New atherogenic index for the prediction of carotid atherosclerosis based on the non-ultrasensitive c-reactive protein/HDL ratio

Abstract

Introduction: Current guidelines recommend cardiovascular risk assessment as a preventive measure for cardiovascular diseases, whose fundamental etiology is arteriosclerosis. One of the tools used to estimate risk in clinical practice are atherogenic indices (AI), ratios between lipid fractions with well-established reference ranges. Despite its widespread use, there is still limited information on its clinical utility. In recent years, some research has reinforced the role of inflammation in the etiology and chronicity of the atherosclerotic process. The inclusion of inflammatory parameters in the AI calculation could improve its diagnostic performance in the detection of arteriosclerosis. We sought to evaluate a new AI as a ratio between C-reactive protein (CRP) values and high-density lipoprotein cholesterol (HDL) values.

Methods: A total of 282 asymptomatic patients with no history of cardiovascular disease were included in the study. Laboratory tests with lipid profile and CRP, and carotid ultrasound to assess the presence of atheromatosis were performed in all of them. The new AI is established as the ratio between non-ultrasensitive CRP value in mg/dL (multiplied by 100) and HDL value in mg/dL. It was compared with the Castelli I and II indices, and the plasma atherogenic index. The optimal cut-off point of the new AI was value=1 as determined by ROC curve, with an area under the curve of 0.678 (95% CI 0.60-0.75; p<0.001).

Results: Mean age of patients was 60.4±14.5 years. A total of 118 patients (41.8% of total) had carotid arteriosclerosis. When evaluating the diagnostic performance of different AIs, we found that CRP·100/HDL ratio showed the highest values of sensitivity and positive predictive value (0.73 and 0.68, respectively) compared to the Castelli I and II indices, and the plasma atherogenic index. It was also the only predictor of carotid atheromatosis both when considering its values quantitatively (with OR 1.4 [95% CI 1.1-1.7]; p=0.005), and qualitatively (with OR 2.9 [95% CI 1.5-5.5]; p<0.001) in patients with a CRP·100/HDL ratio>1.

Conclusions: The new PCR·100/HDL index showed the best diagnostic performance in the detection of carotid atheromatosis compared to other classic AIs in this Spanish population of asymptomatic patients.

Keywords: Arterioesclerosis; Atherogenic index; Atherosclerosis; C-reactive protein; Carotid ultrasound; Ecografía de troncos supraaórticos; High-density lipoprotein; Lipoproteínas de alta densidad; Proteína C reactiva; Índice aterogénico.