Influences of patient education on exacerbations and hospital admissions in patients with COPD – a longitudinal national register study

Figures & data

Table 1. Labels for the categorical steps in mMRC.

Numeric value	Labels
0	I only get breathless with strenuous exercise.
1	I get short of breath when hurrying on level ground or walking up a slight hill.
2	On level ground, I walk slower than people of the same age because of breathlessness or have to stop for breath when walking at my own pace.
3	I stop for breath after walking about 100 yards or after a few minutes on level ground.
4	I am too breathless to leave the house or I am breathless when dressing.

Table 2. Differences between patients at baseline and at follow-up at a visit at 10–30 months later.

	All patients (n = 20,666)	Patients who participated in follow-up (n = 3,497)
	At baseline	Baseline	Follow-up after 10–30 months	Change between baseline and follow-up
	Mean (SD)	Mean (SD)	Mean (SD)	Mean (SD)
Demographic variables	n (%)	n (%)	n (%)	n (%)	p-Value for change
Age	69.3 (9.7)	68.7 (8.8)	70.1 (8.8)	1.4 (0.6)
Sex
Men	9,126 (44.2%)	1,612 (46.1%)
Women	11,540 (55.8%)	1,885 (53.9%)
Social situation
Living alone	1,930 (38.6%)	600 (35.6%)
Cohabiting	3,072 (61.4%)	1,086 (64.4%)
Clinical variables
Stage of COPD					0.025
I: (80–100% of predicted FEV1)	8.2%	5.3%	6.1%	Improved: 328 (11.6%)
II: (50–79% of predicted FEV1)	50.2%	48.4%	47.3%	Unchanged: 2,121 (74.7%)
III: (30–49% of predicted FEV1)	31.9%	36.5%	34.7%	Deteriorated: 389 (13.7%)
IV: (0–29% of predicted FEV1)	9.0%	9.7%	11.8%
FEV1% of predicted value	51.7 (19.2)	50.0 (16.7)	50.2 (17.8)	0.22 (10.9)	0.27
Saturation	95.6 (2.6)	95.7 (2.3)	95.7 (2.4)	0.03 (2.1)	0.47
Exacerbations during the last 12 months	0.72 (1.3)	0.73 (1.3)	0.73 (1.4)	−0.00 (1.4)	0.88
Hospital admissions the last 12 months	0.25 (0.8)	0.17 (0.6)	0.18 (0.7)	0.00 (0.8)	0.80
Body mass index (BMI)	26.4 (6.9)	26.6 (7.3)	26.6 (9.5)	0.02 (9.4)	0.91
Patient-reported variables
Exercise capacity, days per week	3.2 (2.8)	3.6 (2.8)	3.6 (2.8)	−0.09 (2.7)	0.091
Quality of life according to CCQ	1.84 (1.17) (n = 5,399)	1.69 (1.08) (n = 1,163)	1.79 (1.15)	0.10 (0.89)	<0.001
Functional dyspnea (mMRC)	1.86 (1.24)	1.81 (1.18)	1.93 (1.24)	0.13 (1.00)	<0.001
Functional dyspnea (mMRC) categorical					<0.001
0	1,384 (11.4%)	284 (10.2%)	271 (9.2%)	Improved: 542 (20.8%)
1	4,462 (36.6%)	1,081 (38.9%)	1,088 (36.9%)	Unchanged: 1,293 (49.6%)
2	2,593 (21.3%)	636 (22.9%)	637 (21.6%)	Deteriorated: 772 (29.6%)
3	2,010 (16.5%)	448 (16.1%)	480 (16.3%)
4	1,732 (14.2%)	332 (11.9%)	476 (16.1%)

Paired sample t-test for continuous variables and Sign test for categorical variables.

Table 3. Differences between participants and non-participants in patient education programs.

	Patients who did not participate in patient education at baseline (n = 7,377)
	Patients who did not participate in patient education at follow-up (n = 1,185)				Patients who did participate in patient education at follow-up (n = 494)				Comparisons between participants and non-participants
Demographic variables	Baseline	Follow-up	Change from baseline to follow-up	p-Value for change	Baseline	Follow-up	Change from baseline to follow-up	p-Value for change	p-Value between baseline of participants and non-participants	p-Value between follow-up of participants and non-participants	Change and p-value for comparison of change
Age, mean (SD)	68.4 (9.2)	69.8 (9.2)			68.77 (8.6)	70.2 (8.6)			0.47
Sex n (%)									0.89
Men	569 (48%)				239 (48.4%)
Women	616 (52%)				255 (51.6%)
Social situation n (%)									0.37
Living alone	263 (34.4%)				119 (37.3%)
Cohabiting	501 (65.6%)				200 (62.0%)
	Mean (SD)	Mean (SD)	Mean (SD)		Mean (SD)	Mean (SD)
Clinical variables
FEV1% of predicted value	50.7 (16.0)	50.8 (16.9)	0.31 (9.3)	0.27	49.9 (16.6)	49.8 (17.4)	0.70 (10.6)	0.15	0.41	0.29	−0.39, p = 0.46
Exacerbations during the last 12 months	0.7 (1.2)	0.7 (1.3)	0.03 (1.4)	0.56	0.8 (1.4)	0.8 (1.4)	0.01 (1.6)	0.88	0.42	0.14	0.007, p = 0.87
Hospital admissions the last 12 months	0.3 (0.7)	0.2 (0.6)	0.01 (0.70)	0.74	0.3 (0.9)	0.2 (0.9)	−0.01 (1.1)	0.85	0.86	0.4	0.0, p = 0.84
	Mean (SD)	Mean (SD)	Mean (SD)		Mean (SD)	Mean (SD)	Mean (SD)
Patient-reported variables
Exercise capacity, days per week	3.9 (2.8)	3.6 (2.8)	−0.08 (2.7)	0.38	3.5 (2.8)	3.4 (2.7)	−0.05 (0.9)	0.70	0.95	0.17	−0.13, p = 0.87
Quality of life according to CCQ	1.58 (1.03) (n = 867)	1.72 (1.14) (n = 733)	0.13 (0.87) (n = 654)	<0.001	1.77 (1.10) (n = 380)	1.68 (1.13) (n = 209)	−0.05 (0.91) (n = 187)	0.50	<0.001	0.62	0.08, p = 0.016^b
Functional dyspnea (mMRC)	1.71 (1.16)	1.89 (1.22)	0.16 (1.01)	<0.001	1.92 (1.20)	2.0 (1.25)	0.08 (1.01)	0.081	0.002	0.093	0.08, p = 0.14
	n (%)	n (%)	n (%)		n (%)	n (%)	n (%)
Functional dyspnea (mMRC) categorical^a				<0.001
0	125 (11.3%)	107 (9.5%)	Improved: 205 (19.4%)		37 (7.7%)	40 (8.5%)	Improved: 104 (22.6%)
1	461 (41.8%)	431 (38.3%)	Unchanged: 530 (50.0%)		183 (38.3%)	162 (34.4%)	Unchanged: 232 (50.4%)
2	239 (21.7%)	237 (21.1%)	Deteriorated: 324 (30.6%)		111 (23.2%)	111 (23.6%)	Deteriorated: 124 (27.0%)
3	164 (14.9%)	183 (16.3%)			76 (15.9%)	74 (15.7%)
4	114 (10.3%)	167 (14.8%)			71 (14.9%)	84 (17.8%)

Within the samples, for comparison overtime, paired sample t-tests were used for continuous variables and the Sign test for categorical variables. For differences between the samples of patients who participated in patient education at follow-up and patients who did not, the independent sample t-test was used for continuous variables and the Mantel–Haenszel chi-square test for ordered categorical variables.

^a For category labels, see Table 1.

^b Due to differences in baseline values an ANOVA was performed, p = 0.733.

Table 4. Differences between participants and non-participants in smoking cessation program.

	Patients who did not participate in smoking cessation program at baseline (n = 4,768)
	Patients who did not participate at follow-up (n = 747)				Patients who did participate at follow-up (n = 154)				Comparisons between participants and non-participants
Demographic variables	Baseline	Follow-up	Change between baseline and follow-up	p-Value for change	Baseline	Follow-up	Change between baseline and follow-up	p-Value for change	p-Value between baseline of participants and non-participants	p-Value between follow-up of participants and non-participants	p-Value for comparison of change
Age, mean (SD)	68.1 (8.8)				66.0 (7.8)				0.006
Sex, n (%)									0.077
Men	364 (48.7)				63 (40.9%)
Women	383 (51.3%)				91 (59.1%)
Social situation, n (%)									0.30
Living alone	160 (33.7%)				41 (39.0%)
Cohabiting	315 (66.3%)				64 (61.0%)
	Mean (SD)	Mean (SD)	Mean (SD)		Mean (SD)	Mean (SD)
Clinical variables
FEV1% of predicted value	50.8 (16.0)	50.6 (17.0)	−0.15 (9.1)	0.59	51.1 (17.2)	51.1 (17.5)	0.04 (11.5)	0.97	0.80	0.10	0.82
Exacerbations during the last 12 months	0.8 (1.3)	0.8 (1.5)	0.06 (1.4)	0.26	0.8 (1.2)	0.6 (1.0)	−0.2 (1.3)	0.17	0.79	0.17	0.09
Hospital admissions the last 12 months	0.2 (0.7)	0.2 (0.8)	−0.03 (0.8)	0.28	0.2 (0.7)	0.1 (0.4)	−0.02 (0.4)	0.74	0.73	0.16	0.50
	n (%)	n (%)	n (%)		n (%)	n (%)
Prescription of smoking cessation medication	26 (4.0%)	12 (2.0%)	Increased: 21 (3.6%) Unchanged: 487 (84.4%) Decrease: 48 (8.3%)	<0.001	15 (12.0%)	33 (30.3%)	Increased: 4 (4.1%) Unchanged: 57 (58.1%) Decrease: 31 (31.6%)	0.45	0.001	0.001	0.193
	Mean (SD)	Mean (SD)	Mean (SD)		Mean (SD)	Mean (SD)
Patient-reported variables
Exercise capacity, days per week	3.6 (2.8)	3.3 (2.8)	−0.2 (2.7)	0.387	3.6 (2.9)	3.8 (2.7)	0.3 (2.4)	0.18	0.76	0.32	0.045
Quality of life according to CCQ	1.75 (1.11) (n = 571)	1.87 (1.16) (n = 505)	0.09 (0.80) (n = 461)	0.007	1.49 (1.05) (n = 113)	1.68 (1.24) (n = 82)	0.06 (0.87) (n = 77)	0.55	0.020	0.81	0.77
Functional dyspnea (mMRC)	1.74 (1.22)	1.97 (1.27)	0.21 (1.00)	<0.001	1.77 (1.15)	1.79 (1.16)	0.04 (0.98)	0.60	0.80	0.95	0.067
	n (%)	n (%)	n (%)		n (%)	n (%)	n (%)
Functional dyspnea (mMRC) categorical^a				<0.001				1.0	0.80	0.10	0.054
0	83 (11.7%)	61 (8.5%)	Improved: 18.1%		14 (9.9%)	16 (10.8%)	Improved: 27.3%
1	295 (41.7%)	270 (37.8%)	Unchanged: 50.5%		56 (39.7%)	53 (35.8%)	Unchanged: 44.6%
2	139 (19.7%)	144 (20.1%)	Deteriorated: 31.4%		34 (24.1%)	42 (28.4%)	Deteriorated: 28.1%
3	99 (14.0%)	107 (15.0%)			22 (16.6%)	20 (13.5%)
4	91 (12.9%)	133 (18.6%)			15 (10.6%)	17 (11.5%)

Within samples, paired sample t-tests were uses for continuous variables and Sign test for categorical variables. For differences between patients who participated in a smoking cessation program at follow-up and patients who did not, independent sample t-test was used for continuous variables and Mantel–Haenszel chi-square test for ordered categorical variables.

^aFor category labels, see Table 1.

Figure 1. Flowchart over participants and non-participants in patient education.

Figure 2. Flowchart for participants and non-participants in a smoking cessation program.

Table 5. Smoking among the patients who participated and not participated in patient education and smoking cessation program.

Smoking	All patients (n = 20,666) at baseline
Non-smoker	1,966 (11.4%)
Have quit smoking	9,349 (54.1%)
Still smoking	5,976 (34.6%)
	Patients who participated in follow-up (n = 3,497)
	Baseline	Follow-up after 10–30 months	Change between baseline and follow-up	p-Value for change
Non-smoker	223 (6.9%)	234 (6.9%)	Incr smok: 3.5%	<0.001
Have quit smoking	1,923 (59.5%)	2,112 (62.5%)	Unch smok: 89.0%
Still smoking	1,088 (33.6%)	1,035 (30.6%)	Decr smok: 7.5%
	Patients who did not participate in patient education at follow-up (n = 1,185)				Patients who did participate in patient education at follow-up (n = 494)				Comparison between participants and non-participants
	Baseline	Follow-up	Change between baseline and follow-up	p-Value for change	Baseline	Follow-up	Change from baseline to follow-up	p-Value for change	p-Value baseline	p-Value follow-up	p-Value for change
Non-smoker	31 (2.6%)	32 (2.7%)	Incr smok: 3.5%	<0.001	15 (3.0%)	17 (3.5%)	Incr smok: 4.9%	0.030	0.002	0.002	0.28
Have quit smoking	707 (59.8%)	754 (63.7%)	Unch smok: 89.0%		332 (67.5%)	345 (70.7%)	Unch smok: 86.6%
Still smoking	445 (37.6%)	398 (33.6%)	Decr smok: 7.5%		145 (29.5%)	126 (25.8%)	Decr smok: 8.4%
	Patients who did not participate in smoking cessation program at follow-up (n = 747)				Patients who did participate in smoking cessation program at follow-up (n = 154)				Comparison between participants and non-participants
	Baseline	Follow-up	Change between baseline and follow-up	p-Value for change	Baseline	Follow-up	Change from baseline to follow-up	p-Value for change	p-Value baseline	p-Value follow-up	p-Value for change
Non-smoker	0	0	Incr smok: 3.2%	0.42	0	0	Incr smok: 5.8%	0.010	<0.001	<0.001	<0.001
Have quit smoking	369 (49.4%)	376 (50.3%)	Unch smok: 92.6%		36 (23.4%)	52 (33.8%)	Unch smok: 77.9%
Still smoking	378 (50.6%)	371 (49.7%)	Decr smok: 4.1%		118 (76.6%)	102 (66.2%)	Decr smok: 16.2%

For comparisons between baseline and follow-up in categorical variables Sign test was used. For comparisons between participants and non-participants Mantel–Haenszel chi-square test for ordered categorical variables. Incr smok = increased smoking; unch smok = unchanged smoking; Decr smok = decreased smoking.

Table 6. Logistic regression with patient education program and smoking cessation programs as dependent variables. Patients were included if they had not participated in the intervention at baseline. The independent variables are from baseline.

	Participation in patient education program		Participation in smoking cessation program
	Univariable	Multivariable	Univariable	Multivariable
Independent variables	OR (95% CI) p	OR (95% CI) p	OR (95% CI) p	OR (95% CI) p
Constant		0.456		0.70
Age, divided by 10 years	1.04 (0.93, 1.17) 0.47		0.76 (0.62, 0.93) 0.006	0.76 (0.62, 0.93) 0.006
Gender (1 = man, 2 = woman)	0.99 (0.80, 1.22) 0.89		1.37 (0.97, 1.95) 0.078
Social situation (0 = living alone; 1 = cohabiting)	0.88 (0.67, 1.16) 0.37		0.79 (0.51, 1.23) 0.30
FEV1% of predicted value	0.99 (0.99, 1.00) 0.045		1.00 (0.99, 1.01) 0.80
Exacerbations the last 12 months	1.10 (1.02, 1.19) 0.020	1.11 (1.02, 1.21) 0.015	1.02 (0.89, 1.16) 0.79
Hospital admissions due to COPD the last 12 months	1.14 (0.95, 1.35) 0.16		0.94 (0.65, 1.36) 0.73
Smoking, dichotomized	0.69 (0.55, 0.87) 0.002	0.69 (0.52, 0.85) 0.001
Dyspne_mMRC.0	1		1
Dyspne_mMRC.0 [1]	1.34 (0.90, 2.01) 0.155		1.02 (0.47, 2.25) 0.95
Dyspne_mMRC.0 [2]	1.57 (1.02, 2.41) 0.040		1.15 (0.62, 2.13) 0.65
Dyspne_mMRC.0 [3]	1.57 (0.99, 2.47) 0.054		1.48 (0.77, 2.88) 0.24
Dyspne_mMRC.0 [4]	2.10 (1.31, 3.37) 0.002		1.35 (0.66, 2.76) 0.41

Multivariable stepwise logistic regression.

Table 7. Generalized linear models with negative binomial distribution analysis with number of exacerbations and hospital admissions as dependent variables, and with independent variables from baseline.

	Number of exacerbations at follow-up after >1 year		Number of Hospital admissions at follow-up after >1 year
	Univariable	Multivariable	Univariable	Multivariable
Independent variables at baseline	RR (95% CI) p	RR (95% CI) p	RR (95% CI) p	RR (95% CI) p
Intercept		2.23 (0.92, 5.43) 0.076		0.18 (0.04, 0.83) 0.028
Age, divided by 10 years	0.99 (0.89, 1.10) 0.045		1.24 (1.10, 1.41) 0.001
Sex (1 = man, 2 = woman)	0.82 (0.72, 0.92) 0.001		0.84 (0.67, 1.04) 0.106
Social situation (0 = living alone; 1 = cohabiting)	0.88 (0.74, 1.03) 0.119		1.43 (1.10, 1.86) 0.007
FEV1% of predicted value	0.97 (0.97, 0.98) <0.001	0.98 (0.97, 0.98) <0.001	0.95 (0.94, 0.96) <0.001	0.96 (0.95, 0.97) <0.001
Exacerbations the last 12 months	1.49 (1.42, 1.56) <0.001	1.42 (1.31, 1.54) <0.001	1.45 (1.36, 1.54) <0.001	1.23 (1.12, 1.36) <0.001
Hospital admissions due to COPD the last 12 months	1.59 (1.43, 1.77) <0.001		2.12 (1.86, 2.42) <0.001
Smoking, dichotomized	1.31 (1.15, 1.49) <0.001		1.58 (1.23, 2.02) <0.001
Participation in patient education program	0.89 (0.77, 1.01) 0.079		1.01 (0.78, 1.30) 0.93
Participation in smoking cessation program	1.07 (0.91, 1.26) 0.40		1.30 (0.96, 1.75) 0.087

Generalized linear models with negative binomial distribution analysis. RR= risk ratio

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