Prognostic Value of Abdominal Aortic Calcification: A Systematic Review and Meta-Analysis of Observational Studies

Abstract

Background The prognostic importance of abdominal aortic calcification (AAC) viewed on noninvasive imaging modalities remains uncertain. Methods and Results We searched electronic databases (MEDLINE and Embase) until March 2018. Multiple reviewers identified prospective studies reporting AAC and incident cardiovascular events or all-cause mortality. Two independent reviewers assessed eligibility and risk of bias and extracted data. Summary risk ratios (RRs) were estimated using random-effects models comparing the higher AAC groups combined (any or more advanced AAC) to the lowest reported AAC group. We identified 52 studies (46 cohorts, 36 092 participants); only studies of patients with chronic kidney disease (57%) and the general older-elderly (median, 68 years; range, 60-80 years) populations (26%) had sufficient data to meta-analyze. People with any or more advanced AAC had higher risk of cardiovascular events (RR, 1.83; 95% CI, 1.40-2.39), fatal cardiovascular events (RR, 1.85; 95% CI, 1.44-2.39), and all-cause mortality (RR, 1.98; 95% CI, 1.55-2.53). Patients with chronic kidney disease with any or more advanced AAC had a higher risk of cardiovascular events (RR, 3.47; 95% CI, 2.21-5.45), fatal cardiovascular events (RR, 3.68; 95% CI, 2.32-5.84), and all-cause mortality (RR, 2.40; 95% CI, 1.95-2.97). Conclusions Higher-risk populations, such as the elderly and those with chronic kidney disease with AAC have substantially greater risk of future cardiovascular events and poorer prognosis. Providing information on AAC may help clinicians understand and manage patients' cardiovascular risk better.

Keywords: abdominal aortic calcification; all‐cause mortality; cardiovascular events and deaths; chronic kidney disease; general population.

Figure 1. Study flow.

AAC indicates abdominal aortic calcification; and CV, cardiovascular.

Figure 2. Association between abdominal aortic calcification (AAC) and cardiovascular disease events (CVD, A and B), fatal cardiovascular events (CV, C and D) and all‐cause mortality (E and F) in cohorts from the general population (left panels) or patients with chronic kidney disease (CKD) (right panels).

Figure 3. Summary ROC (sROC) showing the point estimate (area under the curve [AUC]) for the diagnostic accuracy of AAC to identify people at risk of cardiovascular events (A and B), fatal cardiovascular events (C and D) and all‐cause mortality (E and F) in cohorts from the general population (left panels) or patients with chronic kidney disease (CKD) (right panels).

Graphs are based on the paired sensitivity and false‐positive rates plotted together with a confidence region (circled area). Each triangle represents the summary sensitivity and false positive rate from a single cohort.

Figure 4. Cardiovascular risk factor adjusted association between abdominal aortic calcification (AAC) and cardiovascular disease events (CVD) (A), fatal cardiovascular events (B), all‐cause mortality (C), coronary heart disease events (D), and cerebrovascular disease events (E) in cohorts from the general population.

Adjusted measures of risk only presented in; F indicates female only; H, high AAC vs none/less advanced; L, low AAC vs none/less advanced; and M, male only.