Abstract 43: Adherence to a Lifestyle Intervention Program Not Improved by Visual Knowledge of Carotid Intima Atherosclerosis

Background: The use of carotid intima media thickness (CIMT) ultrasound to identify subclinical atherosclerosis is widespread, but few studies examine its influence on patient behavior. This randomized, double-blinded clinical trial examined, in participants with ≥ 2 cardiovascular disease (CVD) risk factors and subclinical atherosclerosis, the use of CIMT ultrasound images to motivate adherence to a lifestyle change program. Methods: Participants were randomized into either the intervention group [receive CIMT results weekly (R-CIMT)] or control group [CIMT results withheld (W-CIMT)]. All participants received the 12-week lifestyle program (Mediterranean diet, aerobic exercise, group support). We determined the overall change in program adherence from baseline to week 12 using an ANCOVA model with CIMT group and gender as factors and age as the covariate. Percent adherence was calculated as a composite measure of diet and exercise adherence at baseline and 12 weeks: [Diet adherence = (Mediterranean Diet Score/14) X 100% + Exercise adherence = (weekly exercise time/180) X 100%]/2 where exercise adherence was capped at 100%. The R-CIMT group received a CIMT tutorial explaining results and associated increased CVD risk. Comprehension was assessed by a knowledge test at week 12 in the R-CIMT group only. Baseline motivation was assessed to determine its predictive ability of adherence when added to group assignment in a standard regression model. Results: 142 participants (R-CIMT n=69; W-CIMT n=73) completed the study; mean age = 55 ± 10 yrs; 64% women (n=91); 45% black (n=64). Several demographic differences were seen between groups: R-CIMT group was older (57 vs. 53; p=0.02) and had a higher % female [73 (51 or 79) vs. 55 (40 of 73); p=0.02]. When comparing R-CIMT vs. W-CIMT group assignment, no difference was detected in overall % change in adherence respectively (19.6 ± 24.3 vs. 22.6 ± 24.2; p=0.52). Baseline motivation was similar in both groups and not predictive of change in adherence when added to group assignment (p=0.68). Median knowledge test score = 90% (80,100) in responding completers (80%; 55 of 69). Conclusions: Although the presence of subclinical atherosclerosis increased participant knowledge of their increased CVD risk, it did not act as a motivator in these participants to improve lifestyle change adherence more than those in the control group.