CT Angiography, Healthy Lifestyle Behaviors, and Preventive Therapy: A Nested Substudy of the SCOT-HEART 2 Randomized Clinical Trial.

Importance: Healthy lifestyles and uptake of primary preventive therapies for cardiovascular disease remain poor.

Objective: To determine the impact of coronary computed tomography (CT) angiography on healthy lifestyle behaviors, acceptance of recommended treatments, and modification of risk factors as compared with guideline-directed cardiovascular risk scoring.

Design, Setting, And Participants: This was a nested substudy conducted from September 2020 to August 2024 of a randomized clinical trial where participants underwent cardiovascular risk scoring or coronary CT angiography. Primary care-based screening took place in Scotland. Included in the analysis were asymptomatic individuals aged 40 to 70 years without known cardiovascular disease and with at least 1 cardiovascular risk factor. Study data were analyzed from August to September 2024.

Interventions: All participants received lifestyle advice with additional recommendations for moderate-intensity statin therapy if the 10-year cardiovascular risk was greater than or equal to 10% or combined antiplatelet and at least moderate-intensity statin therapies if coronary atherosclerosis was identified on CT angiography.

Main Outcomes And Measures: The composite primary outcome was compliance with the National Institute for Health and Care Excellence recommendations for diet, body mass index, smoking, and physical exercise at 6 months.

Results: Between September 2020 and January 2024, 400 participants were enrolled (median [IQR] age, 62 [56-65] years; 198 female [49.5%]; median [IQR] 10-year cardiovascular risk, 14% [9%-19%]) with 195 randomized to cardiovascular risk scoring and 205 to coronary CT angiography. At 6 months, those who underwent CT angiography were more likely to meet the primary composite end point (17% [33 of 194 participants] vs 6% [10 of 177 participants]; odds ratio, 3.42; 95% CI, 1.63-6.94; P < .001). Compared with cardiovascular risk scoring, fewer participants were recommended preventive therapy after CT angiography (51% [105 of 205 participants] vs 75% [147 of 195 participants]; P < .001), but acceptance of recommendations was higher (77% [81 of 105 participants] vs 46% [68 of 147 participants]; P < .001). This resulted in similar use of lipid-lowering therapy (44% [90 of 205 participants] vs 35% [69 of 195 participants]; OR, 1.43; 95% CI, 0.96-2.15; P = .08) and greater use of antiplatelet therapy in those randomized to CT angiography (40% [83 of 205 participants] vs 0.5% [1 of 195 participants]; P < .001). Participants randomized to coronary CT angiography had small incremental improvements in risk factors and 10-year cardiovascular risk, largely driven by those with CT-defined coronary atheroma.

Conclusions And Relevance: Results of this cohort study reveal that compared with cardiovascular risk scoring, coronary CT angiography was associated with modest improvements in healthier lifestyle behaviors, acceptance of recommended preventive therapy, and risk factor modification. Whether this strategy reduces coronary events remains to be established.