A total of 8123 studies were imported for screening. After duplicates were removed there were 4056 studies screened by 2 authors for relevance by title and abstract. Following this, the full-text of n = 41 papers were read in full to determine eligibility and a further 16 studies were excluded leaving a final set of n = 25 articles (Fig. 2).
Of the 25 included articles, 18 were quantitative (18–35), 6 were qualitative (36–41) and 1 used mixed methods (42). The majority of studies were conducted in the US (19, 21, 22, 26–29, 31, 32, 35–37, 39, 40, 42), four were conducted in the UK (18, 25, 38, 41) and one each from Belgium (33), China (20), Greece (24), Iran (30), Poland (34) and Slovenia (23).
Participants qualifications or medical specialities included family physicians/family medicine/family practice/general practitioners/general physicians/primary care physicians (18–42) (this group of participants will be referred to as GPs in this review) and GP trainees (25). Many papers included findings from multiple specialities such as physician assistants (32, 36), nurses/nurse practitioners (23, 24, 28, 32, 36, 41), internal medicine (19, 21, 22, 26, 29, 37, 39), emergency medicine (19), preliminary and transitional medicine (19), medical professionals (undefined) (30), midwives (23, 38), obstetricians/gynaecologists (19, 22, 39, 40), cardiologists (19, 20, 24, 30, 31, 40), neurologists (19, 21), psychiatrists (21, 22), plastic surgeons (19), general surgeons (19, 21, 22, 26), pulmonologists/respiratory physicians (19, 21, 24, 26, 30, 31, 35, 40), pneumologists (20), allergists/immunologists (35), paediatricians (24, 27, 28, 30), internists (24, 30), ophthalmologists (19), anaesthesiologists (19, 26), otolaryngologists (19), orthopaedics (19), oncologists (18, 20, 31, 40), cancer surgeons (18), cancer nurse specialists (18), dentists (24), health visitors (trained nurse) (38) and stop smoking specialists/smoking cessation counsellors/tobacco counsellors (30, 33, 38).
Table 1 presents the characteristics of the quantitative studies and Table 2 those of the qualitative and mixed methods studies.
Table 1
Study characteristics of quantitative studies
Author/Year
|
Study population/ sample size
|
Country/city
|
Study Design
|
Gender
|
Age
|
Brett et al (2020) (18)
|
506 participants
GPs-103
Oncologists-102
Cancer surgeons- 100
Cancer nurse specialists-99
|
England, Wales, Scotland & Northern Ireland
|
Cross-sectional online survey. Face-validity.
Questions developed from previous studies (21, 47, 48).
|
Male-41.1%
Female-57.5%
Prefer not to say- 1.4%
|
N/A
|
Egnot et al (2017) (19)
|
142 participants (338 invited) 42% response rate
Non-surgical clinicians- 102 (internal medicine, family medicine, preliminary and transitional medicine, cardiology, otolaryngology, emergency medicine, pulmonary critical care)
Surgical clinicians- 40 (neurosurgery, plastic surgery, general surgery, obstetrics/gynaecology, anaesthesia, orthopaedics, ophthalmology)
|
Columbus, Ohio, USA
|
Cross-sectional online survey. Validity not established.
Questions on harm reduction developed from previous studies (49).
|
Male- 69
Female- 73
|
Mean age- 28.95 years
|
Feng et al (2019) (20)
|
1023 participants (1291 invited)
Pneumology/cardiovascular/oncology- 190
Others- 833
|
China
|
Cross-sectional online survey. Validity not established. Questions developed from previous studies (26, 50).
|
Male- 692
Female-331
|
20–29 years- 226
30–39 years- 490
40 > years- 307
|
Kanchustambham et
al (2017) (21)
|
115 participants 40% response rate
Internal medicine- 40
Internal medicine sub-specialities- 32
Family medicine- 10
Neurology- 5
Psychiatry- 7
Pulmonary- 14
Surgery- 7
|
Saint Louis University Hospital, Missouri, USA
|
Cross-sectional online survey. Validity not established.
Questions developed from previous studies (not mentioned).
|
N/A
|
N/A
|
Kandra et al (2014) (22)
|
128 participants (787 invited) 31% response rate
Family medicine- 28
Internal medicine- 24
Obstetricians/gynaecologists- 21
Psychiatrists- 27
Surgeons- 28
|
North Carolina, USA
|
Cross-sectional online survey. Validity not mentioned.
|
N/A
|
< 44 years- 47.9%
> 45 years- 52.1%
|
Koprivnikar et al (2020) (23)
|
479 participants (1122 invited)
Nurse or midwife- 356
Physician- 70
Other- 52
|
Slovenia
|
Cross-sectional online survey. Validity not established. Pilot tested. Questions developed from previous studies (21, 26, 40, 48, 51).
|
Male- 47
Female- 431
|
20–39 years- 235 (49.1%)
> 40 years- 244 (50.9%)
|
Moysidou et al (2016) (24)
|
262 participants (865 invited) 30.3% response rate
Physician- 185
Nurse- 77
GP- 17
Cardiologist- 53
Dentist- 32
Internist- 32
Paediatrician- 17
Respiratory physician- 34
|
Athens, Greece
|
Cross-sectional online survey. Validity not established.
|
Male- 138
Female- 124
|
Mean age- 39 years
|
Mughal et al (2018) (25)
|
312 participants
GPs- 117
GP trainees- 189
|
UK
|
Cross-sectional online survey. Pilot tested.
Validity not established.
|
Male- 110
Female- 201
|
N/A
|
Nickels et al (2017) (26)
|
561 participants (1500 invited) 44% response rate
Anaesthesiology- 64
Family practice- 97
General surgery- 107
Internal medicine- 89
Pulmonary- 204
|
USA
|
Cross-sectional postal survey. Face-validity and cognitively tested.
|
Male- 464
Female- 97
|
Mean age- 57.2 years
|
Pepper et al (2015) (27)
|
776 participants (2368 invited) 33% response rate
Paediatrics- 410
Family medicine- 366
|
USA
|
Cross-sectional online survey. Pilot tested.
Validity not mentioned
|
Male- 526
Female- 250
|
N/A
|
Pepper et al (2014) (28)
|
561 participants (3923 invited) 28% response rate
Family medicine- 258
Paediatrician- 114
Nurse practitioner- 189
|
Minnesota, USA
|
Cross-sectional online survey. Validity not mentioned. Cognitively tested.
Questions developed from previous studies (52).
|
Male- 161
Female- 400
|
Mean age- 47.8 years
|
Salloum et al (2021) (29)
|
216 participants (801 invited) 28.7% response rate
Family medicine- 98
Internal medicine- 103
Missing- 15
|
Florida, USA
|
Cross-sectional state-wide postal survey.
Questions guided and developed from previous studies (22, 42, 53). Face-validity and cognitively tested.
|
Male- 163
Female- 46
Missing-7
|
Mean age- 58.6 years
|
Sharifi et al (2019) (30)
|
147 participants
Medical professionals, smoking cessation counsellors, respiratory physicians, cardiologists, internists, paediatricians & GPs
|
Iran
|
Cross-sectional postal survey. Questions developed from previous validated studies (43).
|
Male- 49
Female- 98
|
Mean age- 41.05 years
|
Steinberg et al (2015) (31)
|
158 participants 2.25% response rate (pilot study)
Primary care- 62
Specialists (tobacco diseases) oncologists, cardiologists, pulmonologists- 96
|
USA
|
Cross-sectional online survey. Validity not mentioned
|
Male- 44
Female-112
Missing-2
|
N/A
|
Talley et al (2017) (32)
|
80 participants (181 invited) 44% response rate (pilot study)
Physician- 48
Nurse- 8
Physicians’ assistant- 6
Nurse practitioner- 16
Other (general or family practice)- 2
|
USA
|
Cross-sectional online survey. Validity not mentioned.
|
Male- 41
Female- 39
|
Mean age- 45.6 years
|
Van Gucht & Baeyens (2016) (33)
|
76 participants
GPs- 22 (29%)
Tobacco counsellors- 54 (71%)
|
Flanders, Belgium
|
Cross-sectional online questionnaire. Some questions developed from previous studies (22). Validity not mentioned.
|
Male: GPs- 33%
Tobacco counsellors- 40%
Female: GPs-67%
Tobacco counsellors- 60%
|
Mean age- 45 years
|
Zgliczynski et al (2019) (34)
|
412 participants (500 invited) 82.4% response rate
Physicians
|
Poland
|
Cross-sectional postal survey. Face-validity.
Questions developed from previous studies (22, 28, 33).
|
Male- 147
Female- 265
|
Mean age- 31.9 years
|
Zhou et al (2020) (35)
|
291 participants 46% response rate
Primary care physicians (internists, paediatricians or family medicine physicians)- 222
Pulmonary- 33
Allergists/immunologists- 36
|
Michigan, USA
|
Cross- sectional online survey.
Questions developed from previously validated surveys (54, 55).
|
Male- 160
Female- 131
|
< 30 years- 125
31–40 years- 70
41–50 years- 42
51–60 years- 34
> 60 years- 20
|
Table 2
Study characteristics of qualitative studies
Author/Year
|
Study population/ sample size
|
Country/city
|
Study Design
|
Gender
|
Age
|
Bacombe et al (2016) (36)
|
20 interviews
Physicians-15
Nurses-3
Physician assistants-2
Georgia- 6
Atlanta- 60 invited, 14 interviewed
|
Atlanta metro and rural southern Georgia, USA
|
Semi-structured interviews.
|
Female-13
Male-7
|
Average- 45.25
|
El-Shahawy et al (2016) (37)
|
15 interviews
11- Family medicine physicians
4- Internal medicine physicians
University health system- 46 invited, 7 interviewed
ACORN- 26 invited, 8 interviewed
|
Virginia, USA
|
Semi-structured interviews.
|
Female- 47%
Male- 53%
|
Average- 43.1
|
Hunter et al (2021) (38)
|
60 interviews
17-midwives
10-health visitors
15-general practitioners
18-stop smoking specialists
|
UK (including Wales and Northern Ireland)
|
In-depth interviews.
|
Female-50
Male-10
|
18–25 years- 3
26–35 years- 16
36–45 years- 13
46–55 years- 21
56–65 years- 6
66 + years- 1
|
Kollath-Cattano et al (2019) (39)
|
14 interviews (18 expressed interest)
5-internal medicine
6-family medicine
3-obstretics/gynaecology
|
South Carolina, USA
|
Semi-structure interview.
|
N/A
|
N/A
|
Ofei-Dodoo et al (2017) (42)
|
117 family physicians (154 invited)
|
Kansas, USA
|
Mixed methods.
Questionnaire and
in depth interviews
|
Female-50
Male-57
|
N/A
|
Singh et al (2017) (40)
|
35 interviews
10-Primary care physicians
10- Obstetrics/gynaecology
5-Cardiologists
5- Pulmonologists
5- Oncologists
|
USA
|
Semi-structured interview.
|
Female- 8
Male- 27
|
Average- 55.5
|
Stepney et al (2019) (41)
|
23 interviews (45 invited)
15-general practitioners
8-nurses
|
Thames Valley and South Midlands, West of England, Eastern and East Midlands, UK
|
Interviews.
|
N/A
|
N/A
|
Synthesis of studies using a quantitative design
Findings from eighteen quantitative studies were included in the synthesis (18–35). From the eighteen quantitative papers six articles used validated instruments (18, 26, 29, 30, 34, 35), three articles used instruments that were cognitively tested (26, 28, 29) and 11 articles adapted questions from other published studies (18–21, 23, 28, 29, 33–35, 43).
Data were explored to understand (1) knowledge, (2) attitudes and beliefs, (3) recommendations and, (4) comfort and confidence levels of GPs when discussing e-cigarettes with patients.
Perceived knowledge of e-cigarettes as a smoking cessation aid
Across the studies, GPs had limited knowledge of e-cigarettes however, they were reported as having greater knowledge of e-cigarettes than paediatricians, nurse practitioners and cancer surgeons (18, 24, 28). GPs wanted to receive training and learn more about e-cigarettes for smoking cessation to better advise their patients on suitability of using e-cigarettes to quit smoking (18, 27, 28, 30, 32, 34).
Information regarding e-cigarettes was sought by GPs from government/health organisations, healthcare colleagues, news/media/advertisement, scientific literature, professional organisations, professional guidelines/development/training, charities, family members, friends and patients (18, 19, 28, 29, 34).
Attitudes and beliefs of GPs on e-cigarettes for smoking cessation
The majority of GPs surveyed in four studies (25, 32, 34, 35) believed e-cigarette use to be harmful, while other studies reported that GPs thought e-cigarettes were less harmful than regular cigarettes (24, 27, 28, 30). In one study, 25% of respondents were unsure if e-cigarettes were less harmful than standard cigarettes (18) and in another, GPs somewhat agreed that e-cigarettes were safer than other tobacco products (28).
In other studies, GPs commented on the possibility that e-cigarettes could be a gateway to smoking especially amongst adolescents and non-smokers (21, 27, 28, 33, 34), and felt it was important to address this issue with patients (28).
There were mixed views amongst tobacco counsellors and GPs on the use of e-cigarettes as smoking cessation aids. In Belgium, tobacco counsellors ‘totally disagreed’ more than GPs (24% vs 5%) that e-cigarettes were an effective method to quit smoking (33).
In regards to whether e-cigarettes containing nicotine are addictive, in one study, 46% of GPs totally agreed compared to 56% of tobacco counsellors. Similarly, 18% of GPs totally disagreed that e-cigarettes without nicotine are addictive compared to 20% of tobacco counsellors (33).
GPs recommendations of e-cigarettes as a smoking cessation aid
Despite the mixed views about use of e-cigarettes as a smoking cessation aid, the majority of studies included in this review did not agree that e-cigarettes should be recommended as a smoking cessation treatment (19, 23, 24, 29, 33–35, 39–42). In saying that, one study did find that if patients asked about e-cigarettes, GPs, would recommend them regardless of the lack of research and evidence behind the effectiveness and safety of the product (31).
GPs comfort and confidence levels discussing e-cigarettes with patients
One study reported that under half of GPs (48.2%) felt confident in their level of knowledge and capability to respond to patient questions compared to pulmonologists (65.5%) and surgical care providers (18.5%) (general surgeons/anaesthesiologists) (26).
In regards to comfort levels, a study in the US reported that GPs had higher knowledge and awareness of e-cigarettes than nurses and paediatricians, and were more comfortable with patient’s e-cigarette inquiries (28). Similarly in another US study, GPs reported being more comfortable offering e-cigarette advice compared to allergy physicians (35).
Pepper et al (28) compared younger and older GPs and found that younger GPs, had greater awareness of e-cigarettes but were not considered to be more comfortable around patients discussing e-cigarettes. Moysidou et al (24) did not report on the exact figures of how many GPs thought e-cigarettes should be available on prescription, rather this was reported across physicians as a whole. Physicians (43.8%) believed that e-cigarettes should only be available on prescription and 45.4% of them thought e-cigarettes should be licensed as medications (24). Moreover, fewer than half of physicians (40.5%) believed that e-cigarettes should only be sold in pharmacies (24).
Synthesis of studies using qualitative design
Findings from the six qualitative studies were included in the qualitative data synthesis (36–41) together with findings from the sole mixed method study (42). Interview guides were used in all the studies and covered similar topics such as, beliefs, attitudes and perceptions, general knowledge, recommendations and screening and counselling practices for e-cigarettes. Studies assessed these issues in the context of the general population whereas Hunter et al (38) was the only study that looked at these issues in the context of pregnancy and postpartum women. Kollath-Cattano et al (39), was the only mixed method study and findings are included within the qualitative synthesis.
Interview questions reported in these studies asked about attitudes and beliefs of e-cigarettes as a smoking cessation aid such as, “what are your thoughts regarding e-cigarettes?” (37, 38, 40–42), “what are your perceptions on the safety and efficacy of e-cigarettes?” (38, 39, 42) and, “did you/have you recommended e-cigarettes to quit smoking?” (36–38, 42). Only two studies asked about prescribing and licensing with “how do you feel about the licensing of e-cigarettes?” (38, 41).
Three themes were prominent among the included studies. These included (1) knowledge, practice and beliefs, (2) concerns around lack of research and evidence and (3) e-cigarettes becoming an increasingly common topic in clinical consultations.
Theme 1: Knowledge, practice and beliefs of e-cigarettes as a smoking cessation aid
GPs held concerns around the safety and efficacy of e-cigarettes as a smoking cessation aid and believed there to be insufficient data on these issues (37, 40, 42). They were also apprehensive about the health implications, long-term health risks that e-cigarettes may present and believed e-cigarettes are not completely risk free (36, 38).
“I tell them [patients] the jury is still out. We don't know about the long-term safety, we don't know about the efficacy [of e-cigarettes]” (primary care) (40)
GPs held concerns that e-cigarettes were not suitable for smoking cessation as they “still contained nicotine” and that there remains a lack of data and knowledge to claim e-cigarettes as an effective method to quit smoking (42).
GPs held concerns about the increasing use and popularity of e-cigarettes amongst young people, adolescents and non-smokers as e-cigarettes were becoming a gateway to smoking for many of their patients in the US and UK (40, 41). Many believed e-cigarettes to be a gateway for non-smokers to smoke combustible cigarettes and other tobacco products and for smokers, there were concerns around dual use (38).
“I am most concerned about gateway to other tobacco products and also impact on minors. I think that's a big one and I'm very, very concerned about that.” (primary care) (40).
GPs had mixed views recommending e-cigarettes for smoking cessation. Most were reluctant to recommend e-cigarettes due to insufficient research around the safety and long-term health effects (38, 39, 42). GPs were adamant the only way they would recommend or prescribe e-cigarettes for smoking cessation and take responsibility for their action, is if it has been approved by a regulatory authority (39, 41, 42).
“[They are] not regulated by [the] FDA and this seems to be a dangerous thing with possible carcinogenic effects.” (family physician) (42)
Theme 2: Concerns around lack of research and evidence
All seven studies identified a need for further research and information on e-cigarettes to support their clinical practice and ability to advise patients (36–42).
GPs indicated the lack of reliable scientific evidence about the safety of e-cigarettes as a major concern. They required more information on the long-term health effects before supporting and recommending the use of e-cigarettes as a smoking cessation treatment (36–42).
“Unless you show me some real evidence and the United States Preventative Task Force recommends it, I'm probably not going to [recommend e-cigarettes].” (family medicine) (39)
“There is not significant evidence showing e-cigarettes are effective in assisting in tobacco cessation.” (family physician) (42)
Theme 3: E-cigarettes becoming increasingly common in clinical consultation
As e-cigarettes are becoming more common and readily available, smokers are increasingly seeking information and advice from their GPs on the potential harms and benefits for using e-cigarettes, including their possible role in supporting quit attempts. Three studies described GPs perceptions that their patients were initiating discussions more and more often with their GPs in clinical visits about e-cigarettes (37, 39, 40).
“E-cigarettes have definitely been coming up in the last six months, maybe the last year. More patients are mentioning it as an alternative or something they are looking to instead of traditional smoking.” (primary care physician) (37)
On the contrary, in some GP practices discussions of e-cigarettes did not take place (36), and in practices that it did, GPs didn’t feel they had a place or role to help patients quit smoking as their patients knew more about e-cigarettes than they did (41).