Ethnicity and acute myocardial infarction: risk profile at presentation, access to hospital management, and outcome in Norway

Figures & data

Figure 1 Flow chart of the dual-design study, incorporating comparative cross-sectional study and cohort study.

Figure 2 Regression line showing the association between concentration of serum high-density lipoprotein (HDL) and age.

Table 1 Clinical profile of patients with acute myocardial infarction (MI) of minority versus nonminority background

	Minority background n = 147 (%)	Nonminority background n = 588 (%)	Odds ratio	95% CI	P valuea
Current smokers	76 (51.7)	207 (35.2)	1.98	1.38–2.87	0.0002
Type 2 diabetes mellitus	40 (27.2)	72 (12.2)	2.67	1.68–4.23	0.0001
Male sex	126 (85.7)	416 (70.7)	2.48	1.49–4.28	0.0002
Hyperlipidemia	13 (8.8)	65 (11.0)	0.78	0.38–1.48	0.4630
History of hypertension	40 (27.2)	236 (40.1)	0.56	0.36–0.84	0.0038
Previous MI	25 (17.0)	127 (21.6)	0.74	0.44–1.21	0.2189
Previous stroke	11 (7.5)	54 (9.2)	0.80	0.37–1.60	0.5160
Previous PCI	20 (13.6)	73 (12.4)	1.11	0.62–1.92	0.6978
Previous ACBG	7 (4.8)	34 (5.8)	0.81	0.30–1.92	0.6297
Presence of STEMI	85 (57.8)	300 (51.0)	1.32	0.90–1.93	0.1396
		Minority Median (Q1–Q3)c	Nonminority Median (Q1–Q3)		P valueb
Age at MI (years)d		55.0 (47.0–62.0)	66.0 (56.0–77.0)		<0.00001
Cholesterol (mmol/L)		5.0 (4.3–5.9)	4.9 (4.1–5.6)		0.2767
Creatinine (μmol/L)		75.0 (63.0–91.0)	78 (66–93)		0.1857
HDL (mmol/L)		0.99 (0.88–1.15)	1.18 (0.97–1.42)		<0.00001
Maximum treponin (μmol/L)		2.13 (0.77–5.86)	1.67 (0.52–5.47)		0.2133

Notes:

a Chi-square test;

b Mann–Whitney U test;

c Q1: 25% quartile, Q3: 75% quartile.

d Excluding patients with previous MI (n = 152), the difference in median age between patients from a minority background and those who were indigenous Norwegians was 10 years (54 years vs 64 years), P = 0.001.

Abbreviations: ACBG, aortocoronary bypass graft; CI, confidence interval; HDL, high-density lipoprotein; PCI, percutaneous coronary intervention; STEMI, ST-segment elevation myocardial infarction.

Table 2 Gradient effect of age interval by quartiles and frequency of risk factors using the Mantel–Haenszel test of linear trend

	Age (years)
	≤54.0	54.0–61.9	62.0–74.9	≥75.0	Total
Minority
Yes	62	48	28	9	147
No	112	126	172	178	588
Total	174	174	200	187	735
Frequency (%)	35.6	27.5	14.0	4.8	20.0
ORa (95% CI)	1.00	0.69 (0.43–1.11)	0.29 (0.17–0.50)	0.09 (0.04–0.20)
Current smoker
Yes	115	85	59	24	283
No	59	89	141	163	452
Total	174	174	200	187	735
Frequency (%)	66.1	48.8	29.5	12.8	38.5
ORb (95% CI)	1.0	0.49 (0.31–0.77)	0.21 (0.14–0.34)	0.08 (0.04–0.13)
Male sex
Yes	150	146	145	101	542
No	24	28	55	86	193
Total	174	174	200	187	735
Frequency (%)	86.0	83.0	72.5	54.0	73.7
ORc (95% CI)	1.00	0.83 (0.44–1.57)	0.42 (0.24–0.74)	0.19 (0.11–0.32)
History of hypertension
Yes	34	65	89	88	276
No	146	109	111	99	459
Total	174	174	200	187	735
Frequency (%)	19.5	37.1	44.5	47.0	37.6
ORd (95% CI)	1.00	2.56 (1.54–4.28)	3.44 (2.11–5.64)	3.82 (2.32–6.29)
Type 2 diabetes mellitus
Yes	19	25	41	27	112
No	155	149	159	160	623
Total	174	174	200	187	735
Frequency (%)	10.9	14.3	20.5	14.4	15.2
ORe (95% CI)	1.00	1.37 (0.69–2.71)	2.10 (1.13–3.95)	1.38 (0.70–2.70)

Notes:

a Chi square of linear trend: 63.608, df = 1, P value < 0.0001;

b chi square of linear trend: 122.417, df = 1, P value < 0.0001;

c chi square of linear trend: 54.734, df = 1, P value < 0.0001;

d chi square of linear trend: 33.015, df = 1, P value < 0.0001;

e chi square of linear trend: 1.936, df = 1, P value = 0.1641.

Abbreviations: CI, confidence interval; df, degrees of freedom; OR, odds ratio.

Table 3 Risk factors differentiating patients with acute myocardial infarction of minority background versus those from nonminority background using the multivariate logistic model with a prognostic strategy

Predictors	Level	Odds ratio	95% confidence interval	Z	P value
Model A
Current smoker	Yes/no	1.92	1.30–2.83	3.30	0.001
Type 2 diabetes mellitus	Yes/no	3.26	2.03–5.25	4.87	<0.001
HDL cholesterol < 0.95 mmol	Yes/no	2.09	1.39–3.15	3.55	<0.001
Male sex	Yes/no	1.92	1.15–3.23	2.48	0.013
Treated hypertension	Yes/no	0.52	0.34–0.81	−2.93	0.003
Model B
Diabetes mellitus type 2	Yes/no	3.21	2.02–5.09	4.95	<0.001
Age < 54 years	Yes/no	3.54	2.39–5.23	6.31	<0.001

Note: Two-model presentation was used to avoid the problem of multicollinearity between the predictors of ethnicity.

Abbreviation: HDL, high-density lipoprotein.

Table 4 Hospital outcomes and mortality stratified on the nature of acute myocardial infarction ST-segment elevation myocardial infarction (STEMI) versus non-STEMI

	Minority background	Nonminority background	P value
STEMI (N = 385)	n = 85	n = 300
Hospital mortality	1 (1.2%)	20 (6.6%)	0.05
Hospital angiography	84 (99%)	287 (96%)	0.16
Hospital access to PCI	74 (87%)	241 (80.3%)	0.15
Hospital access to ACBG	0 (0%)	2 (0.6%)	0.60
Mors/patients daysa	2/41777	42/146800
Mortality rate (deaths per 10,000)	0.4787	2.861	0.004
Time delay to primary PCI, minutesb–d
Symptom-to-balloon time	177 (117–345)	255 (143–415)	0.003
Door-to-balloon time	36.5 (30–56)	34.0 (27–44)	0.06
Non-STEMI (N = 350)	n = 62	n = 288
Hospital mortality	1 (1.61%)	20 (6.9%)	0.11
Hospital angiography	61 (98.3%)	225 (78.1%)	0.0001
Hospital access to PCI	26 (41.9%)	107 (37.1%)	0.48
Hospital access to ACBG	1 (1.61%)	8 (2.7%)	0.50
Mors/patients days	4/29429	50/135237
Mortality rate (deaths per 10,000)	1.359	3.697	0.05

Notes:

a Median follow up time = 500 days;

b median with 25% and 75% quartile;

c Mann–Whitney U test;

d adjusting for age, sex, and smoking habit using the linear regression model, the differences in time delay to primary PCI in minutes continued to be significantly different for the minority group compared with the nonminority group (P value = 0.02).

Abbreviations: ACBG, aortocoronary bypass graft; PCI, percutaneous coronary intervention.

Table 5 Adjusted odds ratio (OR) for patients with acute myocardial infarction (AMI) with minority background versus those from nonminority background using a logistic regression model and Cox’s regression model, controlling for multi-confounders

End point	Minority vs nonminority	OR*	95% confidence interval	P value
Hospital mortalitya	Yes/no	0.45	0.10–2.03	0.298
Hospital angiographyb	Yes/no	3.8	0.48–30.1	0.206
Hospital PCIc	Yes/no	0.86	0.57–1.31	0.499
Hospital ACBGd	Yes/no	0.43	0.05–3.81	0.453
		HR**
500 days follow-up mortalitye	Yes/no	0.57	0.24–1.35	0.205

Notes:

* Estimated from the logistic regression model;

** estimated from Cox’s regression model;

a adjusting for the confounding effect of age;

b adjusting for the confounding effect of age, sex, and presence of STEMI versus non-STEMI AMI;

c adjusting for the confounding effect of age, sex, and presence of STEMI versus non-STEMI AMI;

d adjusting for the confounding effect of age and presence of diabetes mellitus;

e adjusting for the confounding effect of age, sex, and presence of STEMI versus non-STEMI AMI.

Abbreviations: ACBG, aortocoronary bypass graft; HR, hazard ratio; PCI, percutaneous coronary intervention.

Figure 3 Kaplan–Meier survival plot for patients with minority background versus indigenous Norwegian patients.

Note: Median follow-up time was 500 days after acute myocardial infarction (univariate analysis).