A randomized controlled trial evaluating the effectiveness of a web-based, computer-tailored self-management intervention for people with or at risk for COPD

Figures & data

Figure 1 Consolidated Standards of Reporting Trials diagram.

Abbreviation: GP, general practice.

Table 1 Primary and secondary outcomes

Outcome(s)	Measurement	Scale	Time
Primary
Smoking cessation: 7-day point prevalence abstinence	1 item assessing whether participant smoked during the last 7 daysa	0= did not refrain from smoking during the last 7 days; 1= refrained from smoking during the last 7 days	Follow-up
Level of physical activity	IPAQ-SFb	MET minutes a week (last 7 days): vigorous physical activity =8.0 METs; moderate physical activity =4.0 METs; walking =3.3 METs	Baseline and follow-up
Secondary
Quit attempts	1 item assessing the number of quit attempts during the past 6 monthsa	Number of quit attempts during the past 6 months	Follow-up
24-hour point prevalence abstinence	1 item assessing whether participant smoked during the last 24 hoursa	0= did not refrain from smoking during the last 24 hours; 1= refrained from smoking during the last 24 hours	Follow-up
Continued abstinence	1 item assessing when the last serious quit date was, and 1 item assessing smoking behavior since that datea	0= smoked since the last quit date; 1= did not smoke at all since the last quit date	Follow-up
Prolonged abstinence	1 item assessing when the last serious quit date was, and 1 item assessing smoking behavior since that date, allowing a grace period of 2 weeks in which smoking behavior was not counted as sucha	0= smoked since 2 weeks after the last quit date; 1= did not smoke at all since 2 weeks after the last quit date	Follow-up
Tobacco consumption	4 items assessing what products (cigarettes, rolling tobacco, cigars, or pipe tobacco) are currently smoked, and 4 items assessing how much of each product is currently smokeda	Number of cigarettesf	Baseline and follow-up
Dyspnea status	1 item, MRC scalec	1–5; higher score means worse dyspnea	Baseline and follow-up
Clinical disease control	10-item CCQd	0= very good control; 6= extremely poor control	Baseline and follow-up
Intention to quit smoking	1 item, 7-point Likert scalee	1= I certainly plan to quit smoking; 7= I certainly do not plan to quit smoking	Baseline and follow-up
Intention to increase the level of physical activity	1 item, 7-point Likert scalee	1= I certainly plan to be more physically active; 7= I certainly do not plan to be more physically active	Baseline and follow-up

Notes:

a Smoking cessation questions were selected based on the Russel Standard³³ and a Dutch guide published by Stivoro that aimed to standardize smoking cessation measures in the Netherlands.³⁴ Self-report has been shown to be reliable in COPD patients: kappa coefficient =0.20 for biochemical validation at 6-month measurement, P=0.003.⁶¹

b The reliability and validity of the IPAQ-SF have been tested in the Dutch population: test–retest reliability, ρ=0.85; concurrent validity between long and short IPAQ, from ρ=0.85 to 0.88; criterion validity against accelerometer, ρ=0.32.³⁵

c The MRC scale is a useful measure for disability. Significant associations were found between disability MRC grade and shuttle distance, St George Respiratory Questionnaire,⁶² Chronic Respiratory Questionnaire⁶³ scores, mood state, and Nottingham Extended Activities of Daily Living⁶⁴ scores. Forced expiratory volume in one second was not associated with MRC grade.³⁶

d The CCQ is validated in the Dutch population and can be used for COPD patients and individuals at risk for COPD: Cronbach’s alpha =0.91(internal consistency), significantly higher score of people with or at risk for COPD compared to healthy (ex-)smokers (P<0.05) (discriminate validity), significant correlations with 36-Item Short Form Health Survey (ρ=0.48–0.69)⁶⁵ and St George Respiratory Questionnaire (ρ=0.67–0.72) (internal consistency); correlation with forced expiratory volume in one second % predicted ρ=–0.49 (divergent validity); intra class coefficient =0.94 (test–retest reliability); significant improvement in CCQ found after 2 months’ smoking cessation (responsiveness).³⁷

e The intention questions were based on the I-Change model.^29,30 The “intention to quit smoking” question has previously been used successfully in a similar intervention study.⁶⁶

f The overall score for tobacco consumption was expressed as the number of cigarettes, whereby one hand-rolled cigarette equaled one commercial cigarette, and one cigar equaled four cigarettes.³⁴ We considered one pipe to equal one cigarette, since no concrete guidelines were available on converting the number of pipes to cigarettes.

Abbreviations: CCQ, Clinical COPD Questionnaire; IPAQ-SF, International Physical Activity Questionnaire – Short Form; MET, metabolic equivalent task; MRC, Medical Research Council.

Table 2 Baseline characteristics of study participants – overall, experimental and control group

Characteristic	Overall sample (n=1,307)	Experimental group (n=658)	Control group (n=649)
Age, years (mean [SD])	57.6 (7.2)	57.7 (7.3)	57.6 (7.2)
Male (n [%])	627 (48.0)	326 (49.5)	301 (46.4)
Education level (n [%])
Primary school/basic vocational school	386 (29.5)	191 (29.0)	195 (30.0)
Secondary vocational school/high school degree	427 (32.7)	209 (31.8)	218 (33.6)
Higher professional degree/university degree	494 (37.8)	258 (39.2)	236 (36.4)
Current employment status (n [%])
Employed	670 (51.3)	356 (54.1)	314 (48.4)
Not employed	637 (48.7)	302 (45.9)	335 (51.6)*
Marital status (n [%])
Single/divorced/widowed	348 (26.6)	171 (26.0)	177 (27.3)
In a relationship/living together/married	959 (73.4)	487 (74.0)	472 (72.7)
COPD status (n [%])
Diagnosed with COPD	284 (21.7)	146 (22.2)	138 (21.3)
Increased risk for COPD per RHSQ^Citation19	1,023 (78.3)	512 (77.8)	511 (78.7)
Comorbidity (n [%])
≥1 chronic condition	604 (46.2)	292 (44.4)	312 (48.1)
Respiratory disease	224 (17.1)	106 (16.1)	118 (18.2)
Cancer	53 (4.1)	30 (4.6)	23 (3.5)
Diabetes	120 (9.2)	57 (8.7)	63 (9.7)
Cardiovascular disease	200 (15.3)	98 (14.9)	102 (15.7)
Musculoskeletal disorder	90 (6.9)	41 (6.2)	49 (7.6)
Other chronic condition	124 (9.5)	58 (8.8)	66 (10.2)
MRC dyspnea^Citation36 (n=1,305)
No breathlessness	359 (27.5)	177 (26.9)	182 (28.1)
1	523 (40.1)	264 (40.2)	259 (40.0)
2	318 (24.4)	167 (25.4)	151 (23.3)
3	75 (5.7)	34 (5.2)	41 (6.3)
4	19 (1.5)	9 (1.4)	10 (1.5)
5	11 (0.8)	6 (0.9)	5 (0.8)
Smoking status
Currently smoking	447 (34.2)	241 (36.6)	206 (31.7)
Currently not smoking	860 (65.8)	417 (63.4)	443 (68.3)
Number of cigarettes smoked/day among smokers, n=447 (mean [SD])	19.3 (12.1)	19.0 (12.3)	19.8 (11.9)
FTND score (range 0–10)^Citation38 among smokers, n=447 (mean [SD])	4.2 (2.3)	4.1 (2.3)	4.4 (2.3)
Number of previous quit attempts among smokers, n=447 (mean [SD])	3.8 (8.8)	3.1 (4.0)	4.8 (12.2)
Intention to quit smoking (range 1–7) among smokers, n=447 (mean [SD])	3.7 (1.9)	3.7 (2.0)	3.7 (1.9)
Level of physical activity (MET per week), n=1,096 (mean [SD])	4,012.6 (3,933.3)	4,108.7 (4,034.0)	3,914.1 (3,828.4)
Intention to be more physically active (range 1–7) (mean [SD])	3.2 (1.7)	3.2 (1.7)	3.1 (1.7)
CCQ score (range 0–6)^Citation37 (mean [SD])	1.0 (0.9)	1.0 (0.9)	1.0 (0.8)

Note:

* P<0.05.

Abbreviations: CCQ, Clinical COPD Questionnaire; FTND, Fagerström Test for Nicotine Dependence; MET, metabolic equivalent task; MRC, Medical Research Council; RHSQ, Respiratory Health Screening Questionnaire; SD, standard deviation.

Table 3 Number of participants (%) who completed intervention components of the physical activity and smoking cessation modules

Module	Number of components completed
	0	1	2	≥3
Physical activity	465 (70.7)	107 (16.3)	48 (7.3)	38 (5.8)
Smoking cessation, among smokers	190 (78.8)	29 (12.0)	12 (5.0)	10 (4.1)

Table 4 Effects of the web-based COPD self-management intervention on all primary and secondary outcomes

Primary and secondary outcomes	Uncorrected effects	Corrected effects
7-day point prevalence abstinencea	OR=1.12, (0.45; 2.77*), P=0.810	OR=1.06, (0.43; 2.66), P=0.895
MET minutes a weekb	b=−64.70, (−455.39; 326.00), P=0.745	b=−84.33, (−476.39; 307.74), P=0.673
24-hour point prevalence abstinencea	OR=0.77, (0.36; 1.67), P=0.510	OR=0.72, (0.33; 1.59), P=0.420
Prolonged abstinencea	OR=0.90, (0.35; 2.34), P=0.834	OR=0.86, (0.33; 2.25), P=0.766
Continued abstinencea	OR=1.02, (0.39; 2.72), P=0.963	OR=0.98, (0.37; 2.63), P=0.969
Number of cigarettesc	b=−0.08, (−1.82; 1.65), P=0.925	b=0.11, (−1.61; 1.84), P=0.899
Intention to quit smokingd	b=−0.01, (−0.31; 0.28), P=0.937	b=−0.03, (−0.32; 0.26), P=0.826
Number of quit attemptse	b=−0.36, (−1.10; 0.37), P=0.334	b=−0.38, (−1.11; 0.36), P=0.312
Intention to increase physical activityf	b=0.00, (−0.17; 0.17), P=0.991	b=0.00, (−0.17; 0.17), P=0.987
Clinical disease controlg	b=−0.06, (−0.11; −0.01), P=0.010	b=−0.03, (−0.07; 0.01), P=0.134
Dyspnea statush	OR=1.16, (0.89; 1.51), P=0.283	OR=1.28, (0.92; 1.79), P=0.149

Notes:

* 95% confidence intervals are shown within brackets.

a Logistic regression analyses were performed. The corrected analysis only included intention to quit smoking, as including more variables would have overloaded the model. The number of smokers in the general practice group followed up was too small (n=4) to yield reliable results when including recruitment channel in the model.

b Linear mixed-model analyses were performed, corrected for age, sex, recruitment channel, smoking status, employment status, comorbidity (yes/no), MRC score, and intention to increase physical activity.

c Linear mixed-model analyses were performed, corrected for age, sex, marital status, CCQ score, level of education, MRC score, and FTND score.

d Linear mixed-model analyses were performed, corrected for age, sex, level of education, CCQ score, MRC score, number of quit attempts, and employment status.

e Linear regression analyses were performed, corrected for age, sex, level of education, CCQ score, MRC score, and FTND score.

f Linear mixed-model analyses were performed, corrected for age, sex, recruitment channel, smoking status, employment status, and MRC score.

g Linear mixed-model analyses were performed, corrected for age, sex, recruitment channel, smoking status, employment status, COPD status, comorbidity (yes/no), marital status, level of physical activity, MRC score, and level of education.

h Logistic regression analyses were performed, corrected for age, sex, recruitment channel, smoking status, employment status, COPD status, comorbidity (yes/no), marital status, level of physical activity, CCQ score, and level of education. Dyspnea status was recoded (0= participants who experienced a form of breathlessness and scored 1–5 on the MRC dyspnea score; 1= participants who indicated to have no breathlessness).

Abbreviations: b, estimated mean difference; CCQ, Clinical COPD Questionnaire; FTND, Fagerström Test for Nicotine Dependence; MET, metabolic equivalent task; MRC, Medical Research Council; OR, odds ratio.

Table 5 Corrected effects of the per protocol analyses for primary outcomes

Primary outcomes	At least 1 component completed	At least 2 components completed	At least 3 components completed
7-day point prevalence abstinencea	OR=1.75, (0.51; 6.00), P=0.371	OR=3.57, (0.87; 14.73), P=0.078	No reliable resultsc
MET minutes a weekb	b=−101.58, (−653.10; 449.94), P=0.718	b=120.92, (−683.86; 925.71), P=0.768	b=813.44, (−383.29; 2,010.17), P=0.182

Notes: 95% confidence interval between brackets.

a Logistic regression analyses were performed. This analysis did not include covariates due to the small number of events (successful behavior changes).

b Linear mixed-model analyses were performed, corrected for age, sex, recruitment channel, smoking status, employment status, comorbidity (yes/no), MRC score, intention to increase physical activity;

c no events (successful behavior change) in the experimental group.

Abbreviations: b, estimated mean difference; MET, metabolic equivalent task; OR, odds ratio.

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