Mobile phone-based smoking-cessation intervention in patients with chronic diseases in China: a Sequential Multiple Assignment Randomized Trial (SMART)

Abstract Introduction Mobile phone-based interventions show promise for smoking cessation but often face low engagement. This study assessed the feasibility and preliminary effectiveness of a 2-phase, multi-component mobile phone-based smoking cessation intervention for patients with chronic diseases. Methods This Sequential Multiple Assignment Randomized Trial (SMART) recruited smokers with chronic diseases from hospitals in Zhuhai, China. Participants received brief cessation advice and were randomized to personalized chat support (PCS, n=64) or group chat support (GCS, n=64) for 1 month. At 1-month, PCS non-responders (continuing smokers) were re-randomized to receive either multi-component optional support (MOS) or continued PCS for 2 months. GCS non-responders were re-randomized to receive PCS or continued GCS. Responders continued with their initial intervention for 2 months. Feasibility outcomes included eligibility, participation, retention, intervention engagement, and satisfaction. Preliminary effectiveness was assessed by abstinence rates among non-responders. Results Of 160 screened, 128 (all male, 46.1% aged≤39 years) participated. At 1-month, 51 and 53 non-responded to PCS and GCS, respectively. Of them, 26 were re-randomized to receive PCS-MOS and 26 to receive GCS-PCS. At 6-month, PCS-MOS showed a non-significant higher validated abstinence rate compared to PCS alone (11.5% vs. 4.2%, odds ratio [OR] 3.13, 95%CI 0.30-32.31, P=0.34), GCS-PCS showed a non-significant lower validated abstinence rate compared to GCS (0% vs. 11.1%, OR 0.50, 95%CI 0.15-1.67, P=0.26). Conclusions This trial showed the feasibility of leveraging hospital visits as teachable opportunities and integrating mobile phone-based smoking cessation support into chronic disease management in China. Optional treatments alongside mobile support showed preliminary effectiveness.