Baseline characteristics
In total, 221 participants were enrolled. General characteristics and smoking characteristics of participants were balanced across study groups (Table 1). Numeric variable data are expressed as median (25th-75th percentile). Participants were predominantly male (91.9%), married (89.1%), non-living alone (94.1%) and have stable job (81.0%). The middle age of enrolled participants was 45 years old. Most of them have received education, thus we divided them into two categories according to whether they had completed university education. The median monthly income was between CNY (Chinese Yuan) 3000 and 6000.
Participants smoked a median of 20.0 cigarettes per day, with a median smoking age 22.0 years. Tobacco dependence is dominated by moderate to severe dependence, and median CO value before the start of smoking cessation is 9.0.
Table 1 Baseline Characteristics of Smokers
Characteristics
|
Total
|
Control[n(%)]
|
Physician Enrolled Group[n(%)]
|
P value
|
Patients
|
221
|
98
|
123
|
-
|
General Characteristics
|
|
|
|
|
Gender (male)
|
203(91.9)
|
90(91.8)
|
113(91.9)
|
0.993
|
Age (years)
|
45(35-53)
|
43(35.5-53)
|
43(35-54)
|
0.656
|
Education
|
|
|
|
0.852
|
Below bachelor degree
|
94(42.5)
|
41(41.8)
|
53(43.1)
|
|
Bachelor degree or above
|
127(57.5)
|
57(58.2)
|
70(56.9)
|
|
Marital Status
|
|
|
|
0.144
|
Marriage
|
197(89.1)
|
84(85.7)
|
113(91.9)
|
|
Single/divorced/widowed
|
24(10.9)
|
14(14.3)
|
10(8.1)
|
|
Living Condition
|
|
|
|
0.505
|
Living alone
|
13(5.9)
|
7(7.1)
|
6(4.9)
|
|
Living with families or others
|
208(94.1)
|
91(92.9)
|
117(95.1)
|
|
Occupation
|
|
|
|
0.387
|
Unemployment/temporary job
|
42(19.0)
|
18(18.4)
|
24(19.5)
|
|
Outdoor stable work
|
111(50.2)
|
54(55.1)
|
57(46.3)
|
|
Indoor stable work
|
68(30.8)
|
26(26.5)
|
42(34.1)
|
|
Income
|
|
|
|
0.966
|
<¥3000
|
68(30.8)
|
31(31.6)
|
37(30.0)
|
|
¥3000-6000
|
77(34.8)
|
34(34.7)
|
43(35.0)
|
|
>¥6000
|
76(34.4)
|
33(33.7)
|
43(35.0)
|
|
Smoking Characteristics
|
|
|
|
|
Cigarettes per day
|
20(15-20)
|
20(15-25)
|
20(12-20)
|
0.972
|
Number of year smoking
|
22(14-30)
|
22(13.5-30)
|
22(15-30)
|
0.168
|
Tobacco dependence
|
|
|
|
0.215
|
Mild
|
63(28.5)
|
23(23.5)
|
40(32.5)
|
|
Moderate
|
82(37.1)
|
36(36.7)
|
46(37.4)
|
|
Severe
|
76(34.4)
|
39(39.8)
|
37(30.1)
|
|
CO Value
|
9(7-12)
|
9(7-13)
|
9(7-11)
|
0.154
|
Primary Outcome of Respiratory Physicians Participating in Smoking Cessation
The primary outcome was collected at 3 months and 6 months after beginning quitting smoking. Successful smoking cessation needs to meet self-reported 30-day non-smoking and exhaled gas CO≤ 3ppm.
After beginning quit for 3 months, the group with respiratory physicians actively involved was successful in 80 cases, the success rate was 65.0% (80/123); the control group was successful in 34 cases, the success rate was 34.7% (34/98). After beginning quit for 6 months, the group with respiratory physicians actively involved was successful in 68 cases, the success rate was 55.3% (68/123); the control group was successful in 11 cases, the success rate was 11.2% (11/98). There was a statistically significant difference between the two groups, that is, the smoking cessation rate of the group with respiratory physicians actively involved was significantly higher than that of the control group (Table 2).
Table 2 The Rate of Quitting for Three Months and Six Months
|
Total
|
Control [n(%)]
|
Physician Enrolled Group[n(%)]
|
χ2
|
P value
|
Three Months (Success,%)
|
114
|
34 (29.8)
|
80 (70.2)
|
20.112
|
0.000
|
Six Months (Success,%)
|
79
|
11 (13.9)
|
68 (86.1)
|
46.100
|
0.000
|
The physician enrolled group was successful in 80 cases, the median weight increased by 0.32 kg in three months, the maximum increase of 3.27 kg; the control group succeeded in 34 cases, the median weight increased by 0.33 kg, the maximum increase of 1.73 kg. There was no significant difference in BMI between the two groups before and after smoking cessation. However, in each group, successful smoking cessation has statistically significant effect on weight change.
Factors Affecting the Success Rate of Smoking Cessation and Subgroup Analysis
Univariate analysis of gender, marital status, current living conditions, income, age, smoke years, smoking count (branch/day), expiratory carbon monoxide, and nicotine dependence. When it comes to the successful rate of quitting 3 months, education, exhaled carbon monoxide and whether there is physicians participation are statistical differences (Table 3). Multivariate analysis was performed with a P < 0.05 factor. Among them, doctor participation (OR=3.371) and higher education (OR=2.113) contribute to the improvement of the success rate of smoking cessation, but the higher the CO value (OR=0.908), the lower the success rate of smoking cessation.
However, at 6 months, doctor participation in the promotion of smoking cessation rate is significantly more important than other factors (OR=9.320).As a recognized indicator of the degree of smoking, CO value (OR=0.927) is still instructive for the success or failure of smoking cessation rate (Table 3).
Since doctors' participation in smoking cessation for three months does not have such a significant effect in improving the success rate of smoking cessation like smoking cessation for six months, we would like to know further whether doctor participation in different subgroups will affect the success rate of smoking cessation, so we conducted a subgroup analysis (figue 2A).
The results showed that among men who were younger than 45 years old or unemployment, doctors' participation has a greater impact on the success of smoking cessation. Among the heavy smokers, the participation of doctors is more convince than light smokers during smoking quiting.
Table 3 Univariate and Multivariate analyses of various parameters in successful quitting smokers after three months
|
Univariate analyses
|
Multivariate analyses
|
P
|
Odd Ratio
|
95% confidence interval
|
P
|
Odd Ratio
|
95% confidence interval
|
Successful quitting after three months
|
Gender
|
0.888
|
1.071
|
0.409-2.810
|
|
|
|
Age
|
0.453
|
0.991
|
0.968-1.015
|
|
|
|
Education
|
0.021
|
1.885
|
1.098-3.234
|
0.012
|
2.113
|
1.184-3.770
|
Marital Status
|
0.869
|
1.074
|
0.460-2.506
|
|
|
|
Living Condition
|
0.866
|
0.908
|
0.295-2.794
|
|
|
|
Occupation
|
0.280
|
1.234
|
0.843-1.806
|
|
|
|
Income
|
0.140
|
1.282
|
0.922-1.783
|
|
|
|
Cigarettes per day
|
0.453
|
0.991
|
0.967-1.015
|
|
|
|
Number of year smoking
|
0.008
|
0.963
|
0.937-0.990
|
|
|
|
Tobacco dependence
|
0.424
|
0.872
|
0.624-1.219
|
|
|
|
CO Value
|
0.004
|
0.893
|
0.826-0.965
|
0.017
|
0.908
|
0.836-0.985
|
Physician Participation
|
0.000
|
3.502
|
2.006-6.113
|
0.000
|
3.371
|
1.891-6.010
|
|
|
|
|
|
|
|
Successful quitting after six months
|
Gender
|
0.772
|
0.864
|
0.321-2.325
|
|
|
|
Age
|
0.928
|
1.001
|
0.977-1.026
|
|
|
|
Education
|
0.113
|
1.582
|
0.897-2.788
|
|
|
|
Marital Status
|
0.250
|
1.766
|
0.671-4.650
|
|
|
|
Living Condition
|
0.333
|
1.919
|
0.512-7.189
|
|
|
|
Occupation
|
0.343
|
1.213
|
0.814-1.806
|
|
|
|
Income
|
0.471
|
1.134
|
0.805-1.597
|
|
|
|
Cigarettes per day
|
0.909
|
1.001
|
0.977-1.027
|
|
|
|
Number of year smoking
|
0.119
|
0.978
|
0.950-1.006
|
|
|
|
Tobacco dependence
|
0.518
|
0.892
|
0.630-1.263
|
|
|
|
CO Value
|
0.022
|
0.905
|
0.831-0.986
|
0.117
|
0.927
|
0.844-1.019
|
Physician Enrolled or Not
|
0.000
|
9.779
|
4.755-20.108
|
0.000
|
9.320
|
4.516-19.235
|
Cause Analysis of Relapse
We found that relapse is a major obstacle to the success rate during smoking quitting, we thus analysis participants who successed quitting smoking at 3 months and relapsed at 6 months in each group. Among all participants who had relapse, 23 patients in the control group (figure 2B) had relapse, the relapse rate was 67.6% (23/34), and 12 patients in the physician enrolled group (figure 2C) had relapse, the relapse rate was 15% (12/80). Therefore, doctor participation is also crucial to reduce the relapse rate. Further, we investigated the reasons for relapse. We found that smoking addiction is the main cause of relapse. Social pressure, the surrounding environment and stress work also have a certain impact on the existence of relapse.