Machine learning model for predicting hospital-acquired functional decline in older patients with postoperative cardiovascular surgery

Table 1 Preoperative clinical characteristics of the patients, n (%)/mean ± SD

	Overall (n = 144)	HAFD group (n = 41)	Non-HAFD group (n = 103)	P value
Age (years)	76.1 ± 8.7	79.1 ± 6.6	74.9 ± 9.2	0.009
Sex (female)	55 (38.2)	22 (53.7)	33 (32.0)	0.026
BMI (kg/m2)	22.9 ± 3.2	23.6 ± 3.3	22.7 ± 3.1	0.105
Surgery type				0.056
CABG	63 (43.8)	12 (29.3)	51 (49.5)
Valve replacement	73 (50.7)	25 (61.0)	48 (46.6)
Combined	8 (5.6)	4 (9.8)	4 (3.9)
Comorbidity
Hypertension	110 (76.4)	30 (73.2)	80 (77.7)	0.722
Dyslipidemia	91 (63.2)	26 (63.4)	65 (63.1)	1.000
Stroke	16 (11.1)	3 (7.3)	13 (12.6)	0.535
Diabetes	59 (41.0)	14 (34.1)	45 (43.7)	0.388
Orthopedic disorders	40 (27.8)	13 (31.7)	27 (26.2)	0.647
COPD	5 (3.5)	2 (4.9)	3 (2.9)	0.939
Laboratory data
BNP (pg/mL)	246.1 ± 285.4	294.0 ± 321.6	227.1 ± 268.9	0.205
Creatinine (mg/dL)	1.2 ± 1.3	1.2 ± 1.1	1.3 ± 1.4	0.623
eGFR (mL/minute/1.73 m2)	54.0 ± 20.2	52.4 ± 20.2	54.7 ± 20.3	0.528
BUN (mg/dL)	21.0 ± 10.0	20.9 ± 9.8	21.1 ± 10.1	0.917
Hemoglobin (g/dL)	12.7 ± 2.1	12.3 ± 2.0	12.9 ± 2.1	0.148
CRP (mg/dL)	0.6 ± 1.3	0.4 ± 0.8	0.6 ± 1.5	0.423
EF (%)	55.3 ± 13.1	54.0 ± 14.5	55.8 ± 12.5	0.471
%VC (%)	91.6 ± 12.2	92.8 ± 9.4	91.2 ± 13.2	0.465
FEV1.0% (%)	78.7 ± 9.2	78.3 ± 10.1	78.9 ± 8.8	0.728
Walking speed (milliseconds)	1.1 ± 0.4	1.2 ± 0.5	1.1 ± 0.3	0.020
5-CS (second)	10.9 ± 4.2	11.5 ± 3.5	10.7 ± 4.4	0.310
SPPB balance score	3.8 ± 0.7	3.6 ± 0.8	3.8 ± 0.6	0.121
SPPB standing score	3.1 ± 1.2	3.3 ± 1.1	3.0 ± 1.3	0.342
SPPB walking score	3.6 ± 0.7	3.6 ± 0.8	3.6 ± 0.7	0.844
Grip strength (kg)	25.2 ± 8.4	23.1 ± 7.3	26.0 ± 8.7	0.058

The significance of differences between the hospital-acquired functional decline (HAFD) and non-HAFD groups was analyzed using t-tests or the χ² test. BMI: Body mass index; BNP: B-type natriuretic peptide; BUN: Blood urea nitrogen; CABG: Coronary artery bypass grafting; COPD: Chronic obstructive pulmonary disease; CRP: C-reactive protein; eGFR: Estimated glomerular filtration rate; EF: Ejection fraction; FEV1.0%: Forced expiratory volume % in one second; SPPB: Short physical performance battery; VC: Vital capacity.