Silent Myocardial Infarction and Long-Term Risk of Frailty: The Atherosclerosis Risk in Communities Study

Figures & data

Table 1 Baseline (Visit-1, 1987–1989) Participant Characteristics Stratified by Myocardial Infarction Status

Characteristic	Non-MI	Silent MI	Clinical MI	P
	(N=4672)	(N=135)	(N=146)
Demographic Variables
Age, years	52.1 ± 5.1	53.5 ± 4.9	53.8 ± 5.4	<0.001
Male sex	1939 (41.5)	80 (59.3)	96 (65.8)	<0.001
Race (Black)	833 (17.8)	20 (14.8)	26 (17.8)	0.652
Physical activity score	2.5 ± 0.8	2.4 ± 0.7	2.5 ± 0.8	0.117
Education				<0.001
Less than high school	569 (12.2)	26 (19.3)	35 (24.0)
High school	1525 (32.6)	41 (30.4)	46 (31.5)
College	2578 (55.2)	68 (50.4)	65 (44.5)
Smoking				<0.001
Never	2335 (50.0)	49 (36.3)	52 (35.6)
Ever	1568 (33.6)	47 (34.8)	59 (40.4)
Current	769 (16.5)	39 (28.9)	35 (24.0)
Drinking				0.405
Never	1090 (23.3)	24 (17.8)	33 (22.6)
Ever	638 (13.7)	31 (23.0)	27 (18.5)
Current	2944 (63.0)	80 (59.3)	86 (58.9)
Income, US$				0.213
<16,000	518 (11.1)	11 (8.1)	21 (14.4)
16,000–35,000	1546 (33.1)	51 (37.8)	55 (37.7)
>35,000	2608 (55.8)	73 (54.1)	70 (47.9)
Physiological and Lab Variables
Body mass index, kg/m2	27.0 ± 4.8	28.4 ± 4.8	28.4 ± 4.4	0.002
SBP, mmHg	115.9 ± 15.5	120 ± 16.8	119.7 ± 17	<0.001
DBP, mmHg	72.3 ± 9.9	74.5 ± 11.1	74.6 ± 10.5	0.002
Heart rate,/min	65.4 ± 9.5	64.6 ± 9.2	65 ± 8.9	0.615
Total cholesterol, mmol/l	5.4 ± 1.0	5.6 ± 1.0	5.8 ± 1.2	<0.001
HDL, mmol/l	1.4 ± 0.4	1.2 ± 0.4	1.2 ± 0.4	<0.001
LDL, mmol/l	3.5 ± 1.0	3.7 ± 0.9	3.8 ± 1.1	<0.001
Triglycerides, mg/dl	1.4 ± 0.9	1.5 ± 0.8	1.8 ± 1.0	<0.001
Creatinine, mg/mL	1.1 ± 0.2	1.1 ± 0.2	1.1 ± 0.2	<0.001
Blood glucose,mmol/l	100.8 ± 21.7	105.9 ± 34.7	106.6 ± 27.2	<0.001
Chronic Medical Conditions
Hypertension	880 (18.9)	36 (26.7)	56 (38.6)	<0.001
Diabetes mellitus	178 (3.8)	6 (4.5)	16 (11.0)	0.001
Cancer	227 (4.9)	9 (6.7)	7 (4.8)	0.662
COPD	128 (2.7)	9 (6.7)	9 (6.3)	0.008
Coranary heart disease	58 (1.3)	4 (3.1)	29 (20.7)	<0.001

Notes: Values are expressed as n (%), mean ± SD, and median (25th, 75th).

Abbreviations: MI, myocardial infarction; SBP, systolic blood pressure; DBP, diastolic blood pressure; HDL, high density lipoprotein; LDL, Low density lipoprotein; COPD, chronic obstructive pulmonary disease.

Figure 1 The prevalence of frailty in different MI status. *P<0.001. ^#P<0.001.

Abbreviation: MI, myocardial infarction.

Table 2 Adjusted ORs (95% CI) for the Association of Silent MI and Clinical MI with Incident Frailty

Diagnose	Unadjusted		Model 1		Model 2		Model 3
	OR (95% CI)	P	OR (95% CI)	P	OR (95% CI)	P	OR (95% CI)	P
MI status		<0.001		<0.001		<0.001		<0.001
Non-MI	Ref.	-	Ref.	-	Ref.	-	Ref.	-
Silent MI	2.773 (1.716–4.483)	<0.001	2.788 (1.708–4.550)	<0.001	2.423 (1.432–4.099)	0.001	2.243 (1.307–3.850)	0.003
Clinical MI	3.111 (1.990–4.862)	<0.001	3.032 (1.912–4.808)	<0.001	2.062 (1.210–3.513)	0.008	2.164 (1.259–3.721)	0.005

Notes: Model 1: adjusted by age, sex, center-race. Model 2: adjusted by model 1 plus education (<high school, high school, or >high school), annual household income (<16,000, 16,000 to 35,000, >35,000), and body mass index, smoking (never, former, current), drinking (never, former, current), systolic blood pressure, heart rate. Model 3: adjusted by model 2 plus physical activity score, total cholesterol, low density lipoprotein, high density lipoprotein, triglycerides, creatinine, hypertension, diabetes, and coronary heart disease. Unexplained variables are regarded as continuous variables.

Abbreviations: MI, myocardial infarction; OR, odds ratio; CI, confidence interval.

Figure 2 Adjusted ORs (95% CIs) for the association of MI status with incident frailty in different subgroups. Model was adjusted by age, sex, center-race, education (<high school, high school, or >high school), annual household income (<16,000, 16,000 to 35,000, >35,000), and body mass index, smoking (never, former, current), drinking (never, former, current), systolic blood pressure, heart rate, physical activity score, total cholesterol, low density lipoprotein, high density lipoprotein, triglycerides, creatinine, hypertension, diabetes, and coronary heart disease.

Abbreviations: MI, myocardial infarction; OR, odds ratio; CI, confidence interval.

Table 3 Direct and Indirect Effects of Clinical MI on Frailty

Effect	Variables	β Coefficient	95% CI	SE
Direct	Clinical MI	0.394	0.160–0.628	0.120
Indirect	Composite cognition score	0.079	0.035–0.121	0.015
Indirect	LVEF	0.101	0.056–0.397	0.031
Indirect	Serum creatinine	0.034	0.010–0.098	0.009

Notes: β coefficient was calculated by standard regression equation. Composite cognition score was calculated by mean of Digit Symbol Substitution Test Z score, Word Fluency Test Z score, and Delayed Word Recall Z score.

Abbreviations: MI, myocardial infarction; LVEF, left ventricular ejection fraction.

Figure 3 Direct and indirect effects of silent MI on frailty. β coefficient was calculated by standard regression equation. Composite cognition score was calculated by mean of Digit Symbol Substitution Test Z score, Word Fluency Test Z score, and Delayed Word Recall Z score.

Abbreviations: MI, myocardial infarction; LVEF, left ventricular ejection fraction; CI, confidence interval; SE, standard error.