Table 3: Studies in final analysis.

InvestigatorsIndex conditionSampleDefinition of comorbidity
Surrogate terms
Diseases listed (instrument)Data sourceComorbidity used as

Afshinnia et al. [19]AMI = 220No definition
comorbid diseases, conditions, underlying diseases
HTN, DM, HF, sepsis, anemia, cardiorespiratory arrestPatient, family Clinician judgment
Medical records

Afzal et al. [34]HF No definition
comorbid conditions, risk factors
HTN, DM, Hx of MI/strokeClinician judgment
Medical records

Ariyarajah et al. [37]Stroke No definition
common medical comorbidities  
risk factors
Hx of stroke, Afib
CAD, MS, MR, dilated, restrictive, and hypertrophic cardiomyopathy, hyperlipidemia, DM, hyper/hypothyroid, COPD, HF, MI
Medical recordsCovariate

Castillo et al. [38]Stroke No definition
comorbid depression
DepressionClinical judgment using DSM-III criteriaPredictor
interaction term

Chin and Goldman [25]HF No definitionHx of HF, MI, HTN, DM
(Charlson Comorbidity Index)
Medical recordsPredictor and covariate

Freedland et al. [33]HF No definition
comorbid medical condition
Hx of HF, MI, anemia, arthritis, CAD, CVA, DM, GI disorder, HTN, COPD, sleep apnea, renal disease
Hx of 1 or more comorbid medical conditions
(Beck Depression Inventory)
Clinical judgment using the diagnostic interview schedule
Medical records
Predictor, covariate, outcome

Fulop et al. [26]HF No definition(Geriatric Depression Scale;  
Duke University severity of illness checklist)
Clinician judgment
Medical records

Goonewardena et al. [32]HF No definitionHTN, DM, COPD, CKD, Afib, depressionUnclearCovariate

Jiang et al. [31]HF = 1,006No definition
concomitant illnesses, clinical characteristics
Hx MI, DMMedical recordsCovariate

Kimmelstiel et al. [30]HF No definitionHTN, DMPatient
Medical records

Kishi et al. [36]Stroke No definition(Hamilton Depression Rating Scale)Patient
Clinician judgment using the DSM-III criteria

Sert Kuniyoshi et al. [20]AMI No definition

Lakkireddy et al. [21]AMI No definition
UnclearPredictor covariate

Malki et al. [29]HF No definitionHTN, DM, Hx MI, strokeClinician judgmentCovariate

Marrugat et al. [22]AMI No definition
clinical variables
CKD, COPD, DM, HTN, PVDUnclearCovariate

Mehta et al. [39]Stroke No definition
clinical data, other diseases, risk factors
HTN, DM, CHD, dyslipidemiaUnclearCovariate

Moroney et al. [40]Stroke No definition
risk factor
Angina, MI, HF, and valvular heart diseasePatient
Key informants
Medical record

Naylor et al. [28]HF No definition
medical conditions, health conditions
CAD, HTN, Afib, DM, pulmonary diseaseMedical recordCovariate

Quinn [23]AMI No definition
disease history  
clinical variables  
past medical history
Hx of Angina, CAD, HTN, DM, hyperlipidemia, smoking (past/current), previous MIMedical recordCovariate

Rehan et al. [24]AMI No definition
baseline demographics
Hx of CAD, HTN, HF, DMUnclearDescriptor

Rocha et al. [17]AMI No definition (Charlson Comorbidity Index for medical comorbidities;
SCID and IES-R for PTSD)
Medical record
Predictor, outcome

Romanelli et al. [18]AMI No definitionDepression
DM, COPD, HTN, hyperlipidemia, CKD,
(Beck Depression Index)
Clinician judgment using the DSM-III Medical record

Sakr et al. [27] HF No definition
risk factor
CAD, CKD, pneumonia, DM, HTN, HFUnclearCovariate

Shah et al. [41]Stroke No definition
clinical data
DM, HTN, hypercholesterolemia, CAD, Afib, Hx of strokeUnclearCovariate

Soman et al. [35]HF No definition
relevant clinical variables
CAD, Hx of MI
DM, HTN, lipid abnormalities
Clinician judgmentCovariate

Stead et al. [42]Stroke No definitionHTN, DM, Afib, Hx of TIA, and strokeUnclearDescriptor

AMI: acute myocardial infarction, Afib: atrial fibrillation, CAD: coronary artery disease, CHD: chronic heart disease, CKD: chronic kidney disease, COPD: chronic obstructive pulmonary disease, CVA: cerebral vascular accident, DM: diabetes mellitus, DSM-III: American psychiatric association diagnostic and statistical manual of mental disorders, 3rd edition, GI: gastrointestinal, HF: heart failure, HTN: hypertension, Hx: history, IES-R: impact of event scale-revised, MI: myocardial infarction, MS: mitral stenosis, MR: mitral regurgitation, PVD: peripheral vascular disease, SCID: structured clinical interview for DSM disorders, TIA: transient ischemic attack.
Diseases listed are in regular font. Instruments used in the study are in bold.