A cardiac-rehab behaviour intervention to reduce sedentary time in coronary artery disease patients: the SIT LESS study

This data sharing collection contains materials used and data collected as part of the ‘SIT LESS (Sedentary behaviour IntervenTion as a personaLisEd Secondary prevention Strategy) study’. Background: As high sedentary times (ST) are highly prevalent in patients with coronary artery disease (CAD), we developed and evaluated the 12-week, hybrid behavioural change intervention SIT LESS. We examined the immediate and medium-term effect of the SIT LESS intervention on changes in ST among CAD patients enrolled in cardiac rehabilitation (CR). Methods: CAD patients participating in CR at 2 regional hospitals were included in this randomized controlled trial (1:1, stratified for gender and hospital). The control group received CR, whereas SIT LESS participants additionally received a 12-week hybrid behaviour change intervention. The primary outcome was the change in accelerometer-derived ST from pre-CR to post-CR and 3 months post-CR. Secondary outcomes included changes in ST and physical activity characteristics, subjective outcomes, and cardiovascular risk factors. A baseline constrained linear mixed-model was used. Results: Participants (23% female; SIT LESS: n = 108, control: n = 104) were 63 ± 10 years. Greater ST reductions were found for SIT LESS compared to control post-CR (-1.7 (95% confidence interval (CI): -2.0; -1.4) versus - 1.1 (95% CI: -1.4; -0.8) h/day, pinteraction=0.009), but not at 3 months post-CR (pinteraction=0.61). Besides, larger light-intensity physical activity (LIPA) increases were found for SIT LESS compared to control post-CR (+ 1.4 (95% CI: +1.2; +1.6) versus + 1.0 (95% CI: +0.8; +1.3) h/day, pinteraction=0.020). Changes in other secondary outcomes did not differ among groups. Conclusion: SIT LESS transiently reduced ST and increased LIPA, but group differences were no longer significant 3 months post-CR. These findings highlight the challenge to induce sustainable behaviour changes in CAD patients without any continued support.