Length of Stay and Short-Term Outcomes in Patients with ST-Segment Elevation Myocardial Infarction After Primary Percutaneous Coronary Intervention: Insights from the China Acute Myocardial Infarction Registry

Figures & data

Table 1 Baseline Characteristics for Patients Stratified by LOS

Variables	LOS≤7d (n=1193)	LOS>7d (n=2422)	P value
Patient demographics
Age, yrs	58.52±11.53	60.56±11.87	<0.001
Female	210 (17.6)	489 (20.0)	0.064
Currently single	27 (2.3)	93 (3.9)	0.015
Self-paying medication	111 (9.8)	169 (7.2)	0.008
BMI, kg/m^2	24.45 (22.57, 26.04)	24.22 (22.49, 26.12)	0.217
Medical history
Diabetes	221 (19.3)	425 (18.1)	0.407
Hypertension	552 (47.1)	1147 (48.1)	0.593
Hyperlipidemia	71 (6.6)	157 (7.2)	0.493
Current smoker	680 (57.2)	1209 (50.1)	<0.001
Previous Angina	229 (19.2)	456 (18.8)	0.791
Previous myocardial infarction	49 (4.1)	117 (4.8)	0.329
Previous heart failure	2 (0.2)	23 (0.9)	0.008
Previous stroke	90 (7.5)	162 (6.7)	0.342
Previous PCI	58 (4.9)	107 (4.4)	0.548
Previous CABG	2 (0.2)	5 (0.2)	—
Previous renal dysfunction	4 (0.3)	13 (0.5)	0.566
Chronic obstructive pulmonary disease	10 (0.8)	36 (1.5)	0.102
Presenting characteristics
Weekend admission	306 (25.6)	696 (28.7)	0.051
Symptom onset to admission time >12h	100 (8.4)	181 (7.5)	0.340
Heart rate	75.78±15.41	75.14±17.56	0.263
Systolic blood pressure, mmHg	131.70±24.84	127.79±25.86	<0.001
Killip class >I	158 (13.3)	452 (18.7)	<0.001
Cardiac arrest	6 (0.5)	36 (1.5)	0.009
LVEF (%)	55.75±8.50	53.54±9.71	<0.001
Creatinine, μmol/L	73.00 (62.00, 86.00)	73.00 (61.00, 87.33)	0.826
Hemoglobin, g/L	143.12±17.80	140.41±19.32	<0.001
Leukocyte count, ×10^9/L	10.63±3.46	10.71±3.44	0.508
Na^+, mmol/L	139.37±3.65	139.30±4.51	0.621
K^+, mmol/L	3.89±0.49	3.93±0.50	0.019
Procedural and angiographic characteristics
Transfemoral approach	193 (16.4)	282 (12.1)	<0.001
Three-vessel or left main disease	365 (31.2)	834 (36.1)	0.004
Left main or LAD related-infarction	557 (46.8)	1239 (51.5)	0.008
Preprocedural TIMI flow grade 0	845 (70.8)	1786 (73.7)	0.064
Stent type			<0.001
DES	940 (79.1)	2079 (86.2)
BMS	191 (16.1)	186 (7.7)
Without stent implantation	57 (4.8)	148 (6.1)
Postprocedural TIMI flow grade 3	1153 (97.3)	2294 (95.4)	0.007
Periprocedural complications	49 (4.1)	185 (7.6)	<0.001
GP IIb/IIIa inhibitor	435 (36.7)	1209 (50.2)	<0.001
IABP insertion	12 (1.0)	151 (6.2)	<0.001
In-hospital adverse events
New-onset heart failure	33 (2.8)	256 (10.6)	<0.001
Recurrent myocardial ischemia	3 (0.3)	24 (1.0)	0.026
Recurrent myocardial infarction	3 (0.3)	2 (0.1)	0.419
Stroke	2 (0.2)	12 (0.5)	0.227
Major bleeding	6 (0.5)	49 (2.0)	<0.001
Medications at discharge
Dual antiplatelet therapy	1173 (99.0)	2376 (98.4)	0.151
Statins	1106 (98.8)	2241 (98.8)	0.968
ACE inhibitors/ARB	758 (64.2)	1423 (59.5)	0.007
β-blockers	848 (71.7)	1792 (74.7)	0.051
Hospital characteristics
Province-level hospitals	802 (67.2)	888 (36.7)	<0.001
Number of beds
≤100	418 (35.0)	1155 (47.7)	<0.001
101–300	719 (60.3)	1059 (43.7)
>300	56 (4.7)	208 (8.6)
Hospital region
North	796 (66.7)	1615 (66.7)	0.980
South	397 (33.3)	807 (33.3)
Hospital expenses, Ұ	76,749.34 (64,407.56, 90,846.00)	88,438.50 (72,440.30, 107,972.81)	<0.001

Note: Data are presented as n (%), mean ± SD or median (quartiles).

Abbreviations: LOS, length of stay; BMI, body mass index; PCI, percutaneous coronary intervention; CABG, coronary artery bypass graft; LVEF, left ventricular ejection fraction; LAD, left anterior descending; TIMI, Thrombolysis In Myocardial Infarction; DES, drug-eluting stents; BMS, bare-metal stents; GP, glycoprotein; IABP, intra-aortic balloon pump; ACE, angiotensin converting enzyme; ARB, angiotensin II receptor blocker.

Table 2 Independent Predictors of Prolonged Length of Stay (LOS>7d)

Variables	Adjusted OR	95% CI	P value
Patient characteristics
Age (per 1 year increase)	1.012	(1.006, 1.019)	<0.001
BMI (per 1kg/m^2 increase)	0.985	(0.970, 0.999)	0.042
Medical history
Prior heart failure	5.593	(1.587, 19.715)	0.007
Presenting characteristics
Weekend admission	1.386	(1.232, 1.559)	<0.001
Systolic blood pressure (per 1mmHg increase)	0.996	(0.994, 0.999)	0.004
Killip class>I	1.263	(1.015, 1.571)	0.036
Cardiac arrest at admission	1.782	(1.017, 3.121)	0.044
LVEF (per 1% increase)	0.978	(0.965, 0.990)	0.001
Leukocyte count (per 10^9/L increase)	1.031	(1.004, 1.058)	0.025
Procedural and angiographic characteristics
Left main or LAD related infarction	1.187	(1.039, 1.357)	0.012
GP IIb/IIIa inhibitor	1.259	(1.031, 1.537)	0.024
IABP insertion	3.529	(2.195, 5.675)	<0.001
Hospital characteristics
Prefecture- and county-level hospitals	5.979	(3.308, 10.807)	<0.001
Number of beds
101–300 vs ≤100	1.262	(0.721, 2.209)	0.416
>300 vs ≤100	3.609	(1.127, 11.557)	0.031

Abbreviations: LOS, length of stay; BMI, body mass index; LVEF, left ventricular ejection fraction; LAD, left anterior descending; GP, glycoprotein; IABP, intra-aortic balloon pump; OR, odds ratio; CI, confidence interval.

Table 3 Association Between LOS and 30-Day Outcomes

Outcomes	Univariate Analysis		Multivariate Analysis
	Unadjusted OR (95% CI)	P value	Adjusted OR (95% CI)	P value
MACCE	1.328 (0.913, 1.931)	0.138	1.085 (0.710, 1.657)*	0.706
All-cause readmission	1.212 (0.844, 1.740)	0.298	1.060 (0.704, 1.594)*	0.781
Resting at home	1.404 (1.215, 1.623)	<0.001	1.003 (0.849, 1.185)*	0.973
Medication adherence	0.825 (0.706, 0.964)	0.015	0.817 (0.687, 0.971)^†	0.022

Notes: *Adjusted for patient demographics, medical history, presenting characteristics, procedural and angiographic characteristics, in-hospital adverse events, medications at discharge, and hospital characteristics; ^†Adjusted for patient demographics, medical history, presenting characteristics, procedural and angiographic characteristics, in-hospital adverse events, and hospital characteristics.

Abbreviations: LOS, length of stay; MACCE, major adverse cardiac and cerebrovascular events; OR, odds ratio; CI, confidence interval.

Figure 1 30-day clinical outcomes in different LOS groups. (A) MACCE. (B) Readmission. (C) Functional status. MACCE was defined as the composite of cardiac death, cardiovascular readmission, recurrent myocardial infarction, and stroke.

Abbreviations: MACCE, major adverse cardiac and cerebrovascular events; LOS, length of stay; MI, myocardial infarction.

Figure 2 Comparison of medication usage between at and after discharge in different LOS groups. (A) Dual antiplatelet therapy. (B) Statins. (C) ACE inhibitors/ARB. (D) β-blockers.

Abbreviations: LOS, length of stay; ACE, Angiotensin Converting Enzyme; ARB, angiotensin receptor blockers.