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

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.