Natural History of Diabetic Coronary Atherosclerosis by Quantitative Measurement of Serial Coronary Computed Tomographic Angiography: Results of the PARADIGM Study.OBJECTIVES
 This study aimed to determine the rate and extent of plaque progression (PP), changes in plaque features, and clinical predictors of PP in patients with diabetes mellitus (DM).


 BACKGROUND
 The natural history of coronary PP in patients with DM is not well established.


 A total of 1,602 patients (age 61.3 ± 9.0 years; 60.3% men; median scan interval 3.8 years) who underwent serial coronary computed tomography angiography over a period of at least 24 months were enrolled and analyzed from the PARADIGM (Progression of Atherosclerotic Plaque Determined by Computed Tomographic Angiography Imaging) trial.  Study endpoints were changes in plaque features in diabetics with PP and risk factors for PP by serial coronary computed tomography angiography between patients with and without DM.  DM was an independent risk factor for PP (84.6%; 276 of 326 patients with PP) in multivariate analysis (odds ratio [OR]: 1.526; 95% confidence interval [CI]: 1.100 to 2.118; p = 0.011).  Independent risk factors for PP in patients with DM were male sex (OR: 1.485; 95% CI: 1.003 to 2.199; p = 0.048) and mean plaque burden at baseline ≥75% (OR: 3.121; 95% CI: 1.701 to 5.725; p ≤0.001).  After propensity matching, percent changes in overall plaque volume (30.3 ± 36.9% in patients without DM and 36.0 ± 29.7% in those with DM; p = 0.032) and necrotic core volume (-7.0 ± 35.8% in patients without DM and 21.5 ± 90.5% in those with DM; p = 0.007) were significantly greater in those with DM.  The frequency of spotty calcification, positive remodeling, and burden of low-attenuation plaque were significantly greater in patients with DM.


 CONCLUSIONS
 People with DM experience greater PP, particularly significantly greater progression in adverse plaque, than those without DM.  Male sex and mean plaque burden >75% at baseline were identified as independent risk factors for PP.
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