The aim of this study was to compare the odds of smoking cessation at 2-months post-MI before versus after implementing a set of pre-specified routines for optimization of evidence-based treatment methods for smoking cessation, with start during admission.
A retrospective observational multicentre cohort study.
Setting and participants
As a joint venture for clinical quality improvement, structured routines for early smoking cessation counselling and treatment optimization were implemented at six hospitals in Sweden in 2018-2019. Two are university hospitals. The largest hospital is situated in Malmö, the third largest city in Sweden. Two are of medium size (Örebro and Jönköping) and three are smaller urban or rural hospitals (Trelleborg, Eksjö and Värnamo). The three largest hospitals have acute percutaneous coronary intervention facility, and all have a coronary intensive care unit and an outpatient cardiac rehabilitation (CR) centre. The CR team in Malmö was the first to start implementing the new working routines. The Malmö team thereafter visited the other hospitals to introduce the CR and coronary intensive care personnel to the new routines and support implementation.
The participating CR centres report to the SWEDEHEART registry 6 and provide comprehensive CR to post-MI patients. The “usual care” CR programme starts with an individual patient assessment with a nurse at 2-3 weeks after discharge, followed by two registry-based nurse visits at 6-10 weeks (2-month visit) and 11-13 months (1-year visit). Central components of the programme include control and treatment of cardiovascular risk factors, interactive patient education, psychosocial management, smoking cessation counselling (individual or group therapy) if needed, individual patient assessment with a physiotherapist, and supervised centre-based exercise training.
The new routines
The newly adapted routines included the following:
- A CR nurse should identify all actively smoking MI-patients while still hospitalized for their MI and offer a short consultation with the patient during admission. A new information pamphlet for patients was designed, which included information on the benefits of smoking cessation, tips for avoiding relapse after discharge, plan for follow-up and contact information for the CR centre and generally available anti-smoking aid (telephone and online support).
- The CR nurse should give advice to the coronary intensive care nurses and physicians on optimal dosage of NRT during admission and encourage prescription at discharge (even though NRT is available over the counter in Sweden), as an attempt to increase adherence.
- The CR nurse should identify eligible patients for treatment with varenicline, and alert the responsible physician, who in turn would initiate treatment if deemed suitable.
- Varenicline treatment should preferably be started before discharge.
- The patient should be contacted by telephone, by the same nurse that consulted the patient during admission, during the first week after discharge. Thereafter, usual care CR commenced.
- If the patient opted out from varenicline treatment during admission and was still smoking at the telephone contact or 1st CR follow-up visits, treatment should be offered again.
- Finally, centres were encouraged to strive for continuity in nurse-patient care, meaning the same CR nurse should care for the patient from the first contact during admission throughout CR follow-up.
As such, the CR nurse was the key professional in implementing the new routines. CR nurses at all participating centres had tobacco counselling qualifications prior to the start of the project. If requested, a brief refreshment course and coaching guide was provided by a tobacco counsellor. At some centres, the routines were predominantly new, and at others only smaller amendments or refreshing of routines were needed (see Supplementary Table 1).
Data collection and outcomes
Smoking cessation at 2-months post-MI for currently smoking patients aged 18-74 years admitted to the coronary intensive care units at the participating hospitals with a type-1 MI, before (reference period) and after (implementation period) routine implementation, were compared. The implementation and reference periods were of equivalent length at each participating hospital. For the three hospitals with the longest implementation periods (8-14 months), the end of the reference period was set one month prior to start of the implementation period. The remaining three hospitals had shorter implementation periods (4 months), and for which the same period the year prior to the implementation year, was used to minimize seasonal bias. The start and length of the study periods per hospital is listed in Supplementary Table 2. Baseline data and smoking status at 2-months was retrieved from the SWEDEHEART registry. Current smoking was self-reported and defined as daily smoking during the last month. Adherence to the pre-set routines was retrieved from patient journal records at each participating hospital.
According to the original study protocol, primary outcome was smoking abstinence at the 1-year follow-up visit. Since the Covid-19 pandemic started at the time the last patients included in the implementation period had their 2-month follow-up - seriously debilitating planned follow-up routines at all CR centres - primary outcome was changed to smoking abstinence at 2-months post-MI. Secondary outcomes included (i) adherence to the newly implemented routines and (ii) prognostic value of each of the new routines for smoking abstinence at 2-months. Continuity in nurse-patient care was defined as 2/3 or more of same nurse-patient contact (physical visits during admission and follow-up and telephone contacts during follow-up).
Availability of data and materials
The SWEDEHEART registry data that support the findings of this study are available from Uppsala Clinical Research Center (UCR) in Sweden but restrictions apply to the availability of these data, which were used under license for the current study, and so are not publicly available. Third-party data usage is not allowed, irrespective of whether the data contain potentially identifying or sensitive data or not. Instead, given ethical study approval from the Swedish Ethical Review Authority, access to SWEDEHEART data supporting the present findings can be applied for from UCR. Further information can be found on the UCR (www.ucr.uu.se/en/) and Swedish Ethical Review Authority (etikprovningsmyndigheten.se) websites. The study protocol has not been previously published but is available from the corresponding author on reasonable request.
Ethics approval and consent to participate
The Swedish Ethical Review Authority approved the study (2019-06177). As it involved evaluating outcomes after implementing evidence-based and guideline-recommended clinical routines in daily practice, the need for informed consent was waived. As for SWEDEHEART data, a nurse or physician verbally informs all eligible patients at hospital admission of their registration and opt-out rights. All patients have the right to deny registration and retain the right to be removed from the registry at any time.
Sample size calculations
In the randomized controlled double-blind Evaluation of Varenicline in Smoking Cessation for Patients Post-Acute Coronary Syndrome (EVITA) trial, patients with acute coronary syndrome and who were smokers at baseline were randomized to receive either varenicline or placebo before discharge 11. In the intervention arm, 58% of patients were smoke-free at first follow-up (12 weeks), compared to 36% in the placebo arm (21.3% difference, p<0.0001). In the current study, at the CR centres implementing the new routines, 59% of current smokers at the time of MI were abstinent at the first SWEDEHEART follow-up (6-10 weeks) in 2017 15. Based on EVITA results, we concluded that a 15%-point change improvement in smoking cessation rates was a reasonable target for the current study. A somewhat lower improvement rate compared to EVITA was expected because the proportion of smokers abstinent at 2-months is already quite high and not all patients were expected to be identified and thus potentially benefitting from the new routines. With a power of 80% and a two-sided significance level of 0.05 we calculated that we need to include 150 patients in each group.
Baseline patient characteristics are presented as medians (q1, q3) and percentages. Adherence to the implemented routines are described using percentages and comparisons made using chi-square test. The primary and secondary outcomes were analyzed using logistic regression. The primary outcome analysis was first done for all current smokers admitted during the predefined implementation period (intention to treat) and thereafter including only current smokers counselled during admission (per protocol). For the secondary outcomes, each routine´s association with smoking cessation at 2-months for patients from the implementation period only were evaluated. Finally, all routines were included as independent variables simultaneously. For all regression analyses, crude models were fitted, whereafter models were adjusted for age, gender, size of center (small, medium, large), length of hospital stay, and whether the patient was discharged during the weekend (Saturday-Sunday), Mondays or during holidays. Mondays were included as patients discharged on Mondays often had returned home before the nurse had a chance to consult the patients.