Table 1.

Intervention components for intervention and control arms

Module	Dosage & Delivery	Components	Couple-based Intervention Group	Individual-based Control Group	BCT a
Health Education & Training	4 weekly 2-h sessions, delivered by two care managers in class.	Group Education	T2DM patients & their spouses	T2DM patients	Comparison of behavior
		1. Diabetes & Complication
		Understand diabetes Hypoglycemia Glucose monitoring	Couple-level discussion & practice	Patient-level discussion & practice	Shaping knowledge
		2. Healthy Diet
		Diabetes nutrition Food label Dietary plan	Collaborative- management Collective behavior goal setting	Self-management Individual behavior goal setting	Social support b Goals & planning
		3. Medication
		Taking (multi-) medication Medication adherence Foot care	Couples identify barriers & solutions collaboratively;	Patients identify barriers & solutions themselves;	Antecedents Association
		4. Being Active
		Exercise recommendations Risk management Exercise goal & plan	Use “we will” in these activities.	Use “I will” in these activities.	Goals & planning
Behavior Change Booster	2 months of weekly tailored call	Interactive call tailored to participant’s behavior change barriers, with call frequency varied by their progress.	Deliver to the couple	Deliver to the patient only	Repetition & substitution Feedback & monitoring
Behavior Change Incentive	Throughout intervention	Vouchers gain or lose by fulfilling or failing management tasks, with group ranking.	Incentives for individual & couple performance	Incentives for individual performance only	Reward & threat

^a BCT: behavior change technique was defined by Behavior Change Techniques Taxonomy Volume 1 [30]

^b BCT for couple-based intervention only