Serum Calcification Propensity and Coronary Artery Calcification Among Patients With CKD: The CRIC (Chronic Renal Insufficiency Cohort) Study

Rationale & Objective Coronary artery calcification (CAC) is prevalent among patients with chronic kidney disease (CKD) and increases risks for cardiovascular disease events and mortality. We hypothesized that a novel serum measure of calcification propensity is associated with CAC among patients with CKD stages 2 to 4. Study Design Prospective cohort study. Setting & Participants Participants from the Chronic Renal Insufficiency Cohort (CRIC) Study with baseline (n=1,274) and follow-up (n=780) CAC measurements. Predictors Calcification propensity, quantified as transformation time (T 50 ) from primary to secondary calciprotein particles, with lower T 50 corresponding to higher calcification propensity. Covariates included age, sex, race/ethnicity, clinical site, estimated glomerular filtration rate, proteinuria, diabetes, systolic blood pressure, number of antihypertensive medications, current smoking, history of cardiovascular disease, total cholesterol level, and use of statin medications. Outcomes CAC prevalence, severity, incidence, and progression. Analytical Approach Multivariable-adjusted generalized linear models. Results At baseline, 824 (65%) participants had prevalent CAC. After multivariable adjustment, T 50 was not associated with CAC prevalence but was significantly associated with greater CAC severity among participants with prevalent CAC: 1-SD lower T 50 was associated with 21% (95% CI, 6%-38%) greater CAC severity. Among 780 participants followed up an average of 3 years later, 65 (20%) without baseline CAC developed incident CAC, while 89 (19%) with baseline CAC had progression, defined as annual increase≥100 Agatston units. After multivariable adjustment, T 50 was not associated with incident CAC but was significantly associated with CAC progression: 1-SD lower T 50 was associated with 28% (95% CI, 7%-53%) higher risk for CAC progression. Limitations Potential selection bias in follow-up analyses; inability to distinguish intimal from medial calcification. Conclusions Among patients with CKD stages 2 to 4, higher serum calcification propensity is associated with more severe CAC and CAC progression.