The aim of the present study was to evaluate the smoking relapse rate among smokers who had become abstinent during admission for acute coronary syndromes. The association between smoking relapse and mortality was also analyzed. A cohort of 1,294 consecutive active smokers who had interrupted smoking after admission for acute coronary syndromes (1,018 men and 276 women, mean age 59.7 ± 12.3 years) was followed up for 12 months after the index admission. All patients received a brief in-hospital smoking cessation intervention consisting of repeated counseling sessions. During follow-up, 813 patients (62.8%) resumed regular smoking (median interval to relapse 19 days, interquartile range 9 to 76). Increasing age (hazard ratio [HR] 1.034 per year, 95% confidence interval [CI] 1.028 to 1.039, p = 0.001) and female gender (HR 1.23, 95% CI 1.09 to 1.42, p = 0.03) were independent predictors of smoking relapse. Patients enrolled in a cardiac rehabilitation program (HR 0.74, 95% CI 0.51 to 0.91, p = 0.02) and those with diabetes (HR 0.79, 95% CI 0.68 to 0.94, p = 0.03) were more likely to remain abstinent. During follow-up, 97 patients died (1-year probability of death 0.075, 95% CI 0.061 to 0.090). Multivariate analysis with the Cox proportional hazard regression method, including smoking relapse as a time-dependent covariate, demonstrated that, after adjustment for patient demographics, the clinical history features and variables related to the index event, the resumption of smoking was an independent predictor of total mortality (HR 3.1, 95% CI 1.3 to 5.7, p = 0.004). In conclusion, smoking relapse after acute coronary syndromes is associated with increased mortality, and counseling interventions should be integrated into the postdischarge support to reduce the negative effects of smoking resumption.
Smoking cessation has been associated with a significant reduction in mortality after the onset of acute coronary syndromes (ACS). Furthermore, smoking cessation after ACS might be even more effective in improving clinical outcomes than any evidence-based pharmacologic treatment. In light of these major benefits, smoking cessation interventions are recommended for all smokers admitted for ACS. Individual smoking cessation counseling of varying intensity represents the most frequent form of intervention in hospitalized smokers. However, the effectiveness of this behavioral intervention in patients recovering from ACS has not been conclusively established, although high rates of smoking relapse have been reported, despite counseling. Accordingly, the present study was undertaken to evaluate the smoking relapse rate among smokers who had become abstinent during an admission for ACS and had been included in a smoking cessation program on the basis of individual counseling. Moreover, the association between smoking relapse and mortality was analyzed.
Methods
Consecutive patients discharged from our institution after ACS in a 7.5-year period (January 2001 to June 2008) were prospectively screened for inclusion. Patients with non–ST-segment elevation and ST-segment elevation ACS were considered. Our institution is a 750-bed public hospital providing primary and tertiary care to an urban area with about 250,000 inhabitants. In the prespecified selection period, 5,364 consecutive patients with ACS were discharged from our institution. All patients were prospectively asked at admission about their cigarette smoking habits. Patients were then categorized as (1) never smokers, (2) former smokers (abstinence for >1 month before the index admission), or (3) current active smokers.
The consecutive patients categorized as current active smokers who had completely interrupted smoking since admission and declared they were motivated to permanently quit smoking were included in the present study. The patients were excluded in the case of clinical or laboratory evidence of any major concurrent illness, including a history of depression or any other psychiatric affliction, drug or alcohol abuse or dependence, gross cognitive and memory impairment, renal failure, chronic lung disease with respiratory failure, significant liver disease, previous disabling stroke, malignancy, or any other major co-morbidity with a significant reduction in life expectancy. All included patients received a brief in-hospital smoking cessation intervention delivered by either physicians or trained nurses that consisted of repeated counseling sessions lasting 5 to 20 minutes during the index admission (mean number of sessions 3, range 2 to 5). Pharmacologic interventions for smoking cessation, such as nicotine replacement therapy, bupropion, or varenicline, were not used with any patient. After prospective selection, 1,294 consecutive patients, 24.1% of all patients with ACS discharged in the observation period (1,018 men and 276 women, mean age 59.7 ± 12.3 years), who fulfilled the inclusion criteria, provided informed consent and were included in the present study.
A 12-month follow-up period after the index ACS was planned for all patients. The primary outcome measure of the study was prospectively defined as death from any cause within 12 months of discharge after the index admission. This outcome measure was preferred to that of cardiovascular mortality, because the latter has several possible inherent limitations, including incorrect documentation and inaccurate assessment in an environment with low autopsy rates. In the case of death, every effort was made to obtain the hospital records or death certificate.
As in previous studies, and using a previously described protocol, adherence to recommended lifestyle modifications, including smoking cessation, and all prescribed medical therapies, was assessed by structured telephone interviews at 1, 6, and 12 months after discharge. During these interviews, the patients were asked to provide all information about their smoking status after discharge. The interviews were conducted by a trained nurse; various attempts were made to interview individual patients. In the case of failure to interview the patient, all relevant data, including survival and smoking status, were collected from the primary care physicians, who are responsible for clinical follow-up and prescription refilling in the Italian National Health Service. The patients were considered to have relapsed if they reported to have resumed regular smoking according to the National Heart, Lung, Blood Institute definition (i.e., any smoking for 7 consecutive days). In the case of a smoking relapse, particular care was taken to record the date, as reported by both patients and primary care physicians. Overall, this approach allowed us to collect all information about the smoking relapse and clinical outcome in all cases during the 12-month follow-up period; no patient was lost to follow-up.
The mean ± standard deviation was calculated for continuous variables, and frequencies were measured for categorical variables. The cumulative risk of all-cause death was estimated using the Kaplan-Meier method. Multivariate-adjusted Cox proportional hazard regression analyses were used to assess the effect of smoking relapse on the time-related occurrence of the primary outcome measure. Because patients could resume smoking at any point during the follow-up period, Cox models for the association of smoking relapse with mortality included this event as a time-dependent covariate. This approach has already been used in similar previous studies, because patients can be moved from 1 risk class to another at the moment of documented resumption of smoking. In addition, in multivariate analyses, Cox proportional hazards models were constructed to assess the independent association between smoking relapse and the primary outcome measure, adjusting for patient demographics (e.g., age, gender, marital status), educational level, clinical history (e.g., hypertension, diabetes mellitus, previous ACS, previous coronary artery bypass grafting, previous percutaneous coronary intervention, obesity), and variables related to the index event (e.g., left ventricular ejection fraction, interventional procedure, including cardiac catheterization, percutaneous coronary intervention, and coronary artery bypass grafting, and enrollment in a cardiac rehabilitation program). The assumption of proportionality for Cox models was tested and met for all covariates. The results of the Cox proportional hazards models are presented as hazard ratios (HRs) and 95% confidence intervals (CIs). Moreover, because patients were re-evaluated over time for risk exposure and outcome status, according to a statistical approach already used in previous studies, the HRs for the time-related occurrence of total mortality according to the time of smoking relapse were also calculated. Univariate and multivariate Cox proportional hazard regression analyses were also used to identify the clinical and demographic variables associated with smoking relapse during the 12-month follow-up period. The statistical analysis was performed using the Statistical Package for Social Sciences statistical software package, version 13.0 (SPSS, Chicago, Illinois). A p value of <0.05 was considered statistically significant.
Results
During the 12-month follow-up period, 813 patients (62.8%) resumed regular smoking. The median interval from discharge to smoking relapse was 19 days (interquartile range 9 to 76). The Kaplan-Meier actuarial estimates of smoking relapse in the study population are shown in Figure 1 . The main characteristics of the study cohort, as well as unadjusted comparisons between patients who resumed smoking and patients who remained abstinent during the 12-moth follow-up are listed in Table 1 .
| Characteristic | Total Cohort (n = 1,294) | Relapsed Smokers (n = 813) | Abstinent (n = 481) | p Value ⁎ |
|---|---|---|---|---|
| Age (years) | 59.7 ± 12.3 | 63.3 ± 9.7 | 53.7 ± 13.8 | 0.0001 |
| Women | 276 (21.3%) | 203 (24.9%) | 73 (15.1%) | 0.0001 |
| High school education or greater | 361 (27.8%) | 215 (26.4%) | 146 (30.3%) | 0.129 |
| ST-segment elevation acute coronary syndrome | 752 (58.1%) | 471 (57.9%) | 281 (58.5%) | 0.864 |
| Non–ST-segment elevation acute coronary syndrome | 542 (41.9%) | 342 (42.1%) | 200 (41.5%) | 0.863 |
| Obesity (body mass index >30 kg/m 2 ) | 296 (22.8%) | 189 (23.2%) | 107 (22.2%) | 0.678 |
| Diabetes mellitus | 231 (17.8%) | 102 (12.5%) | 129 (26.8%) | 0.0001 |
| Hypertension | 637 (49.2%) | 401 (49.3%) | 236 (49.0%) | 0.928 |
| Previous acute coronary syndrome | 227 (17.5%) | 142 (17.4%) | 85 (17.6%) | 0.925 |
| Left ventricular ejection fraction (%) | 52.5 ± 9.8 | 52.4 ± 9.7 | 52.5 ± 10.0 | 0.990 |
| Previous coronary artery bypass surgery | 39 (3.0%) | 23 (2.8%) | 16 (3.3%) | 0.613 |
| Previous percutaneous coronary intervention | 98 (7.5%) | 68 (8.3%) | 31 (6.4%) | 0.209 |
| Coronary artery bypass surgery during index admission | 18 (1.4%) | 11 (1.3%) | 7 (1.4%) | 0.879 |
| Percutaneous coronary intervention during index admission | 1,063 (82.1%) | 659 (81.0%) | 404 (83.4%) | 0.181 |
| Counseling delivered by nurse | 931 (71.9%) | 573 (70.4%) | 358 (74.4%) | 0.126 |
| Counseling delivered by physician | 363 (28.1%) | 240 (29.6%) | 123 (25.6%) | 0.125 |
| Cardiac rehabilitation after acute coronary syndrome | 91 (7.0%) | 22 (2.7%) | 69 (14.3%) | 0.0001 |
| Estimated glomerular filtration rate at discharge with Modification of Diet in Renal Disease equation † (ml/min/1.73 m 2 ) | 89.6 ± 24.4 | 89.2 ± 24.9 | 90.3 ± 23.6 | 0.457 |
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