Table 1 Characteristics of the included studies (N = 14)

Chan Hyeong Kim 2022 [15]

Retrospective cohort

South Korea

Elderly patients who underwent primary isolated CABG procedure

508

67.3 ± 9.7

M = 78%

F = 22%

24.7 ± 3.6

297 (58.5%)

337 (66.3%)

257 (50.6%)

45 (8.9%)

59 (11.6%)

23 (4.5%)

NR

NR

Median 1.3 (0.9–2.3)

Patients’ laboratory data and vital signs

Early mortality rate, Post operative complications, 1- and 3-year survival rates, 1- and 3-year cumulative incidence rates of MACCE

6 (moderate risk)

Diem T. T. Tran 2018 [16]

Retrospective Cohort Study

Canada

≥ 40 years undergoing CABG

40 083

65.84 ± 9.85

M = 79.6%

F = 20.4%

Frail – 3179 (36.1%)

Not frail – 8966 (28.7%)

Frail – 4909 (55.8% )

Not frail – 13,999 (44.8%)

Frail − 8045 (91.4%)

Not frail – 26,984 (86.3%)

NR

Frail

≥ 50–19,746 (63.1)

35–49–7896 (25.2)

20–34–3084 (9.9)

< 20–554 (1.8)

Not frail

≥ 50–5237 (59.5)

35–49–2348 (26.7)

20–34–1010 (11.5)

< 20–208(2.4)

NR

Frail – 856 (9.7%)

Not frail − 1899 (6.1%)

NR

NR

NR

Johns Hopkins Adjusted Clinical Groups (ACG) indicator

Mortality rates

4 (moderate risk)

Daniel Reichart 2018 [17]

Prospective Cohort study

16 European centres of cardiac surgery - Finland, France, Italy, Germany, Sweden and the UK.

Elderly patients aged 65 years and above undergoing isolated CABG

6156

66.4 ± 9.6

M = 83%

F = 17%

Class 1–2–27.6 ± 4.1

Class 3–4–27.5 ± 4.2

Class 5–7–27.7 ± 4.2

Class 1–2–740 (30.7%)

Class 3–4–1170 (33.0%)

Class 5–7–77 (38.5%)

NR

NR

Class 1–2–619 (25.7%)

Class 3–4–1146 (32.4%)

Class 5–7–86 (43.0%)

Class 1–2–94 (3.9%)

Class 3–4–242 (6.8%)

Class 5–7–19 (9.5%)

Class 1–2–146 (6.1%)

Class 3–4–337 (9.5%)

Class 5–7 − 33 (16.5%)

NR

NR

Class 1–2–2.3 ± 3.1

Class 3–4–3.2 ± 4.5

Class 5–7–7.4 ± 9.4

Clinical Frailty Scale (CFS)

hospital/30-day death, Length of stay in ICU, postoperative atrial fibrillation, Stroke, Prolonged inotropic support, Deep sternal wound infection, KDIGO acute kidney injury, Renal replacement therapy, E-CABG bleeding grades 2–3

7 (low risk)

Joshua Solomon 2021 [18]

Prospective Cohort study

CaNRda

Elderly patients (60 years and above) undergoing urgent or elective isolated CABG

500

71.4 ± 6.4 years

M = 79%

F = 21%

Frail – 27.6 ± 5.6

Not frail − 28.1 ± 4.3

Frail − 39 (56%)

Not frail − 43 (33%)

Frail – 58 (83%)

Not frail − 91 (69%)

Frail − 56 (80%)

Not frail - 95 (72%)

Frail − 17 (24%)

Not frail – 21 (16%)

Frail − 7 (10%)

Not frail – 8 (6%)

Frail − 10 (14%)

Not frail – 14 (11%)

NR

NR

Frail – 4.5 ± 3.5

Not frail – 2.4 ± 2.4

Essential Frailty Toolset (EFT)

all-cause mortality, postoperative hospital length of stay ≥ 14  days, discharge to a healthcare facility, all-cause readmission at 30  days

5 (moderate risk)

Martyna Kluszczyńska 2021 [19]

Prospective Cohort study

Poland

Elderly patients (60 years and above) qualified for CABG

180

69.3 ± 6.2

M = 69%

F = 31%

NR

30.6%

60.0%

NR

NR

NR

NR

NR

NR

NR

Tilburg Frailty Indicator (TFI)

impact of frailty syndrome on the prognosis of patients after CABG

7 (low risk)

Martyna Kluszczynska 2021 [20]

Prospective observational study

Poland

Elderly patients (60 years and above) qualified for CABG

108

70.1 ± 6.4

M = 69.4%

F = 31.5%

78.3 ± 13.3

NR

NR

NR

NR

NR

NR

NR

NR

NR

Tilburg Frailty Indicator (TFI)

Influence of frailty syndrome on kinesiophobia after CABG according to the gender of patients.

Ajar Kochar 2023[21]

retrospective cohort study

USA

Elderly patients underwent CABG

13,554

median age was 69 years (IQR-63,72)

M = 98.6%

F = 1.4%

NR

Frail – 4263 (67.0)

Non frail – 870 (29.3))

Frail − 6251 (98.2)

Non frail – 1313 (44.2)

NR

Frail – 2042 (32.1)

Not frail – 322 (10.8)

NR

Frail – 3375 (53.0

Not frail (10 (0.3)

NR

NR

NR

Veterans Administration Frailty Index (VA-FI)

5-year all-cause mortality, days alive and out of the hospital within the first postoperative year, 30-day, 90-day and 1-year mortality

6 (moderate risk)

Arum Lim 2022[22]

retrospective cohort study

South Korea

Adults > 19 years who underwent CABG surgery

896

66.0 ± 9.0

M = 78.0%

F = 22.0%

24.7 ± 3.2

498 (55.6%)

617 (68.9%)

295 (32.9%)

99 (11.0%)

NR

18 (2.1%)

2.3 ± 1.9

NR

NR

Frailty Index-Laboratory (FI-LAB)

association between laboratory based-frailty and patient health outcomes after CABG surgery

5 (moderate risk)

Vishal Dobaria 2020[23]

retrospective cohort study

California, USA

Patients ≥ 18 years undergoing isolated coronary artery bypass grafting (CABG)

2,137,618

67.4 ± 10.7

M = 72.4%

F = 27.6%

NR

Frail – 30,533 (35.6)

Not frail – 846,458 (39.6)

Frail − 51,887 (60.4)

Not frail − 1,646,618 (77.0)

NR

Frail – 34,913 (40.7)

Not frail – 474,571 (22.2)

NR

Frail – 26,768 (31.2)

Not frail – 572,458 (26.8)

NR

Frail – 3.8 ± 2.1

Not frail – 2.9 ± 1.8

NR

Johns Hopkins Adjusted Clinical Groups (ACG) indicator

impact of frailty on in-hospital mortality, complications, resource use, length of stay, hospitalization costs and trends in mortality.

3 (high risk)

Nicholas J. Goel 2020[24]

Prospective Cohort study

USA

Adult (age ≥ 18 years) patients undergoing valve replacement surgery, coronary artery bypass grafting (CABG), or both

1,507,899

Median

70 (65–75)

M = 67.9%

F = 32.1%

NR

Frail – 19,333 (26.5%)

Non frail – 443,153 (30.9%)

NR

NR

Frail – 12,164 (16.7%)

Non frail – 35,447 (2.4%)

NR

NR

Frail

< 2–33,253 (45.7%)

2–3–25,498 (35.0%)

> 3–14,067 (19.3%)

Non frail

< 2–920,461 (64.1%)

2–3–244,394 (17.0%)

> 3–270,226 (18.8)

NR

NR

Johns Hopkins Adjusted Clinical Groups (ACG) indicator

in-hospital mortality, in-hospital complications, FTR – Failure to Rescue, nonhome discharge, 30-day readmission, length of hospitalization, and hospital costs

5 (moderate risk)

Mehrnoosh Bakhtiari 2024

Prospective Cohort study

Iran

patients aged over 60 years undergoing elective CABG

170

Median

66 (62–70)

M = 75.3%

F = 24.7%

Frail 26.1 ± 3.3

Not frail 26.1 ± 3.2

Frail − 29 (25.9%)

Not frail – 20 (34.5%)

NR

NR

NR

NR

Frail – 30 (51.7%)

Not frail – 52 (46.4%)

NR

NR

Frail 1.9 (1.5–2.4)

Not frail – 1.5 (1.3–1.9)

Frail Scale and Clinical Frail scale

Length of ward hospitalization, Length of ICU Hospitalization, Pneumonia, Atrial fibrillation, Mortality, Sepsis, Euro score, Readmission

5 (moderate risk)

ANR Johnson 2024

retrospective cohort study

CaNRda

patients 18 years of age or older who underwent isolated CABG surgery

50,682

NR

M = 76.8%

F = 23.2%

Non frail – 28.6 (5.4)

Frail – 29.1 (6.0)

NR

NR

NR

NR

NR

NR

Non frail – 1.5 (1.3)

Frail – 3.2 (1.8)

Non frail – 2.7 (4.4)

Frail – 9.4 (6.8)

NR

Clinical frailty scale

Mortality, average hospital length of stay between initial surgery and discharge, readmission within one year of discharge, Charlson comorbidity score, Elixhauser score, ADG.

3 (high risk)

Aslihan Aykut MD 2022

Retrospective Cohort Study

Turkey

adult patients who underwent coronary artery bypass grafting (CABG) with a cardiopulmonary bypass (CPB) and aortic cross-clamp (CC)

455

Median 61 (53–68)

M = 82.2%

F = 17.8%

27.97 (25.3–30.8)

158 (34.7%)

201 (44.2%)

NR

NR

15 (3.3%)

15 (3.3%)

NR

NR

NR

preoperative frailty index

Acute Kidney Injury

4 (moderate risk)

Nozomu Sugimoto 2023

retrospective cohort study

Japan

adults aged ≥ 65 years and diagnosed with angina pectoris and acute myocardial infarction who had undergone CABG

35,015

Median

74 (69–78)

M = 74.4%

F = 25.6%

Not frail

< 18.5–1685 (4.9%)

18.5 to 25- 22,302(64.9%)

> 25–9921 (28.9)

Frail

< 18.5–52 (8.2%)

18.5 to 25–416(65.7%)

> 25–158 (25.0)

Not frail 14,755 (42.9%)

Frail

− 265 (46.6%)

Not frail - 20,301 (59.0%)

Frail

− 370 (58.5%)

Not frail 11,291 (32.8%)

Frail

− 170 (26.9%)

Not frail 11,575 (33.7%)

Frail − 176 (27.8%)

Not frail 977 (2.8%)

Frail

− 19 (3.0%)

NR

Not frail

0–5534 (16.1%)

1–11,004 (32.0%)

2–9588 (27.9%)

≥ 3–8256 (24.0%)

Frail

0–11 (1.7%)

1–79 (12.5%)

2–113 (17.9%)

≥ 3–430 (67.9%)

NR

NR

The Hospital Frailty Risk score (HFRS)

Discharge to home, Aspiration pneumonia, Delirium, Disuse syndrome, Heart failure, Sepsis, Stroke.

4 (moderate risk)