Table 1

Characteristics of included studies that directly investigated the influence of comorbidity on OHCA outcomes

Study IDCountryStudy designCasesEnrolment
Reported outcomeComorbiditySource of comorbidity dataInclusion criteriaAge
Andrew et al 20179 AustraliaRetrospective cohort15 953Jan 2007–Dec 2014Survival to hospital dischargeCCI=0,1,2,3,≥4, hypertension, diabetes, myocardial infarction, cerebrovascular disease, congestive heart failure, chronic obstructive disease, cancer, metastatic cancer, dementia, peripheral vascular disease, peptic ulcer, HIV/AIDS, skin ulcers, connective tissue disease.Ambulance patient care records.All non-traumatic arrests with an attempted resuscitation.≥16
Beesems e t al 201510 NetherlandsProspective cohort851Jan 2009–Dec 2011Survival with good neurological outcome (CPC 1–2)CCI ≥4.Patients general practitioner.All non-traumatic arrest patients without DNR orders and in whom resuscitation was started.≥70
Blom et al 20135 NetherlandsProspective cohort11722005–200830-day survival
Neurological outcome at hospital discharge
Cardiovascular disease, obstructive pulmonary disease.Presence of at least two condition-specific pharmacy prescriptions.All VF/VT OHCA of presumed cardiac aetiology in whom resuscitation was attempted.Any
Carew et al 200742 USARetrospective cohort1043Jan 1999– Dec 2003Survival to hospital dischargeNumber of chronic conditions.Ambulance patient care records.All VF cardiac arrest patients who had an arrest of presumed cardiac aetiology/heart disease.≥18
Corrada et al 201330 ItalyProspective cohort632004–2009Neurological outcome at dischargeHeart disease.Unclear.OHCA patients admitted to cardiac intensive care unit alive.Unclear
de Vreede-Swagemakers et al 199831 NetherlandsProspective cohort288Jan 1991–Dec 1995Survival to hospital dischargeCardiac history.Patients general practitioner.All OHCA where CPR was attempted by EMS and arrest was not due to trauma or intoxication or patient in terminal stage of disease.20–75
Dickey and Adgey 199232 Northern Ireland (UK)Prospective cohort281Jan 1966–Dec 1987In-hospital mortalityCerebrovascular accident, myocardial infarction.Unclear.All OHCA patients with an initial rhythm of VF.Any
Dumas et al 20178 USAProspective cohort1166Jan 2007– Dec 2013Survival to hospital discharge, neurological outcome at discharge (CPC)CCI=0,1,2,3, atrial fibrillation, cancer, cerebrovascular accident, congestive cardiac failure, coronary artery disease, diabetes, gastrointestinal disease, heart disease, HIV, hypercholesterolaemia, hypertension, kidney disease, liver disease, lung disease, mental health, metabolic disease, myocardial infarction, non-cardiac history, non-neurological history, peripheral artery disease, prior cardiac arrest, tissue/inflammatory disease, valvulopathy.Ambulance patient care records.Non-traumatic OHCA with initial rhythm of VF.≥18
Herlitz et al 199534 SwedenProspective cohort4881981–1992In-hospital mortalityMyocardial infarction, angina pectoris, hypertension, diabetes, congestive heart failure, cerebrovascular disease, asthma.Unclear.All OHCA patients with initial rhythm of VF who were hospitalised alive.Any
Hirlekar et al 201838 SwedenRetrospective cohort12 0122011–201530-day survivalCCI=0–2, 3–4, 5–6,>6, cancer, cerebrovascular disease, chronic pulmonary disease, congestive heart failure, connective tissue disorder/rheumatic, dementia, diabetes, diabetes (with complications), liver disease (mild), myocardial infarction, paraplegia/hemiplegia, peptic ulcer disease, peripheral vascular disease, renal disease.National Patient Registry.All bystander-witnessed patients with OHCA.≥18
Iqbal et al 201515 UKProspective cohort1742011–2013Neurological outcome (modified Rankin Scale, mRS) at dischargeCCI.National Institute for Cardiovascular Outcomes Research database.All OHCA patients who were brought to emergency department with ROSC.Any
Kang et al 201720 South KoreaRetrospective cohort341Jan 2009 – Dec 2014Survival to hospital discharge, neurological outcome (CPC)Cancer. Electronic medical records.All non-traumatic OHCA. Cases of hanging, intoxication and drowning were excluded.≥18
Larsson et al 200513 SwedenProspective cohort1377Oct 1980–Oct 2003Survival to hospital dischargeAngina pectoris, diabetes, myocardial infarction.Hospital records and general practitioner.All OHCA in whom resuscitation was attempted and patients were admitted to hospital alive.Any
Lee et al 201811 Japan, Singapre, South Korea, Malaysia, Taiwan, Thailand UAERetrospective cohort19 0442009–2012Survival to hospital discharge, neurological outcome at discharge (CPC)1, 2 or three conditions, heart diseaseHospital records, ambulance reports and ambulance dispatch records.All non-traumatic OHCA where resuscitation was commenced and where patient’s medical history was known.Any
Parry et al 201744 CanadaRetrospective cohort10 0972012–2014Survival to hospital discharge, neurological outcome (mRS)DiabetesIn-hospital records.All OHCA’s treated by ambulance services that had data on diabetes status.≥18
Roedl et al 201735 AustriaProspective cohort1068Jan 2005–Jan 20126-month neurological outcome (CPC)CCI=1,≥4, liver cirrhosis.Hospital screening.All OHCA patients admitted to the emergency department after ROSC.Any
Salam et al 20183 DenmarkProspective cohort666Jun 2002–201130-day mortalityCCI ≥1, cancer, cancer (metastatic), cerebrovascular disease, congestive heart failure, chronic kidney disease, connective tissue disease, coronary disease, dementia, diabetes, diabetes (with complications), gastric/duodenal ulcer, hemiplegia, hypercholesterolaemia, hypertension, liver disease, malignant haematological disease, acute myocardial infarction, peripheral artery disease, psychiatric disorder, pulmonary disease.National patient registry and chart review.Comatosed patients
(GCS<8), who were successfully resuscitated from OHCA, admitted and treated with TTM (32–36
C) for 24 hours.
Søholm et al 201540 DenmarkRetrospective cohort25272007–2011Survival to hospital dischargeCCI 1, 2,≥3, cancer, cancer (metastatic), cerebrovascular disease, congestive heart failure, diabetes, diabetes (with complications), hemiplegia, ischaemic heart disease, liver disease (mild), moderate/severe liver disease, moderate/severe renal disease, peptic ulcer, peripheral vascular disease, rheumatological disease.National Patient Registry.All OHCA of any aetiology with attempted resuscitation by EMS.≥18
Terman et al 201512 USARetrospective cohort588/558Jan 2005–Sept 2012Neurological outcome (CPC)CCI (continuous), CCI=1, CCI=2, AIDS, any tumour, cardiovascular disease, chronic pulmonary disease, congestive heart failure, connective tissue disease, dementia, diabetes, diabetes (with end organ damage), hemiplegia, leukaemia/lymphonma, mild liver disease, moderate/severe liver disease, moderate/severe renal disease, myocardial infarction, peptic ulcer disease, peripheral occlusive vascular disease, tumour (metastatic).Electronic health records.All non-traumatic OHCA patients that presented to the emergency department.≥18
Winther-Jensen et al 201614 Europe, AustraliaPost hoc analysis of clinical trial9392010–2013Neurological outcome (CPC) at 6 monthsModified CCI (mCCI): mCCI=1, mCCI=2, mCCI ≥3.Unclear.Comatosed patients with OHCA admitted to one of 36 intensive care units with ROSC.Unclear
Winther-Jensen et al
DenmarkRetrospective cohort9932007–201130-day mortality
Neurological outcome (CPC) at discharge
Cancer.National Patient Register.All patients with OHCA attended to by EMS and successfully resuscitated.≥18
  • CCI, Charlson Comorbidity Index; CPC, cerebral performance category; CPR, cardiopulmonary resuscitation; DNR, do not resuscitate; EMS, emergency medical services; GCS, Glasgow Coma Scale; OHCA, out-of-hospital cardiac arrest; ROSC, return of spontaneous circulation; TTM, therapeutic temperature management; VF, ventricular fibrillation; VT, ventricular tachycardia.