Carbon monoxide monitoring to objectively measure smoking status in cardiac rehabilitation.

objectiveParticipation in cardiac rehabilitation (CR) is associated with reduced morbidity and mortality. However, most programs rely on self-report measures when assessing the critical risk factor of smoking. This study examined smoking status using self-report versus objective measurement using expired carbon monoxide (CO) and compared patient characteristics by CO level.

methodPatients were screened for smoking status when entering CR by self-report and by objectively measured CO. Measures of aerobic fitness, educational attainment, depressive symptoms, and self-reported physical function were also collected. The discrepancy between smoking status based on self-report and objective measurement was examined and patient characteristics by CO measurement were compared.

resultsOf the 853 patients screened, 62 self-reported current smoking and 112 had a CO of ≥ 4 ppm. Using a cut-off of ≥ 4 ppm encompassed almost all self-reported smokers (specificity: 98.5%) and identified 61 patients (not reporting current smoking) needing further screening. Further questioning yielded an additional 21 patients with combusted use (tobacco/cannabis), six nonsmoking patients with environmental CO exposure, and 34 where the reason for elevated CO was unknown. CO ≥ 4 ppm patients were younger (62.2 vs. 67.7,

conclusionsA substantial number of patients who are actively smoking may be misclassified by relying on patient report alone. CO monitoring provides a simple and objective method of systematically screening patients. (PsycInfo Database Record (c) 2022 APA, all rights reserved).