Basic demographics, clinical data and laboratory assays
A total of 216 patients were included in the AMI group, 153 patients were included in the UA group, and 103 healthy subjects were included in the control group. Of the 472 participants who qualified for inclusion in this study, 314 were females and 158 were males. Significant differences were observed in gender, history of smoking, diabetes mellitus, levels of glucose, sdLDL-C, LDL-C, TC, and HDL between the AMI group and the control group (P < 0.05). There were significant differences in gender, hypertension, diabetes mellitus, and history of smoking between the UAP group and the control group. However, the levels of sdLDL-C were not significantly different between the UAP group and the control group. Detailed statistics on basic demographics, clinical data and laboratory assay results for all participants are shown in Table 1.
Table 1
Clinical and laboratory characteristics in all subjects
Variables | AMI (n = 216) | UA (n = 153) | Control (n = l03) | Pvalue |
Age (years) | 57.61 ± 10.9 | 60.47 ± 8.5 | 57.9 ± 9.4 | 0.019 |
Gender | 173 (80.1)** | 102 (66.7)** | 39 (37.9) | 0.003 |
Hypertension (%) | 110 (51.0) | 90 (58.8) * | 42 (40.8) | 0.123 |
Diabetes mellitus (%) | 38 (17.6)** | 36 (23.4) ** | 5 (4.9) | 0.164 |
History of smoking (%) | 130 (60.2)** | 65 (42.2) ** | 23 (22.3) | 0.001 |
Family history of CAD (%) | 23 (10.6) | 6 (3.9) | 7 (6.8) | 0.019 |
sdLDL-C(mg/dL) | 18 (9,34.75)** | 12 (6,22) | 12 (7,23) | < 0.001 |
LDL-C (mmol/L) | 2.62 (1.92,3.25) ** | 2.13 (1.52,2.79)* | 2.37 (1.68,2.98) | < 0.002 |
TC (mmol/L) | 4.46 (3.8,5.1)* | 4.06 (3.42,4.87)* | 4.21 (3.67,4.84) | < 0.003 |
TG (mmol/L) | 1.31 (0.8,2.11) | 1.57 (1.03,2.45) | 1.52 (0.97,2.21) | < 0.004 |
HDL (mmol/L) | 1.04 (0.9,1.26)* | 1.01 (0.9,1.21)** | 1.07 (0.96,1.28) | 0.116 |
GLU (mmol/L) | 6.63 (5.51,8.71) ** | 6.19 (5.19,7.61)* | 5.82 (5.13,7.03) | < 0.001 |
Comparison the control group,*p < 0.05༌**p < 0.001 |
Comparison Of The Sdldl-c Subgroups In Different Groups
A comparison of the sdLDL-C subgroups in the different groups is shown in Table 2. The levels of LDL3-7 were significantly different among the three groups (P < 0.05). Notably, the serum levels of LDL3 and LDL4 in the AMI group were higher than those in the other groups. However, there were no significant differences in the levels of LDL-1 or LDL-2 between the different groups.
Table 2
LDL subtractions in difference group
LDLsubclasses | AMI (n = 216) | UA (n = 153) | Control (n = l03) | P-value |
LDL-1(mg/dL) | 20 (11.3,37.8) | 22.5 (16,34) | 24 (17,34) | 0.258 |
LDL-2(mg/dL) | 24.5 (15,39) | 21 (16,31.25) | 24 (16,32) | 0.245 |
LDL-3(mg/dL) | 14 (8,21) | 9 (4,15.5) | 10 (6,16) | < 0.001 |
LDL-4(mg/dL) | 4 (1,10) | 2 (0,4) | 2 (0,6) | < 0.001 |
LDL-5(mg/dL) | 0 (0,3) | 0 (0,0) | 0 (0,0) | < 0.001 |
LDL-6(mg/dL) | 0 (0,0) | 0 (0,0) | 0 (0,0) | < 0.001 |
LDL-7(mg/dL) | 0 (0,0) | 0 (0,0) | 0 (0,0) | 0.018 |
Correlations Of Clinical Characteristics And Gensini Scores
Spearman correlation coefficients were calculated to determine the correlation between the clinical characteristics and Gensini scores of the three groups, and a heatmap was drawn accordingly (Fig. 1). There were significant positive correlations between the Gensini score and several variables, including hypertension and levels of glucose, sdLDL-C, TC, and LDL-C (r > 0.1, P < 0.001).
Correlation of the sdLDL-C level with other serum lipid parameters
As shown in Fig. 2 and Table 3, the Spearman correlation coefficient was used to assess the correlations of the sdLDL-C concentration with serum lipids. Significant positive correlations were observed between the sdLDL-C level and serum lipids, including TC, TG, LDL-C and HDL-C levels. The sdLDL-C level was found to be positively correlated with TC, TG and LDL-C levels (r = 0.251, P < 0.001, r = 0.144, P = 0.008, r = 0.351, P < 0.001). There was a significant inverse correlation between sdLDL-C and HDL levels (r=-0.248, P < 0.001).
Table 3
Correlation of sdLDL-C level with serum lipids
Serum lipids | sdLDL-C |
| Pearson R | P-value |
TC | 0.251 | < 0.001 |
TG | 0.144 | 0.008 |
LDL-C | 0.351 | < 0.001 |
HDL | -0.248 | < 0.001 |
Comparison of sdLDL levels between the AMI and control group in participants with normal LDL-C
As shown in Table 4 and Fig. 3, in participants with a normal LDL-C (LDL-C ≤ 3.36mmol/L), the sdLDL-C level in the AMI group was significantly higher than that in the control group (P < 0.001).
Table 4
Comparison of sdLDL levels between the AMI and control group in participants with normal LDL-C (LDL-C ≤ 3.36mmol/L)
| AMI (n = 137) | Control (n = 112) | Pvalue |
sdLDL-C | 18 (10.5,41) | 14 (7,24) | 0.001 |
Exploration of risk factors for AMI by ROC curve analysis
ROC curve analysis was performed to evaluate the predictive value of sdLDL-C and other serum lipids, including LDL-C and TC, and the results are depicted in Fig. 4. The results indicated that sdLDL-C presented with a higher AUC than other serum lipid parameters [AUC (95% CI): sdLDL‐C, 0.666]. The ROC curve of LDL-C and TC levels for AMI was 0.621 and 0.576, respectively. The best cut-off value of sdLDL-C was 24.5 mg/dL, with a sensitivity and specificity of 47.2% and 79.6%, respectively.
Multivariate Logistic Regression Analysis Of Risk Factors For Ami
The independent variables with a univariate analysis result of P < 0.05 were included in the multivariate logistic regression analysis. Eight variables were included in the multivariate analysis, including gender, diabetes mellitus, history of smoking, and levels of sdLDL-C, TC, HDL-C, LDL-C, and glucose, and the results are shown in Table 5. The present study findings indicated that increased sdLDL-C levels were an independent risk factor for AMI [OR (95% CI): 1.029, 1.01-1.048, P = 0.003]. In addition, there were variables deemed to be risk factors with an odds ratio (OR) greater than 1 and P-values less than 0.05, including gender, LDL-C level and glucose level. No significant differences existed between AMI and other variables.
Table 5
Multivariable Logistic Regression Analysis of Risk Factors for AMI
Variable | OR Value | 95% CI | P value |
sdLDL-C | 1.029 | 1.010–1.048 | 0.002 * |
TC | 0.689 | 0.406–1.171 | 0.169 |
HDL-C | 2.145 | 0.660–6.972 | 0.204 |
LDL-C | 2.521 | 1.436–4.424 | 0.001 * |
GLU | 1.486 | 1.268–1.742 | < 0.001 * |
Gender | 5.952 | 2.705–13.907 | < 0.001 * |
History of smoking | 2.089 | 0.976–4.471 | 0.058 |
sdLDL-C small dense Low density lipoprotein cholesterol, TC total cholesterol, HDL-C high-density lipoproteins cholesterol, LDL low-density lipoprotein, Glu glucose, OR odds ratio, CI confidence interval |
*p < 0.05 |
A logistic regression model was performed to assess the AMI and effectively distinguish high-risk from low-risk patients with cardiovascular diseases, with an AUC of 0.868 (Fig. 5). Conventional cardiovascular and lipid risk factors included gender, history of smoking, diabetes mellitus, and levels of glucose, sdLDL-C, TC, HDL-C, and LDL-C.