Co-morbidity in Mild-to-Moderate COPD: Comparison to Normal and Restrictive Lung Function

Figures & data

Table 1  Study population, basic characteristics by lung function (lf), gender, age, BMI and smoking habits

	Non-COPD	COPD	p^1	Normal lf	Restrictive lf	p^2	p^3	p^4
N (%)	993	993		776 (78.1)	217 (21.9)
GOLD I, n (%)		556 (56.0)
GOLD II		373 (37.6)
GOLD III-IV		64 (6.4)
Gender, n (%)
Men	540 (54.3)	544 (54.8)		383 (49.4)	157 (72.4)
Women	453 (45.6)	449 (45.2)	0.857	393 (50.6)	60 (27.6)	<0.001
Age, mean	64.3	64.8	0.332	62.8	69.7	<0.001	<0.001^5	<0.001^5
BMI, mean	26.58	26.06	0.003	26.48	26.95	0.113	0.027	0.004^5
Smoking habits, n (%)
Non-smoker	474 (47.7)	239 (24.2)		373 (48.1)	101 (46.5)
Ex-smoker	394 (39.7)	419 (42.4)		293 (37.8)	101 (46.5)
Current smoker	125 (12.6)	331 (33.5)	<0.001	110 (14.2)	15 (6.9)	0.005

¹p-value comparing non-COPD and COPD.

² p-value comparing normal and restrictive lung function in non-COPD.

³p-value comparing normal lung function and COPD.

⁴p-value comparing restrictive lung function and COPD.

⁵After Bonferroni correction (p³, p⁴).

Table 2  Respiratory symptoms and co-morbidity in normal compared to restrictive lung function, in non-COPD compared to COPD, and by disease severity divided into GOLD stage I and ≥stage II, and in COPD compared to normal and also restrictive lung function

	Normal	Restrictive	p^1	Non-COPD	COPD	p^2	COPD StageI	p^3	COPD Stage≥II	p^3	p^4	p^5
Long-standing cough	20.1	24.9	0.130	21.2	32.4	<0.001	26.5	0.017^2	39.9	<0.001^6	<0.001^7	0.039^7
Need to clear the throat	49.5	57.6	0.034	51.3	69.9	<0.001	66.3	<0.001^2	74.6	<0.001^6	<0.001^7	<0.001^7
Bronchitis	21.3	34.9	<0.001	23.9	43.8	<0.001	39.1	<0.001^2	49.6	<0.001^6	<0.001^7	0.005^7
Recurrent wheeze	16.5	26.9	0.001	18.8	49.7	<0.001	38.5	<0.001^2	64.0	<0.001^6	<0.001^7	<0.001^7
Chronic rhinitis	32.3	41.0	0.017	34.2	43.1	<0.001	41.0	0.008^2	45.8	<0.001^6	<0.001^7	0.573
Heart disease	13.7	24.4	<0.001	16.0	18.5	0.138	15.6	0.851	22.2	0.005^6	0.006^7	0.047
Stroke	6.4	9.5	0.159	7.1	7.7	0.624	7.8	0.647	7.7	0.729	0.333	0.425
Hypertension	33.9	46.1	0.001	36.6	39.6	0.171	37.9	0.596	41.6	0.070	0.015^7	0.077
Claudication	2.0	8.3	<0.001	3.4	7.0	0.001	5.6	0.052	8.7	<0.001^6	<0.001^7	0.521
CVD**	41.0	59.0	<0.001	44.9	50.1	0.022	47.7	0.298	53.1	0.004^6	<0.001^7	0.017^7
Hyperlipemia	12.9	19.2	0.033	14.3	14.8	0.786	15.0	0.746	14.6	0.914	0.301	0.132
Diabetes	8.6	20.9	<0.001	11.3	10.0	0.392	9.0	0.174	11.4	0.964	0.335	<0.001^7
GERD***	12.0	16.0	0.165	12.9	16.7	0.027	15.1	0.262	18.8	0.007^6	0.011^7	0.819

¹p-value when comparing normal lung function and restrictive lung function.

²p-value when comparing non-COPD to COPD.

³p-value when comparing COPD stage I and stage ≥II to non-COPD.

⁴p-value when comparing COPD and normal lung function.

⁵p-value when comparing COPD and restrictive lung function.

^6,7significant also after Bonferroni correction when comparing COPD stage I and stage ≥II to non-COPD and COPD to normal and restrictive lung function, respectively.

*Intermittent claudication.

**Cardiovascular disease.

***Gastroesophageal reflux.

Figure 1  Symptoms and diseases in subjects with normal lung function (Nlf) and in subjects with COPD, by disease severity (divided into stage I and stage ≥II), in percent.

Figure 2  (a). Prevalence of and overlap between heart disease, chronic rhinitis and gastroesophageal reflux (GERD) in subjects with COPD (presented as percentage of all subjects with COPD, n = 993). (b). Prevalence of and overlap between heart disease, chronic rhinitis and gastroesophageal reflux (GERD) in subjects with normal lung function (presented as percentage of all subjects with normal lungfunction, n = 776).

Table 3  Comparing respiratory symptoms and co-morbidity by gender in non-COPD and in COPD, respectively

	Non-COPD			COPD
	Men	Women	p^1	Men	Women	p^1
Chronic rhinitis	34.8	33.6	0.691	41.2	45.4	0.178
Heart disease	18.3	13.2	0.029	23.2	12.9	<0.001
Stroke	9.2	4.6	0.010	8.5	6.7	0.304
Hypertension	34.6	38.9	0.161	36.4	43.4	0.024
Claudication	2.9	4.0	0.377	7.0	7.0	0.993
CVD**	45.0	44.8	0.953	49.8	50.3	0.871
Hyperlipemia	17.9	10.1	0.002	16.7	12.5	0.070
Diabetes	13.2	9.1	0.064	12.3	7.2	0.011
GERD***	12.7	13.1	0.882	14.9	18.8	0.113

¹Comparing men and women.

²Heart disease or hypertension or stroke or claudication.

*Intermittent claudication.

**Cardiovascular disease.

***Gastroesophageal reflux.

Table 4  COPD stage I, COPD stage ≥II and restricted lung function analysed as risk factors for heart disease, hypertension, intermittent claudication (claudication), stroke, cardiovascular disease (CVD), diabetes, GERD and chronic rhinitis in a multivariate model adjusting for the co-variates gender, BMI, smoking habits and age presented as odds ratio, OR (95% confidence interval, CI)

Lung function	Heart disease^1	Hypertension^2	Claudication^0	Stroke^1	**CVD^0	Diabetes^1	***GERD^0	Chronic rhinitis^0
Normal	1	1	1	1	1	1	1	1
COPD stage I	0.89 (0.64–1.25)	1.26 (0.99–1.61)	2.21 (1.11–4.40)	0.91 (0.56–1.48)	1.25 (0.98–1.59)	1.03 (0.67–1.58)	1.19 (0.83–1.69)	1.37 (1.09–1.74)
COPD stage≥II	1.52 (1.08–2.14)	1.41 (1.08–1.61)	3.51 (1.77–6.97)	1.05 (0.63–1.77)	1.56 (1.19–2.03)	1.32 (0.85–2.05)	1.43 (0.99–2.06)	1.73 (1.34–2.23)
Restricted	1.08 (0.72–1.62)	1.36 (0.98–1.89)	2.86 (1.29–6.31)	0.87 (0.47–1.63)	1.42 (1.02–1.97)	1.84 (1.14–2.97)	1.35 (0.83–2.20)	1.38 (1.00–1.90)

¹Increased risk in men.

²Increased risk in women.

⁰No significant gender difference.

*Intermittent claudication.

**Cardiovascular disease.

***Gastroesophageal reflux.