The association of sociodemographic variables with smoking prevalence in patients enrolled on clinical trials.
Authors: Presant Cary A. , Vaidya Riha , Till Cathee , Ashing Kimlin Tan , Warren Graham W. , Hershman Dawn L. , Sun Virginia , Subbiah Shanmugga , Salgia Ravi , Massarelli Erminia , Mortimer Joanne E. , Fakih Marwan , Pal Sumanta Kumar , Amini Arya , Erhunmwunsee Loretta , Phillips Tanyanika , Rosen Steven T. , Unger Joseph M. 
Published: June 2023

e13595

Background: Smoking in cancer patients (pts) causes reduced clinical benefits and increased toxicity. Smoking prevalence in clinical trial participants is not well documented. We examined the association of sociodemographic variables with smoking prevalence in SWOG clinical trial enrollees. Methods: Data from 29 clinical trials conducted between 2016-2022 by the SWOG Cancer Research Network were evaluated for baseline smoking status (never, former [no smoking for > 1 year], recent [quit < 1 year ago] and current), by age, sex, race, ethnicity, rurality, geographic region, insurance type and neighborhood area deprivation index (ADI). Statistical analysis included Chi Square tests and multinomial logistic regression to examine associations of smoking status with baseline characteristics. Current and recent (C/R) smoker categories were combined. Results: Of 4627 pts enrolled to clinical trials, 3896 pts (84.2%) with documented baseline smoking status and other characteristics were evaluable. Among these, 17.4% reported C/R smoking, 31.0% former smoking, and 51.6% never smoking. Overall, 85% of pts were White, 10.6% were Black, and 3.4% were Asian/Pacific Islander; Hispanic pts were 6.2% of enrollees. C/R smoking was reported in 32.9% of lung, 20.0% of breast, 19.4% of lymphoma, 17.6% of GU, 17.4% of GI, and 14.9% of melanoma cancer pts. C/R smoking was associated with non-Hispanic vs. Hispanic pts (18.0% vs. 9.5%), and with Black (24.4%) and White (17.0%) pts vs. Asian/Pacific Islander pts (6.8%). Among adults aged 18-64 years, 20.9% reported C/R smoking compared with 13.3% in adults >65. In bivariate analyses, baseline smoking status varied by all individual patient characteristics (p<.001). In multinomial logistic regression analysis, C/R smoking was associated with lung cancer pts (OR=6.3, 95% CI 3.5-11.4, p<.001), male pts (OR=1.31 95% CI 1.06-1.6, p=.01), and pts living in areas of greater deprivation (ADI quartile 4 vs. quartile 1: OR=2.15, 95% CI 1.5-3.0, p<.001). Pts with Medicaid or no insurance were more likely to report C/R smoking compared with private insurance (OR=3.13, 95% CI 2.27-4.17, p<.001) or Medicare (OR=1.67, 95% CI 1.11-2.5, p=.01). Patients 65 or older (OR=.48, 95% CI .36-.65, p<.001), pts of Asian/Pacific Islander race (OR=.24, 95% CI .12-.5, p<.001), and pts of Hispanic ethnicity (OR=.42, 95% CI .26-.68, p<.001) were less likely to report C/R smoking. Conclusions: A high proportion (17.4%) of trial enrollees report C/R smoking. These pts are more likely to be male, younger, White, non-Hispanic ethnicity, Black, or from medically vulnerable populations (pts from areas of greater deprivation or with Medicaid or no insurance). Accurate recording of pt smoking status in clinical trials will advance identification of disparate associations. Future studies comparing outcomes and toxicities for clinical trial pts reporting C/R smoking vs others are warranted.