The Effects of Smoking Status on Patients in Cardiac Rehabilitation: Results From a National Registry

Purpose: Smoking cessation is challenging, and many patients entering cardiac rehabilitation (CR) continue to smoke. Those who smoke may experience less improvement during CR. This study examined improvements during CR based on smoking status. Methods: Data were collected from patients enrolled between 2012-2021 at CR programs participating in a national registry. Patients were categorized by self-reported cigarette smoking status (current vs. former/never). Variables examined included patient characteristics (age, sex, race, educational attainment, insurance coverage, qualifying diagnosis, and body mass index), number of CR sessions attended, and baseline and change in psychological (depression/anxiety symptoms) and cardiorespiratory fitness (6-minute walk test distance [6MWT], max metabolic equivalent of task [MET]) measures. Baseline values were compared using Chi-square tests or unpaired t-tests as appropriate, and changes in outcome variables were examined using multivariable linear regression. Results: Of the 447 921 patients, 34 656 (8%) reported current smoking at the time of entry. Current smoking was associated with younger age (58.8 vs. 66.9 years), lower socioeconomic status (Medicaid-enrolled, 11% vs. 3%), qualifying for CR due to myocardial infarction (42% vs. 26%), higher anxiety (50.0 vs. 45.3) and depression (6.5 vs. 4.6) scores, lower cardiorespiratory fitness at entry (max MET 3.4 vs. 3.6), and completing fewer CR sessions (17.7 vs. 23.3). Current smoking was independently associated with significantly less improvement in cardiorespiratory fitness (-17.6 meters in 6MWT distance and -0.26 in max MET) and worse depression scores at exit (0.53 higher). Conclusions: Those who enter CR and are smoking are at high risk and may not benefit as much from CR as those who do not smoke. Continued effort must be placed on improving smoking cessation efforts within CR.