Introduction:
Carotid intima media thickness (CIMT) ultrasound is a known surrogate marker of atherosclerosis but few studies examine its influence on patient behavior. Motivation and self-efficacy (SE) are known predictors of health behavior change. This randomized, double-blind trial examined 1) use of CIMT images plus associated CVD risk to motivate adherence, and 2) the predictive ability of motivation and SE on adherence change.
Methods:
Patients with ≥ 2 cardiovascular disease (CVD) risk factors and subclinical atherosclerosis were assigned to either the intervention group [receive results weekly (R-CIMT)] or control group [withhold results (W-CIMT)]. All patients received a 12-week lifestyle program (Mediterranean diet, aerobic exercise, group support). Overall change in adherence from baseline to week 12 was determined using an ANCOVA model where % adherence was a composite measure of diet and exercise adherence. Initial motivation plus exercise and nutrition SE were assessed to determine their predictive ability of adherence in a standard regression model.
Results:
166 patients randomized; 161 (R-CIMT n=81; W-CIMT n=80) eligible for intention-to-treat analysis. Patients were middle age (mean age = 54 ± 11 yrs), 62% (100 or 161) women, 48% (77 of 161) black. Baseline group differences: W-CIMT group was younger (52 vs 55 yrs; p=0.05), had a lower systolic blood pressure (120 vs 125; p=0.01), lower % family history of CVD (49 vs 65; p=0.03). In comparing R-CIMT vs W-CIMT groups, no difference was detected in overall % adherence change (16.4 ± 25.6 vs 19.8 ± 25.4; p=0.39). Initial motivation and SE measures were not predictive of change in adherence when added to group assignment (see Table).
Conclusions:
CIMT evidence of subclinical atherosclerosis increased participant CVD risk awareness but did not translate into actionable healthy behavior changes beyond those in the control group. Neither exercise nor dietary adherence was affected by initial motivation or self-efficacy when added to CIMT risk awareness.
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