Patient enrollment and flow through the trial
Recruitment began in December 1999, and follow-up ended in March 2003. Of the 10 336 admissions to the 4 cardiac units, 19% were because of acute MI (n = 1921) and 14% were for CABG (n = 1425). Of the patients with acute MI, 34% (n = 654) were smokers, and 15% of the patients admitted for CABG (n = 211) were smokers. The overall smoking prevalence rate was 26% (865/3346). Of the patients admitted because of acute MI or for CABG who smoked, 32% were enrolled (276/865) in the study ().
Patient enrollment, allocation, intervention completion and follow-up. Note: CABG = coronary artery bypass graft, MI = myocardial infarction.
All of the patients that were randomly assigned to the minimal intervention and all but 1 of the patients assigned to the intensive intervention received the in-hospital intervention. Of the patients in the intensive intervention, 95% (130/137) received the postdischarge intervention. On average, 93% of patients were available per call, 5% were not reached, and 2% were not called because the research nurse was absent, on vacation or missed a call. Patients received an average of 6.56 (standard deviation 0.8) calls. At the end of the 12-month period, 4 (1%) patients had died, 16 (6%) had dropped out of the study and 9 (3%) were not reached for the final follow-up (i.e., phone line busy, no answer, answering machine, messages not returned).
Stratified randomization resulted in equal numbers of CABG and acute MI patients assigned to each intervention group (). Nine patients did not have an ICD-9 discharge diagnosis code of CABG or acute MI, although they had been admitted for acute MI. There were no significant differences between the groups for medical history () or baseline variables ().
Characteristics of patients admitted to hospital because of myocardial infarction or for coronary artery bypass grafting who received a minimal or intensive intervention for smoking cessation
Demographic characteristics and smoking history of patients admitted to hospital because of myocardial infarction or for coronary artery bypass grafting who received a minimal or intensive intervention for smoking cessation
Self-reported abstinence at 3, 6 and 12 months
More patients in the intensive intervention than in the minimal intervention reported not smoking at 3 months (p = 0.009), 6 months (p = 0.003) and 12 months (p = 0.007) (). The odds of quitting were 2 times greater for patients who received the intensive intervention compared with the minimal intervention at 3, 6 and 12 months (). The reason for admission to hospital (CABG v. acute MI) or the interaction between the intervention and reason for admission did not contribute significantly to the variance in cessation at any follow-up time.
Point prevalence and confirmed rates of abstinence after receipt of a minimal or intensive intervention for smoking cessation
Confirmation of self-reported abstinence
Of the patients who reported not smoking after 12 months, 16% (23/147) did not provide proxy information to allow us to confirm their smoking status. These patients were considered smokers in this analysis. Of the patients who provided proxy information (84%, 124/147), 3 were reported by a friend or family member to have smoked during the past 7 day (2 in the minimal intervention group, 1 in the intensive intervention group). These 3 patients were considered smokers in this analysis.
More patients in the intensive intervention than in the minimal intervention were confirmed nonsmokers at 12 months (p = 0.002) (). There was no significant effect of reason for admission to hospital (CABG v. acute MI) or significant interaction between the intervention and the reason for admission.
Continuous abstinence at 3, 6 and 12 months
The intervention (p = 0.004) and the reason for hospital admission (CABG v. acute MI) (p = 0.04) were significant predictors of continuous abstinence. The interaction between the intervention and having CABG or acute MI was not significant (p = 0.24). Patients who received the intensive intervention had significantly higher rates of continuous abstinence than those who received the minimal intervention (57% [77/135] v. 39% [54/137]; OR 2.1, 95% CI 1.3–3.4, p = 0.003). Patients admitted to hospital for CABG had significantly higher rates of continuous abstinence than those admitted because of acute MI (57% [50/88] v. 44% [81/184]; OR 1.7, 95%CI 1.0–2.9, p = 0.038; ).
Smoking abstinence 12 months after receipt of a minimal or intensive intervention for smoking cessation among patients admitted to hospital for acute myocardial infarction or coronary artery bypass grafting
Although pharmacotherapy was not part of either intervention, it was used by 34% of patients in both groups (minimal intervention: 40/118 patients; intensive intervention: 40/116 patients [data were missing for 19 patients in each group]). Both the intervention and the use of pharmacotherapy were predictors of abstinence (p = 0.001); the interaction between the intervention and the use of pharmacotherapy was not (p = 0.26). Patients who received the intensive intervention had significantly higher odds of being abstinent at 12 months than those who received the minimal intervention (69% [80/116] v. 48% [56/118], OR 2.7, 95% CI 1.5–4.8). In both interventions, patients who used pharmacotherapy had significantly lower odds of being abstinent at 12 months (39% [31/80] v. 68% [105/154], OR 0.3, 95% CI 0.2–0.5; ).
Predictors of 12-month abstinence
Twenty-four patients were missing data for at least 1 of the predictor variables and were excluded from the analyses, leaving a sample size of 248 patients. Significant predictors of the point-prevalence of abstinence at 12 months included receiving the intensive (v. minimal) intervention (OR 2.12, 95% CI 1.2–3.7), having no history (v. having a history) of acute MI before the current admission (OR 2.94, 95% CI 1.3–6.5), having a postsecondary education (v. having a high school education or less) (OR 2.34, 95% CI 1.3–4.1) and having at least some smoking restrictions at home (v. no restrictions) (OR 1.96, 95% CI 1.1–3.5).