (some part of daytime in bed), diabetes (type 1 or 2), ^adMultilobar chest x-ray infiltrates, ^aePleural effusion.

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