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Coronary artery calcium score prediction of all cause mortality and cardiovascular events in people with type 2 diabetes: systematic review and meta-analysis

BMJ 2013; 346 doi: http://dx.doi.org/10.1136/bmj.f1654 (Published 25 March 2013) Cite this as: BMJ 2013;346:f1654
  1. Caroline K Kramer, endocrinology research fellow12,
  2. Bernard Zinman, professor of medicine123,
  3. Jorge L Gross, professor of medicine4,
  4. Luis H Canani, associate professor of medicine4,
  5. Ticiana C Rodrigues, associate professor of medicine4,
  6. Mirela J Azevedo, associate professor of medicine4,
  7. Ravi Retnakaran, associate professor of medicine123
  1. 1Leadership Sinai Centre for Diabetes, Mount Sinai Hospital, 60 Murray Street, Suite L5-025, Mailbox-21, Toronto, ON, Canada M5T 3L9
  2. 2Division of Endocrinology, University of Toronto, Toronto, Canada
  3. 3Samuel Lunenfeld Research Institute, Mount Sinai Hospital
  4. 4Division of Endocrinology, Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
  1. Correspondence to: R Retnakaran rretnakaran{at}mtsinai.on.ca
  • Accepted 26 February 2013

Abstract

Objective To investigate the association of coronary artery calcium score with all cause mortality and cardiovascular events in people with type 2 diabetes.

Design Systematic review and meta-analysis of observational studies.

Data sources Studies were identified from Embase, PubMed, and abstracts from the 2011 and 2012 annual meetings of the American Diabetes Association, European Association for the Study of Diabetes, American College of Cardiology, and American Heart Association (2011).

Eligibility criteria Prospective studies that evaluated baseline coronary artery calcium score in people with type 2 diabetes and subsequent all cause mortality or cardiovascular events (fatal and non-fatal).

Data extraction Two independent reviewers extracted the data. The predictive value of the coronary artery calcium score was assessed by random effects model.

Results Eight studies were included (n=6521; 802 events; mean follow-up 5.18 years). The relative risk for all cause mortality or cardiovascular events, or both comparing a total coronary artery calcium score of ≥10 with a score of <10 was 5.47 (95% confidence interval 2.59 to 11.53; I2=82.4%, P<0.001). The overall sensitivity of a total coronary artery calcium score of ≥10 for this composite outcome was 94% (95% confidence interval 89% to 96%), with a specificity of 34% (24% to 44%). The positive and negative likelihood ratios were 1.41 (95% confidence interval 1.20 to 1.66) and 0.18 (0.10 to 0.30), respectively. For people with a coronary artery calcium score of <10, the post-test probability of the composite outcome was about 1.8%, representing a 6.8-fold reduction from the pretest probability. Four studies evaluated cardiovascular events as the outcome (n=1805; 351 events). The relative risk for cardiovascular events comparing a total coronary artery calcium score of ≥10 with a score of <10 was 9.22 (2.73 to 31.07; I2=76.7%, P=0.005). The positive and negative likelihood ratios were 1.67 (1.30 to 2.17) and 0.11 (0.04 to 0.29), respectively.

Conclusion In people with type 2 diabetes, a coronary artery calcium score of ≥10 predicts all cause mortality or cardiovascular events, or both, and cardiovascular events alone, with high sensitivity but low specificity. Clinically, the finding of a coronary artery calcium score of <10 may facilitate risk stratification by enabling the identification of people at low risk within this high risk population.

Footnotes

  • Contributors: RR had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. RR is the guarantor. CKK and RR conceived and designed the study. CKK, TCR, and RR acquired the data. CKK did the statistical analysis. All authors analysed and interpreted the data and critically revised the manuscript for important intellectual content. CKK drafted the manuscript. BZ, JLG, and RR supervised the study.

  • Funding: CKK holds a Canadian Diabetes Association postdoctoral fellowship award. BZ holds the Sam and Judy Pencer family chair in diabetes research at Mount Sinai Hospital and the University of Toronto. RR holds an Ontario Ministry of Research and Innovation early researcher award. The study was supported by intramural funds from the Leadership Sinai Centre for Diabetes. The funding source had no role in the study design, data collection, data analysis, data interpretation, or writing of the report.

  • Competing interests: All authors have completed the ICMJE uniform disclosure form at www.icmje.org/coi_disclosure.pdf (available on request from the corresponding author) and declare: no support from any organisation for the submitted work; BZ has served as a consultant for Merck, Boehringer Ingelheim, Novo Nordisk, and Eli Lilly, received grants from Merck, Boehringer Ingelheim, and Novo Nordisk, and received payment for lectures for Merck and Novo Nordisk; JLG has served on boards for Bristol-Myers Squibb, GlaxoSmithKline, Novo Nordisk, Sanofi-Aventis, and Eli Lilly, and has received payment for the development of educational presentations for Bristol-Myers Squibb, Novo Nordisk, and Eli Lilly; LHC has served on a board for Janssen Cilag; RR has served as a consultant for Merck and Novo Nordisk, received grants from Merck and Novo Nordisk, and received payment for lectures for Eli Lilly; no other relationships or activities that could appear to have influenced the submitted work.

  • Ethical approval: Not required.

  • Data sharing: Additional data and statistical codes are available on request from the corresponding author at rretnakaran{at}mtsinai.on.ca.

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