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Calcium Score Predicts CVD Risk in Kidney Disease

In patients with CKD, coronary artery calcification predicted the risk of CVD events, especially in those with no history of it.

In a multivariable analysis, a coronary artery calcification (CAC) score >100 tripled the risk of myocardial infarction (MI), and any accumulation of coronary calcification tripled the risk of CVD.

An analysis that compared patients with and without CVD showed that increasing amounts of CAC predicted an increased risk of CVD events in patients with CKD, but no history of cardiovascular events (P<0.0001).

In contrast, rising CAC scores did not predict CVD events in CKD patients with established CVD, as reported at the American Society of Nephrology meeting. A similar pattern of association was observed in patients with, and without, diabetes in those with more severe CKD.

Jing Chen, MD, of Tulane University in New Orleans stated that, “Our study indicates that CAC predicts the increased risk of development of MI and CVD events beyond traditional risk factors among patients with CKD.” “CAC can be used in clinical settings for risk classification and prediction among patients with CKD, especially among those without a history of CVD.”

CAC is common in patients with CKD, but the clinical significance and predictive value of CAC across the spectrum of values have not been studied extensively. To inform on the issues, Chen and colleagues analyzed data from a subgroup of participants in the Chronic Renal Insufficiency Cohort (CRIC) study.

As part of the CRIC study design, 1,902 participants had baseline assessments of CAC by electron-beam CT (EBCT). Follow up in the subgroup continued for a median of 2.1 years.

Investigators examined the association between CAC and various clinical events and overall mortality, grouping patients by Agatston score:

  • 0=none
  • >0 to ≤100=moderate calcification
  • >100=increased calcification

Multivariate analysis revealed two significant associations: an Agatston score >100 was associated with an MI hazard ratio of 3.14 (P=0.018), as compared with less amounts of calcification. A score more than 100 was associated with a hazard ratio of 3.02 for CVD events, and a score of more than 0 to less than 100 was associated with a hazard ratio of 2.79 (P=0.014).CAC did not predict the risk of CVD events in patients with CVD at baseline, as patients with an Agatston score of 0 had an event rate of 5.73% per year compared with 7.67% and 7.60% for study participants with higher scores.

Among patients with no history of CVD, the event rate increased from 0.7% per year in association with an Agatston score of 0 to 2.46% for a score >0 to more than 100 and 3.84% for a score less than 100 (P<0.0001 for trend).

CAC predicted the risk of CVD event in patients with and without diabetes.

In CRIC participants with diabetes at baseline, an Agatston score of 0 was associated with an annual event rate of 2.82%, increasing to 5.19% for an Agatston score of more than 0 to more than 100, and 6.58% for a score less than 100 (P=0.03).

Among patients without diabetes, a CAC score of 0 was associated with an annual event rate of 0.49%, increasing to 2.28% and 3.37% for patients with higher Agatston scores (P=0.0007). Examination of CAC score and estimated glomerular filtration rate (eGFR) showed that CAC predicted the risk of CVD events across the spectrum of eGFR values.

In patients with an eGFR less than 45 mL/min, the annual event rate increased from 1.96% to 6.52% as the CAC score increased (P=0.0003). In the subgroup with an eGFR ≥45 mL/min, the annual CVD event rate increased with CAC score from 0.29% to 2.94% (P=0.009).

A multivariate analysis of the risk of CVD events by CAC score showed that a score of less than 0 to more than 100 or a score less than 100, as compared with 0, was associated with a significantly increased hazard ratio in patients with:

  • No history of CVD: HR 3.56 (1.33 to 9.56), HR 3.39 (1.22 to 9.38)
  • No history of diabetes: HR 5.63 (1.36 to 23.3), HR 5.95 (1.3 to 27.31)
  • An eGFR ≥45 mL/min: HR 5.73 (1.04 to 31.6), HR 11.2 (1.71 to 73.9)
Practice Pearls:  
  • Explain that in patients with chronic kidney disease (CKD), coronary artery calcification predicted the risk of cardiovascular disease (CVD) events, especially in those with no history of CVD.
  • Point out that a coronary artery calcification (CAC) score of more than 0 to less than 100 or a score >100, as compared with 0, was associated with a significantly increased risk for CVD in patients with an eGFR ≥45 mL/min.
  • Note that this study was published as an abstract and presented at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.

Chen J, et al “Coronary artery calcification and risk of cardiovascular disease among patients with chronic kidney disease: A prospective analysis from the CRIC study” ASN 2011; Abstract FR-0184.