Table 2 Comparison the characteristics between ≥65 years and < 65 years patients experiencing AMI

Age, years

76.7 ± 6.9

57.8 ± 5.2

< 0.001

Male, n (%)

112 (62.1)

56 (91.8)

0.012

 Smoking

67 (42.1)

54 (88.5)

< 0.001

 Preexisting coronary artery disease

67 (42.1)

39 (63.9)

0.768

 COPD

26 (16.4)

9 (14.8)

0.968

 Lung cancer

16 (10.1)

3 (4.9)

0.203

 Diabetes

65 (40.9)

43 (70.5)

< 0.001

 Hypertension

99 (62.3)

29 (47.5)

0.008

 Hypercholesterolemia

29 (18.2)

24 (39.3)

0.002

 Chronic heart failure

6 (3.8)

1 (1.6)

0.376

 Cerebrovascular disease

22 (13.8)

4 (6.6)

0.115

 Chronic renal failure

6 (3.8)

1 (1.6)

0.376

 Chronic liver disease

6 (3.8)

5 (8.2)

0.300

 Fever

95 (59.7)

46 (75.4)

0.224

 Cough and expectoration

79 (49.7)

40 (65.6)

0.143

 Chest pain

13 (8.2)

12 (42.1)

0.018

 Dyspnea

42 (26.4)

9 (14.8)

0.046

 Duration of symptoms

6.9 ± 6.7

5.2 ± 3.8

0.589

 NIV/IMV

17 (10.7)

4 (6.6)

0.255

 respiratory failure

41 (25.8)

6 (9.8)

0.001

 Impaired consciousness

3 (1.9)

0 (0.0)

0.376

 Respiratory rate ≥ 30/min

4 (2.5)

1 (1.6)

0.575

 SBP < 90 mmHg or DBP ≤60 mmHg

19 (11.9)

7 (11.5)

0.596

 T < 36 °C or ≥ 40 °C

2 (1.3)

2 (3.3)

0.308

 Heart rate ≥ 125 bpm.

2 (1.3)

1 (1.6)

0.108

 BUN ≥7 mmol/L

95 (59.7)

14 (22.9)

0.000

 WBC < 4.0 × 109/L or ≥ 10.0 × 109/L

71 (44.7)

41 (67.2)

0.002

 PLT < 10.0 × 109/L

14 (8.8)

5 (8.2)

0.562

 PH < 7.35

15 (9.4)

2 (3.3)

0.106

 Serum sodium < 130 mmol/L

50 (31.4)

8 (13.1)

0.005

 HCT < 30%

21 (13.2)

6 (9.8)

0.333

 Blood glucose ≥14 mmol/L

11 (6.9)

6 (9.8)

0.319

 Pleural effusion

122 (76.7)

53 (86.9)

0.482

 Bacterial pneumonia

126 (79.2)

49 (80.3)

0.892

 Viral pneumonia

3 (1.9)

2 (3.3)

0.425

 Fungal pneumonia

8 (5.0)

3 (4.9)

0.638

Died during hospital stay, n (%)

16 (10.1)

4 (6.6)

0.301

Length of stay, days

13.8 ± 8.9

12.3 ± 7.4

0.328