The Relationship Between Body Mass Index and In-Hospital Mortality in the Contemporary Era of an Acute Myocardial Infarction Management

Figures & data

Table 1 Frequency Distribution of Baseline Characteristics by BMI Group in AMI Patients

BMI Groups Kg/m^2	≤19 Under-Weight	20–25 Normal-Weight	26–30 Over-Weight	31–35 Obese I Group	36–39 Obese II Group	≥ 40 Extremely Obese	Total	P-value
BMI kg/m^2, n
Unweighted^a	1519	1137	3347	6883	4596	7599	25,081
Weighted^b	7595	5685	16,735	34,415	22,980	37,995	125,405
Age Group, %								<0.001
18–44 yrs	1.3	2.4	5.0	7.6	9.9	11.6	8.3
45–59 yrs	9.0	14.7	27.4	33.5	34.1	35.7	31.1
60–74 yrs	28.6	30.0	42.2	41.7	41.9	42.8	40.6
75 yrs or older	61.2	52.9	25.5	17.3	14.0	10.7	20.1
Gender, %								<0.001
Female	61.3	42.6	37.4	36.5	39.4	50.1	43.0
Male	38.7	57.3	62.6	63.5	60.5	49.9	56.9
Race, %								<0.001
White	72.1	66.4	70.1	70.1	71.7	68.8	70.0
Non-white	22.8	27.1	23.2	22.7	21.3	24.6	23.3
Comorbidity, %
HTN	43.4	45.3	57.2	59.0	59.8	55.9	56.4	<0.001
CHF	21.5	19.3	14.5	13.5	15.1	17.6	15.9	<0.001
DM	16.1	29.1	37.4	40.9	42.8	47.2	40.7	<0.001
CRD	27.6	33.7	24.1	23.2	23.7	28.1	25.6	<0.001
COPD	42.3	27.5	19.7	21.3	23.2	29.3	25.4	<0.001
PVD	20.7	14.5	13.3	12.2	12.1	10.5	12.4	<0.001
Atrial Fibrillation/Flutter	28.9	27.7	15.8	15.0	15.7	18.5	17.7	<0.001
Prior MI	14.8	15.0	16.2	15.6	16.3	15.0	15.6	<0.001
Deyo-CCI, %								<0.001
1	7.6	11.6	19.4	19.7	19.3	14.6	16.9
2 or higher	92.4	88.4	80.6	80.3	80.7	85.4	83.1

Notes: ^aRepresents the number of observations in the NIS database. ^bRepresents total national estimates after applying sampling weights.

Abbreviations: CHF, congestive heart failure; COPD, chronic obstructive lung disease; CRD, chronic renal disease; Deyo-CCI, Deyo-Charlson Comorbidity Index; DM, diabetes mellitus; HTN, hypertension; MI, myocardial infarction; PVD, peripheral vascular disease.

Table 2 Frequency Distribution of Clinical Course and Outcomes by BMI Group

	≤19 Under-Weight	20–25 Normal-Weight	26–30 Over-Weight	31–35 Obese I Group	36–39 Obese II Group	≥ 40 Extremely Obese	Total	P-value
NSTEMI, %	82.1	79.1	71.3	72.9	73.8	79.0	75.6	<0.001
STEMI, %	18.2	21.2	29.2	27.7	26.5	21.4	24.4	<0.001
VT/VF	7.2	6.9	7.9	8.0	8.1	7.6	7.8	0.007
Coronary Angiography, %	38.1	49.9	75.0	77.0	77.2	72.1	71.7	<0.001
PCI, %	21.5	31.1	55.7	58.6	56.9	49.5	51.6	<0.001
CABG, %	1.1	2.1	2.7	2.7	2.6	1.8	2.3	<0.001
Thrombolytic Therapy %	0.9	0.4	1.3	1.0	1.1	1.1	1.1	<0.001
Mortality, %	9.2	6.4	3.3	2.7	2.6	3.6	3.6	<0.001
LOS (days), Mean ± SEM	6.11 ± 0.17	6.16 ± 0.21	4.14 ± 0.08	3.71 ± 0.05	3.78 ± 0.06	4.42 ± 0.06	4.25 ± 0.04	<0.001

Abbreviations: BMI, body mass index Kg/m²; CABG, coronary bypass graft; LOS, length of stay; NSTEMI, non-ST segment elevation myocardial infarction; PCI, percutaneous coronary intervention; STEMI, ST segment myocardial infarction; VF/VT, ventricular flutter/ventricular fibrillation.

Figure 1 Mortality rate via BMI groups.

Figure 2 Length of stay via BMI groups.

Table 3 Univariate (A) and Multivariate (B) Analysis for Predictors of in-Hospital Mortality, 2015–2016

Predictor	Odds Ratio (95% CI)	P-value
3A. Univariate Analysis
BMI kg/m^2 Group		<0.001
≤ 19	1.47 (1.29–1.67)	<0.001
20–25	1.00 (reference)	N/A
26–30	0.50 (0.44–0.57)	<0.001
31–35	0.40 (0.36–0.46)	<0.001
36–39	0.39 (0.34–0.44)	<0.001
≥40	0.54 (0.48–0.61)	<0.001
Age Group, years		<0.001
18–44	1.00 (reference)	N/A
45–59	2.43 (1.94–3.04)	<0.001
60–74	4.68 (3.77–5.83)	<0.001
≥75	9.00 (7.23–11.20)	<0.001
Deyo-CCI		<0.001
1	1.00 (reference)	N/A
2 or higher	3.42 (3.02–3.88)	<0.001
Gender		0.007
Male	1.00 (reference)	N/A
Female	1.09 (1.02–1.15)	0.007
Race		0.048
Non-white	1.00 (reference)	N/A
White	1.08 (1.00–1.16)	0.048
Comorbidities
Smoking Status
Non-Smokers	1.00 (reference)	N/A
Past-Smokers	1.66 (1.61–1.72)	<0.001
Current-Smokers	1.57 (1.52–1.61)	<0.001
Atrial Fibrillation/Flutter		<0.001
No	1.00 (reference)	N/A
Yes	2.26 (2.11–2.41)	<0.001
COPD		<0.001
No	1.00 (reference)	N/A
Yes	1.20 (1.12–1.28)	<0.001
CHF		<0.001
No	1.00 (reference)	N/A
Yes	1.86 (1.74–2.00)	<0.001
DM		0.357
No	1.00 (reference)	N/A
Yes	0.97 (0.91–1.03)	0.357
HTN		<0.001
No	1.00 (reference)	N/A
Yes	0.40 (0.38–0.43)	<0.001
PVD		<0.001
No	1.00 (reference)	N/A
Yes	1.58 (1.46–1.70)	<0.001
CRF		<0.001
No	1.00 (reference)	N/A
Yes	2.31 (2.17–2.45)	<0.001
Revascularization	0.51 (0.48–0.54)	<0.001
3B. Multivariate Analysis
BMI kg/m^2 Group		<0.001
≤19	1.34 (1.17–1.54)	<0.001
20–25	1.00 (reference)	N/A
26–30	0.61 (0.52–0.70)	<0.001
31–35	0.56 (0.49–0.64)	<0.001
36–39	0.56 (0.48–0.64)	<0.001
≥ 40	0.83 (0.73–0.94)	0.005
Age Group, years		<0.001
18–44 yrs	1.00 (reference)	N/A
45–59 yrs	2.36 (1.86–3.00)	<0.001
60–74 yrs	4.26 (3.38–5.39)	<0.001
75 yrs or older	6.94 (5.47–8.81)	<0.001
Gender		<0.001
Male	1.00 (reference)	N/A
Female	0.84 (0.79–0.90)	<0.001
Race		0.531
Non-white	1.00 (reference)	N/A
White	1.02 (0.95–1.11)	0.531
Deyo-CCI		<0.001
1	1.00 (reference)	N/A
2 or higher	2.42 (2.12–2.77)	<0.001
Comorbidities
Smoking Status
Non-Smokers	1.00 (reference)	N/A
Past-Smokers	1.63 (1.59–1.69)	<0.001
Current-Smokers	1.78 (1.71–1.85)	<0.001
Atrial Fibrillation/Flutter		<0.001
No	1.00 (reference)	N/A
Yes	1.60 (1.49–1.71)	<0.001
CHF		<0.001
No	1.00 (reference)	N/A
Yes	1.46 (1.35–1.57)	<0.001
COPD		<0.001
No	1.00 (reference)	N/A
Yes	0.86 (0.80–0.93)	<0.001
DM		<0.001
No	1.00 (reference)	N/A
Yes	0.81 (0.76–0.87)	<0.001
HTN		<0.001
No	1.00 (reference)	N/A
Yes	0.52 (0.48–0.55)	<0.001
PVD		<0.001
No	1.00 (reference)	N/A
Yes	1.18 (1.09–1.28)	<0.001
Renal failure		<0.001
No	1.00 (reference)	N/A
Yes	1.74 (1.63–1.86)	<0.001
Revascularization	0.69 (0.65–0.74)	<0.001

Abbreviations: BMI, body mass index kg/m²; CHF, congestive heart failure; COPD, chronic obstructive lung disease; CRD, chronic renal disease; Deyo-CCI, Deyo-Charlson Comorbidity Index; DM, diabetes mellitus; HTN, hypertension; PVD, peripheral vascular disease.