Effectiveness of a Sedentary Behaviour Intervention as a Personalised Secondary Prevention Strategy (SIT LESS) for patients with coronary artery disease: primary outcomes of the SIT LESS trial

Type of funding sources: Foundation. Main funding source(s): Dutch Heart Foundation.

High levels of time spent sedentary are associated with increased risk of cardiovascular disease morbidity and mortality, even after accounting for traditional risk factors. A sedentary lifestyle is highly prevalent among patients with coronary artery disease (CAD).

This clinical trial aimed to determine whether a multicomponent, hybrid (center- and home-based), sedentary behaviour change intervention as a personalized secondary prevention strategy (SIT LESS) reduces daily sedentary time among patients with CAD participating in cardiac rehabilitation.

Patients were randomised to usual care (n=104) or SIT LESS (n=108). Both groups received a comprehensive 12-week centre-based cardiac rehabilitation programme with face-to-face consultations and supervised exercise sessions, whereas SIT LESS participants additionally received a 12-week, nurse-delivered, hybrid behaviour change intervention in combination with an activity tracker connected to a smartphone application. Primary outcome was the change in objectively measured sedentary time between pre- to post-rehabilitation.

Patients (77% male) were 63±10 years and primarily diagnosed with myocardial infarction (78%). Sedentary time decreased in SIT LESS (−1.6 [−2.1 to −1.1] hours/day) and controls (−1.2 [ ─1.7 to −0.8]), but between group differences did not reach statistical significance (─0.4 [─1.0 to 0.3]) hours/day, Central Figure). The post-rehabilitation proportion of patients with a sedentary time above the upper limit of normal (≥9.5 hours/day) was significantly lower in SIT LESS versus controls (48% versus 72%, baseline-adjusted odds-ratio 0.4 (0.2-0.8)). No differences were observed in the other predefined secondary outcomes.

Among patients with coronary artery disease participating in cardiac rehabilitation, SIT LESS did not induce significantly greater reductions in sedentary time compared to controls, but delivery was feasible and a reduced odds of a sedentary time ≥9.5 hours/day was observed.