ABC | Volume 114, Nº3, March 2020

Original Article Kurmus et al. Discordance of lipoproteins and CAD severity Arq Bras Cardiol. 2020; 114(3):469-475 Figure 1 – Scatterplots and prevalence of discordance and concordance defined according to median values of LDL-C and non-HDL-C. LDL-C: low-density lipoprotein cholesterol; Non-HDL-C: non-high-density lipoprotein cholesterol. 450.00 350.00 250.00 150.00 50.00 .00 .00 400.00 300.00 300.00 200.00 200.00 100.00 100.00 non HDL-c (mg/dL) LDL-c (mg/dL) Discordant Discordant Concordant Concordant r: 0.865 p < 0.001 severe coronary stenosis. 28 In a study by Onat et al., 29 LDL-C was not a predictor of new-onset coronary heart disease. 29 In two studies evaluating Gensini score and LDL-C relationship, LDL-C showed no significant difference when compared to high and low Gensini scores. 30,31 In our study, LDL-C was not correlated to Gensini or SYNTAX scores. Non‑HDL-C was found to be higher in patients with a Gensini score of 50 or greater than patients with a Gensini score of less than 50. 30 There was a weak correlation (r = 0.113, p < 0.001) between non-HDL-C and Gensini score in a study by Zhang et al. 8 In our study, the proportion of patients with high SYNTAX scores and high Gensini scores was low. Lack of association between CAD severity and non-HDL-C may have resulted from the relatively limited number of patients with severe CAD in our population. There is a limited number of studies that evaluate the effect of discordance of LDL-C and non-HDL-C on coronary atherosclerosis severity. It was found that Gensini score was overestimated among patients with LDL-C greater than or equal to the median and non-HDL-C below the median. 8 Shiiba et al. 32 assessed the relationship between discordance and the mid-term outcome of coronary stent implantation. It was found that 3-vessel disease or left main tract disease did not differ among discordant and concordant groups, and discordance between LDL-C and non-HDL-C levels did not predict major adverse cardiovascular events after stent implantation. 32 We assessed CAD severity by Gensini score and complexity by SYNTAX score, and these did not differ between discordant and concordant groups in our study. Study limitations This study has several limitations. It has, for example, a retrospective design, which paves the way for the possibility of bias from unmeasured cofounders. One third of patients were using statins and the lack of association between discordance and CAD severity may have stemed from it. In addition, information about doses, species and duration of statin treatment were lacking. There is no absolute definition and standard cut-off values for the discordance of LDL-C and non-HDL-C. We used median values for our study population. Therefore, further large-scale prospective studies would be required to validate our results. Conclusion While discordance was present between LDL-C and non‑HDL-C (15% of patients), there is no difference regarding CAD severity and complexity between discordant and concordant groups. But the patients with LDL-C < median and non-HDL-C ≥ median present some high-risk features such as diabetes mellitus and higher triglyceride levels, and they may need further evaluation and close follow-up. 472