The impact of repeated spirometry and smoking cessation advice on smokers with mild COPD

Figures & data

Figure 1.  Trial design showing excluded and annual follow-up rates. Twelve of the smokers with normal lung function (NLF) (group B) and 13 of the smokers with COPD did not wish to be followed up at all. A number of smokers dropped out because of moving to another city or had died. *Smokers not present at this particular visit.

Table I.  Baseline characteristics showing gender, mean age, number of pack-years, cigarettes/day, and lung function by study group.

	Group A n = 165	Group B n = 161	Group C n = 119
Age	47.6	47.6	49.27
Gender Male	74 (45%)	67 (42%)	53 (45%)
Female	91 (55%)	94 (58%)	66 (55%)
Pack-years	24 (SD 12)	24 (SD 10)	32 (SD 13)
Cigarettes/day	16 (SD 6)	16 (SD 6)	19 (SD 8)
FEV1% predicted (mean)	98	95	77
Excluded	20 (12%)	16 (10%)	18 (15%)
Participants	164 (99%)	145 (90%)	101 (85%)

Group A and group B consist of smokers with normal lung function and group C consists of smokers with COPD. Standard deviation and percentages within parentheses.

Table II.  Data on subjects who stopped smoking at the annual visit by study group.

Follow-up	Group A n = 165	Group B n = 161			Group C n = 119			Group B versus Group C
Year	3	1	2	3	1	2	3	Year 3
n = present at annual visit	n = 144	n = 140	n = 138	n = 135	n = 82	n = 90	n = 90
	n	n	n	n	n	n	n
Smoking free ≥ 30 days	24 (15%)	8 (5%)	14 (9%)	23 (14%)	22 (18%)	28 (24%)	35 (29%)	Chi–square p = 0.003
Smoking free ≥ 6 months	21 (13%)	6 (4%)	10 (6%)	15 (9%)	17 (14%)	25 (21%)	33 (28%)	z–test 3.92 p < 0.001
Smoking free ≥ 1 year	15 (9%)	4 (2%)	8 (5%)	12 (7%)	12 (10%)	24 (20%)	30 (25%)	z–test 3.93 p < 0.001
Mean number of smoking free months	19.7	6.4	11.0	15.1	8.4	16.5	26.1	Median test NS

Group A and group B consist of smokers with normal lung function and group C consists of smokers with COPD. The table shows smoking cessation rates at annual visits throughout the study, point prevalence abstinence (smoking cessation ≥30 days), prolonged abstinence at 6 months and 1 year, and the mean time of the smoking free in months. Mean number of smoking-free months was calculated among those who were smoke free for more than ≥30 days at years 1, 2, and 3.

Table III.  The use of nicotine replacement therapy (NRT), bupropion and snuff in subjects who had stopped smoking (point-prevalence abstinence) and subjects who were still smokers and present at the last annual visit.

	Individuals who stopped smoking n = 82				Individuals who were smokers n = 363
	NRT	Bupropion	Snuff	None	NRT	Bupropion	Snuff	None
Group A n = 165	10(42%)	0 (0%)	3 (12%)	11 (46%)	6 (4%)	0 (0%)	17 (12%)	118 (84%)
Group B n = 161	6 (26%)	1 (4%)	5 (22%)	11(48%)*	18(13%)	0 (0%)	20 (15%)	100 (72%)
Group C (COPD) n = 119	13(37%)	1 (3%)	15 (43%)	6 (17%)*	21(23%)	5 (6%)	12 (13%)	46 (58%)

*Significant difference comparing group B and C among those who stopped smoking.