Role of abdominal aortic calcification score in predicting cardiovascular risk in the general population.

BACKGROUND

Abdominal aortic calcification (AAC) is closely related to cardiovascular disease. Although its clinical significances have primarily been investigated in patients with chronic kidney disease, its association with cardio-cerebrovascular mortality in the general middle-aged and elderly population has not been sufficiently investigated.

AIMS

To study the association of AAC and cardio-cerebrovascular mortality in both the entire general middle-aged and elderly populations and age subgroups.

METHODS

Data of participants of the National Health and Nutrition Examination Survey (NHANES) 2013-2014 were analyzed. This study included middle-aged and elderly (≥ 40 years old) individuals who underwent dual-energy X-ray absorptiometry. The severity of AAC was assessed by an AAC scoring system (AAC score) with a maximum possible value of 24. Participants were tracked for survival status and major cause of death till 31st December 2019. This study utilized AAC score = 6 as the optimal cut-off according to Harrell's c statistic. Based on AAC scores, participants were trichotomized (0, 0-6, and ≥ 6). Groupwise survival curves and cumulative incidence functions were plotted to reveal the association of AAC and cardio-cerebrovascular mortality. Given results under trichotomization, combination of participants with AAC scores 0 and 0-6 was conducted to reaffirm the association of AAC and adverse prognosis.

RESULTS

Correlation between increased AAC score and poorer survival, higher cumulative incidence of events was revealed. Cox models identified AAC score ≥ 6 as an independent risk factor of cardio-cerebrovascular mortality (AAC score ≥ 6 vs. AAC score = 0: Hazard ratio: 2.38, P = 0.008) after adjusting for cardiovascular risk factors. Results remained significant after regrouping (AAC score ≥ 6 vs. AAC score < 6: Hazard ratio: 2.06, P = 0.016). Subgroup analysis provided no evidence of unparallel change in hazard for the same amount of increase in AAC score among middle-aged (40-65 years old) and elderly (≥ 65 years old) individuals.

CONCLUSIONS

AAC score ≥ 6 independently indicate increased risk of cardio-cerebrovascular death and would be effective in risk stratification among the general middle-aged and elderly population in clinical practice.