Pattern of Cardiovascular Comorbidity in COPD in a Country with Low-smoking Prevalence: Results from Two-population-based Cohorts from Sweden

Figures & data

Table 1a. Prevalence of characteristics among subjects with and without COPD with the fixed ratio criterion.

	Non-COPD n = 1679		COPD fixed ratio n = 160			COPD GOLD> =2 n = 72
	n	%	n	%	p value	n	%	P value
WSAS cohort	1,052	62.7%	96	60.0%		42	58.3%
OLIN cohort	627	37.3%	64	40.0%	0.507	30	41.7%	0.458
Mean age (years)	1679	50.2	160	60.6	<0.001	72	63.0	<0.001
<40 years	446	26.6%	13	8.1%		2	2.8%
40–60 years	745	44.4%	49	30.6%	<0.001	21	29.2%	<0.001
>60 years	488	29.1%	98	61.3%		49	68.1%
Women	895	53.3%	73	45.6%	0.063	30	41.7%	0.053
Never-smokers	919	54.8%	47	29.4%		14	19.4%
Ex-smokers	566	33.7%	71	44.4%	<0.001	34	47.2%	<0.001
Current smokers	193	11.5%	42	26.3%		24	33.3%
Ever-smokers:
< =10 pack-years	417	24.9%	25	15.6%	<0.001	9	12.5%	<0.001
< =20 pack-years	169	10.1%	23	14.4%		12	16.7%
< =30 pack-years	98	5.8%	27	16.9%		12	16.7%
>30 pack-years	75	4.5%	38	23.8%		25	34.7%
High school or less education^a	950	57.4%	111	70.7%	0.001	57	80.3%	<0.001
Exposure to gas dust or fumes at work	438	26.4%	57	36.5%	0.007	33	46.5%	<0.001
Mean BMI (Kg*m^−2)	1679	26.6	160	26.4	0.628	72	27.3	0.156
Underweight (BMI <20)	57	3.4%	4	2.5%	0.546	3	4.2%	0.735
Normal weight (20 ≤ BMI <25)	585	34.8%	58	36.3%	0.729	16	22.2%	0.031
Pre-obesity (25 ≤ BMI <30)	735	43.8%	75	46.9%	0.455	39	54.2%	0.090
Obesity (BMI ≥30)	302	18.0%	23	14.4%	0.252	14	19.4%	0.753

^a University as reference.

p value = for comparisons against non-COPD. For comparisons of proportions across two groups, the Chi-square or Fisher’s exact tests were used, as appropriate. For comparisons of proportions across more than two groups, the Mantel–Haenzel test-for-trend was used. The t-test was used for comparisons of means.

Table 1b. Prevalence of characteristics among subjects with and without COPD with the LLN criterion.

	Non-COPD n = 1735		COPD LLN n = 104			COPD with FEV1<LLN n = 57
	n	%	n	%	p value	n	%	p value
WSAS cohort	1,089	62.8%	59	56.7%		32	56.1%
OLIN cohort	646	37.2%	45	43.3%	0.217	25	43.9%	0.309
Mean age (years)	1,735	50.8	104	56.7	<0.001	57	60.7	<0.001
<40 years	442	25.5%	17	16.3%		3	5.3%
40–60 years	756	43.6%	38	36.5%	0.001	21	36.8%	<0.001
>60 years	537	31.0%	49	47.1%		33	57.9%
Women	934	53.8%	70	32.7%	<0.001	38	33.3%	0.002
Never-smokers	938	54.1%	28	26.9%		13	22.8%
Ex-smokers	592	34.1%	45	43.3%	<0.001	25	43.9%	<0.001
Current smokers	204	11.8%	31	29.8%		19	33.3%
Ever-smokers:
< =10 pack-years	424	24.5%	18	17.3%	<0.001	7	12.3%	<0.001
< =20 pack-years	180	10.4%	12	11.5%		8	14.0%
< =30 pack-years	107	6.2%	18	17.3%		9	15.8%
>30 pack-years	85	4.9%	28	26.9%		20	35.1%
High school or less education^a	986	57.7%	75	73.5%	0.002	45	80.4%	0.001
Exposure to gas dust or fumes at work	449	26.2%	46	45.1%	<0.001	28	49.1%	<0.001
Mean BMI (Kg*m^−2)	1735	26.6	104	26.3	0.460	57	27.0	0.469
Underweight (BMI <20)	59	3.4%	2	1.9%	0.578	1	1.8%	1.000
Normal weight (20 ≤ BMI <25)	605	34.9%	38	36.5%	0.751	16	28.1%	0.324
Pre-obesity (25 ≤ BMI <30)	761	43.9%	49	47.1%	0.543	30	52.6%	0.222
Obesity (BMI ≥30)	310	17.9%	15	14.4%	0.371	10	17.5%	0.950

^a University as reference.

p value = for comparisons against non-COPD. For comparisons of proportions across two groups, the Chi-square or Fisher’s exact tests were used, as appropriate. For comparisons of proportions across more than two groups, the Mantel–Haenzel test-for-trend was used. The t-test was used for comparisons of means.

Figure 1. Prevalence of ischaemic heart disease, medication for heart disease or hypertension (HT), and any heart disease, hypertension or medication for heart disease or hypertension. Left groups: fixed ratio criterion, right groups: LLN criterion. Medication refers to medicines for heart disease and/or hypertension.

Table 2a. Prevalence of comorbidities among subjects with and without COPD with the fixed ratio criterion.

	Non-COPD n = 1679		COPD fixed ratio n = 160			COPD GOLD> =2 n = 72
	n	%	n	%	p value	n	%	p value
Myocardial infarction	47	2.8%	8	5.0%	0.139	6	8.3%	0.019
Angina pectoris	39	2.3%	7	4.4%	0.113	4	5.6%	0.097
Coronary artery bypass graft	34	2.0%	5	3.1%	0.380	3	4.2%	0.192
Ischaemic heart disease	77	4.6%	13	8.1%	0.047	8	11.1%	0.021
Heart failure	6	0.4%	4	2.5%	0.008	4	5.6%	<0.001
Arrhythmia	85	5.1%	9	5.6%	0.758	5	6.9%	0.415
Any heart disease	198	11.8%	27	16.9%	0.061	14	19.4%	0.051
Hypertension (or medicines)	409	24.4%	65	40.6%	<0.001	40	55.6%	<0.001
Medication for heart disease	275	16.4%	41	25.6%	0.003	24	33.3%	<0.001
Medication for heart disease or HT	391	23.3%	64	40.0%	<0.001	37	51.4%	<0.001
Intermittent claudication	19	1.1%	6	3.8%	0.017	6	8.3%	<0.001
TIA or stroke	57	3.4%	8	5.0%	0.293	7	9.7%	0.014
Diabetes	70	4.2%	13	8.1%	0.021	8	11.1%	0.013

HT = Hypertension.

p value = for comparisons against non-COPD. For comparisons of proportions across two groups, the Chi-square or Fisher’s exact tests were used, as appropriate. For comparisons of proportions across more than two groups, the Mantel–Haenzel test-for-trend was used. The t-test was used for comparisons of means.

Table 2b. Prevalence of comorbidities among subjects with and without COPD with the LLN criterion.

	Non-COPD n = 1735		COPD LLN n = 104			COPD with FEV1<LLN n = 57
	n	%	n	%	p value	N	%	p value
Myocardial infarction	49	2.8%	6	5.8%	0.125	5	8.8%	0.026
Angina pectoris	42	2.4%	4	3.8%	0.327	3	5.3%	0.170
Coronary artery bypass graft	38	2.2%	1	1.0%	0.722	1	1.8%	1.000
Ischaemic heart disease	82	4.7%	8	7.7%	0.173	6	10.5%	0.057
Heart failure	6	0.3%	4	3.8%	0.002	4	7.0%	<0.001
Arrhythmia	88	5.1%	6	5.8%	0.754	3	5.3%	0.948
Any heart disease	207	11.9%	18	17.3%	0.104	11	19.3%	0.100
Hypertension (or medicines)	433	25.0%	41	39.4%	0.001	27	47.4%	<0.001
Medication for heart disease	290	16.7%	26	25.0%	0.030	18	31.6%	0.003
Medication for heart disease or HT	419	24.1%	36	34.6%	0.016	24	42.1%	0.002
Intermittent claudication	21	1.2%	4	3.8%	0.049	3	5.3%	0.038
TIA or stroke	60	3.5%	5	4.8%	0.412	5	8.8%	0.053
Diabetes	81	4.7%	2	1.9%	0.324	1	1.8%	0.516

HT = Hypertension.

p value = for comparisons against non-COPD. For comparisons of proportions across two groups, the Chi-square or Fisher’s exact tests were used, as appropriate. For comparisons of proportions across more than two groups, the Mantel–Haenzel test-for-trend was used. The t-test was used for comparisons of means.

Table 3. Comorbidities as unadjusted and adjusted relative risks for COPD.

	Dependent variables
	Fixed ratio criterion				LLN criterion
	COPD (all)		Moderate-to-severe COPD		COPD (all)		Moderate-to-severe COPD
Comorbidity (independent variable)	RR	(95% CI)	RR	(95% CI)	RR	(95% CI)	RR	(95% CI)
	Unadjusted analyses
Ischaemic heart disease	1.72	(0.97–3.03)	2.43	(1.16–5.07)	1.62	(0.79–3.33)	2.29	(0.98–5.33)
Heart failure	4.69	(1.74–12.7)	10.8	(3.92–29.5)	7.32	(2.69–19.9)	13.80	(5.00–38.1)
Any heart disease	1.46	(0.96–2.20)	1.73	(0.97–3.10)	1.50	(0.90–2.50)	1.72	(0.89–3.31)
Hypertension (HT)	1.97	(1.44–2.70)	3.60	(2.26–5.73)	1.87	(1.26–2.78)	2.59	(1.54–4.36)
Medication for heart disease or HT	2.03	(1.48–2.78)	3.22	(2.03–5.10)	1.61	(1.08–2.41)	2.21	(1.31–3.74)
Any heart disease. HT or medication	1.85	(1.36–2.53)	2.71	(1.70–4.32)	1.76	(1.19–2.58)	1.84	(1.10–3.10)
Intermittent claudication	2.83	(1.25–6.39)	6.60	(2.86–15.2)	2.90	(1.07–7.88)	4.03	(1.26–12.9)
TIA or stroke	1.44	(0.71–2.92)	2.94	(1.35–6.41)	1.38	(0.56–3.38)	2.62	(1.05–6.57)
Diabetes	1.87	(1.06–3.30)	2.64	(1.27–5.52)	0.41	(0.10–1.68)	0.38	(0.05–2.73)
	Adjusted analyses^a
Ischaemic heart disease	0.79	(0.44–1.43)	0.84	(0.39–1.82)	0.76	(0.36–1.62)	0.84	(0.35–2.03)
Heart failure	2.08	(0.76–5.70)	4.47	(1.58–12.6)	4.52	(1.61–12.7)	7.38	(2.55–21.4)
Any heart disease	0.82	(0.54–1.27)	0.80	(0.44–1.46)	0.92	(0.54–1.57)	0.84	(0.42–1.66)
Hypertension (HT)	1.17	(0.83–1.64)	1.95	(1.18–3.21)	1.32	(0.85–2.04)	1.48	(0.85–2.59)
Medication for heart disease or HT	1.04	(0.74–1.47)	1.46	(0.87–2.44)	0.99	(0.62–1.59)	1.06	(0.59–1.91)
Any heart disease. HT or medication	1.04	(0.74–1.46)	1.32	(0.80–2.20)	1.20	(0.77–1.86)	0.94	(0.53–1.66)
Intermittent claudication	1.21	(0.52–2.81)	2.03	(0.84–4.90)	1.17	(0.42–3.27)	1.21	(0.36–4.01)
TIA or stroke	0.80	(0.39–1.64)	1.30	(0.58–2.90)	0.80	(0.32–2.02)	1.24	(0.48–3.20)
Diabetes	1.13	(0.62–2.07)	1.39	(0.65–2.95)	0.27	(0.07–1.10)	0.20	(0.03–1.44)

^a Analyses are adjusted for sex, age group, pack-years, educational level and exposure to gas, dust or fumes at work.

Comorbidities are added one by one into the model. Grey shading indicates statistical significance.

Figure 2. Comparison between 1994 and 2009–2012 with respect to smoking habits, prevalence of COPD and cardiovascular diseases in COPD. Data from 1994 adapted from reference (15).

Eriksson B, Lindberg A, Müllerova H, Rönmark E, Lundbäck B. Association of heart diseases with COPD and restrictive lung function-results from a population survey. Respir Med. 2013;107(1):98–106.

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