In this study, the average age of the population was 53 (±11) years and 58.2 % were women. Men were 2 years younger than women and consulted more likely after a hospital contact, whereas women consulted on their own initiative. Women who sought help to quit in SCS were more educated than men and more often in employment. Concerning the medical characteristics, women more often had a depression history, whereas men had medical comorbidities and co-addictions. SC rates were nearly 41 % and did not differ between women and male smokers. At least 4 follow-up consultations with the prescription of nicotine patches, varenicline, or a combination of varenicline and NRT were effective treatments favoring SC, among both, men and women. In the stepwise descending regression analysis, the factors negatively associated with quitting in women were diabetes, intake of mood stabilizers and consuming >10 Cpd while having a chronic bronchitis, taking antidepressants and having consumed cannabis in the last 30 days hampered SC in men.

Concerning socio-demographic data, the larger number of women compared to men, in our population of COPD smokers might be linked to the higher prevalence of smoking among professionally active women with a high level of education in comparison with men (27 % vs 22 %) [25]. Contrary to what was observed in our study, most COPD patients are men. The predominance of female smokers with COPD observed in this study can be explained by the fact that more than half (51.4 %) of the smokers attending SCS are women [26]. In addition, there was a larger-than-expected proportion of the sample who were currently unemployed. In fact, as the SCS are accessible free of charge for the disadvantaged smokers, this percentage is in line with previous research highlighting a higher health service utilization in COPD patients with the lowest socioeconomic status [27].

Smoking behaviors description pointed out that cigarette consumption was higher in our study than in the general population of smokers [28]. Daily cigarette consumption among smokers with COPD and the levels of nicotine dependence for these patients are higher than those of the general population [14].

The 28-day abstinence rate was similar for both sexes, 41 %, despite a lower dependence on tobacco among women than in men. This result was unexpected as the women included in our study had made more previous attempts to quit smoking than the men, the number of previous quit attempts being a key-factor in predicting SC [29]. Women maybe had failed to maintain abstinence and may have chosen to seek help in a SCS to stop smoking for a longer period (>28 days), consistent with the moderate and strong self-efficacy to quit behind these visits. Thus, our data suggest that these women may be multiplying their attempts to stop smoking as a means of consolidating their efforts. This seems to be supported by the observation that women with COPD more frequently consulted on their own initiative than men, who attended SCS more often during or after hospitalization.

As found in our study, abstinence rates for smokers with COPD ranged from 25 % to 52 % between four weeks and five years of follow-up in the literature [[30], [31], [32]]. The SC rates in our study were similar regardless of the initial reasons for consulting, whether on their personal initiative, on the advice of their family and friends, or following referral by a health professional for both sexes or after a hospital contact for women. These results suggest that a key element underlying the success of these smokers with COPD in quitting smoking was access to specialist care in SCS. Following management at a SCS, smokers with COPD can manage to quit, regardless of the profile of associated comorbidities. We found nearly 12 % of current electronic cigarette users among our smokers with COPD. This percentage corresponded to about four times the prevalence of current electronic cigarette use in the general population [33]. These smokers might have encountered difficulties to quit with electronic cigarettes as a smoking cessation aid and sought help in SCS to succeed cessation. Literature in prospective cohorts of COPD smokers has pointed out that electronic cigarette did not help them to quit, maybe because they presented with high nicotine dependence as did the smokers in our study [34].

Identifying associated factors to SC in our population of COPD smokers pointed out that in contrast to men, presenting with diabetes hampered SC among women. In the literature, patients hospitalized with COPD and coexisting diabetes have worse clinical outcomes than patients hospitalized with COPD without diabetes in both sexes [35]. Despite the urgency of SC, several studies point out the difficulty of SC in diabetics despite their knowledge of the negative effects on their health [36,37]. Smoking in these patients may be considered as a way to manage the difficulties associated with diabetes complications or due to the fear of gaining weight while attempting to quit [36,38]. Mood stabilizers prescribed for psychological disorders were also negatively associated with SC in women. Consistent with the literature, these results may be explained by the use of psychotropic medications and the higher prevalence of psychological disorders in women than in men in our study [39]. Psychological disorders, such as bipolar disorder, depression and anxiety, are often considered to be aggravating factors in COPD because they increase the rate of exacerbations and hospitalizations among women [18,40].

In our study, around a third of smokers opted for a reduction in tobacco consumption during the follow-up. Thus, for some smokers, particularly those suffering from smoking-related diseases, a reduction in tobacco consumption may be an option as a preliminary step to smoking cessation [41]. In our results, the female smokers who consumed more than 41 cigarettes per day and the unemployed smokers more frequently reduced their consumption rather than stopping altogether. Heavy smokers with COPD may not have been able to stop smoking completely during the follow-up period. A phase in which tobacco consumption is reduced, with the help of pharmacological treatment, may be an acceptable option for launching an attempt to quit [42].

Our results have some limitations. Unless being consistent with published data on SC among COPD smokers, they cannot be extrapolated to the general population of smokers with COPD. Indeed, we did not have systematically access to pulmonary diagnosis, complementary exams results and therapeutic data of our sample. In addition, we could not determine the duration of lung functional impairment between male and female smokers because CDT-net does not register this kind of specialized medical information. Finally, our study only allowed to obtain short-term abstinence rates in COPD smokers visiting SCS to quit. However, studies have shown that smokers who had been abstinent for four weeks had increased chances of a long-lasting cessation [43]. These limitations do not affect the strengths of the study. One of the main strengths of this study was its power (1470 smokers), with the possibility of a comparison by sex for a large number of sociodemographic, medical, and smoking behavior variables. Our study is original because no real-life studies comparing women and men for such a large number of variables have ever been published, to our knowledge. Consequently, our results focusing on SC among a group of male and female smokers suffering from COPD are on interest for lung specialists to encourage them to systematically offer proactive SC interventions to their patients. In particular, our results highlight the importance of follow-up and of the number of consultations required to help this population of high nicotine dependent smokers with tobacco-related diseases to stop smoking. Finally, self-declared abstinence was validated by systematically measuring CO in exhaled air at all consultations.

Our results suggest that different types of management should be proposed by sex. Intensive management should systematically be offered to men during hospitalization with particularly, screening of cannabis use and a following monitoring after discharge. For women, management should take into account diabetes and psychiatric background to facilitate long-term abstinence. Finally, a reduction of tobacco consumption prior to stopping altogether can be an option as a means of promoting adherence, particularly for smokers with low or moderate self-efficacy to quit. Indeed, only the pro-active management of SC can improve the prognosis of COPD.