A total of 3684 participants were enrolled in this study, including 2220 CHD patients and 1464 non-CHD patients. Table 1 shows clinical characteristics and risk factors of all participants, including age, gender, glucose, HbA1c, blood-lipid indicators, Lp(a), hs-CRP, HCY and sdLDL-C. Levels of ApoB, LDL-C, hs-CRP, HCY, and sdLDL-C in CHD group were higher than those in non-CHD group. The CHD group had a significantly lower apoA1 and HDL-C levels compared with non-CHD group. There were no significant differences of other variables between the two groups (P > 0.05).
Relation of sdLDL-C levels and severity of CHD
Based on the CAG results of each individual, the diabetic patients with CHD were further divided into the following subgroups including multiple-vessel disease group, and high GS group for the purpose of intensively evaluating the relation of sdLDL-C to the severity of CHD (Table 2 and Table 3).
Table 2
baseline characteristics in type 2 diabetic patients with multiple-vessel disease of coronary heart disease patients
Variables | 1 vessel | 2 vessels | ≥ 3 vessels | P value |
N (%) | 576 (25.95%) | 656 (29.55%) | 988 (44.50%) | – |
Age (years) | 58.67 ± 10.72 | 59.79 ± 11.21 | 59.28 ± 9.88 | 0.700 |
Male (%) | 336 (58.3%) | 384 (58.5%) | 604 (61.1%) | 0.661 |
BMI (kg/m2) | 26.23 ± 2.9 | 26.57 ± 3.2 | 27.54 ± 3.5 | 0.156 |
Glucose (mmol/L) | 8.07 ± 2.32 | 7.61 ± 2.09 | 7.51 ± 2.11 | 0.095 |
HbA1c (%) | 7.77 ± 1.47 | 7.53 ± 1.39 | 7.59 ± 1.41 | 0.212 |
ApoB (mg/dL) | 67.65 ± 21.74 | 85.22 ± 20.72 | 101.77 ± 29.43 | < 0.001 |
ApoA1 (mg/dL) | 111.87 ± 31.49 | 115.85 ± 30.24 | 118.87 ± 26.41 | 0.071 |
Total cholesterol (mmol/L) | 4.35 (1.62) | 4.51 (1.70) | 4.68 (1.85) | 0.037 |
Triglycerides (mmol/L) | 1.32 (0.82) | 1.38 (0.83) | 1.30 (0.78) | 0.723 |
HDL-C (mmol/L) | 0.89 (0.32) | 0.85 (0.30) | 0.82 (0.27) | 0.537 |
LDL-C (mmol/L) | 2.68 (1.05) | 2.83 (1.00) | 2.99 (1.34) | 0.014 |
Lp(a) (nmol/L) | 37.80 (40.61) | 41.51 (49.94) | 39.47 (45.54) | 0.189 |
hs-CRP (mg/L) | 5.60 (8.03) | 4.41 (7.12) | 3.10 (6.57) | 0.002 |
HCY (umol/L) | 11.60 (8.14) | 12.69 (10.37) | 12.00 (11.53) | 0.078 |
sdLDL-C (mmol/L) | 0.72 (0.24) | 0.80 (0.24) | 0.85 ( 0.52) | 0.003 |
Data are reported as means ± SD or n(%), median (interquartile ranges). SD: Standard deviation |
BMI: body mass index; HbA1c: Hemoglobin A1c; apoB : apolipoprotein B ; apoA1 : apolipoprotein A1; HDL-C: high density lipoprotein cholesterol; LDL-C : low density lipoprotein cholesterol ; Lp(a): lipoprotein (a); HsCRP : hypersensitive C-reactive protein; HCY : homocysteine ; sdLDL-C : small dense low-density lipoprotein cholesterol. |
Statistical analysis was performed with the ANOVA or Kruskal – Wall test and and with Chi-square test for categorical variables. |
Table 3
baseline characteristics in type 2 diabetic patients with Gensini score of coronary heart disease patients
Variables | Low GS | Intermediate GS | High GS | P value |
N (%) | 724 (32.62%) | 768 (34.59%) | 728 (32.79%) | – |
Age (years) | 59.65 ± 10.02 | 60.11 ± 10.43 | 58.72 ± 8.91 | 0.776 |
Male (%) | 420 (58.01%) | 464 (60.42%) | 440 (60.44%) | 0.744 |
BMI (kg/m2) | 26.46 ± 3.28 | 26.26 ± 3.19 | 26.89 ± 3.47 | 0.540 |
Glucose (mmol/L) | 8.11 ± 2.31 | 7.72 ± 2.02 | 7.64 ± 2.10 | 0.181 |
HbA1c (%) | 7.81 ± 1.48 | 7.55 ± 1.42 | 7.57 ± 1.39 | 0.197 |
ApoB (mg/dL) | 82.17 ± 26.06 | 86.67 ± 22.58 | 90.78 ± 30.37 | 0.006 |
ApoA1 (mg/dL) | 115.25 ± 29.75 | 113.02 ± 31.57 | 117.03 ± 26.89 | 0.412 |
Total cholesterol (mmol/L) | 4.37 (1.40) | 4.49 (1.41) | 4.73 (1.83) | 0.012 |
Triglycerides (mmol/L) | 1.32 (0.76) | 1.25 (0.66) | 1.37 (0.83) | 0.332 |
HDL-C (mmol/L) | 0.88 (0.33) | 0.86 (0.30) | 0.84 (0.24) | 0.698 |
LDL-C (mmol/L) | 2.77 (1.04) | 2.89 (1.07) | 3.09 (1.45) | 0.026 |
Lp(a) (nmol/L) | 38.54 (40.71) | 40.09 (45.17) | 41.17 (51.39) | 0.664 |
hs-CRP (mg/L) | 3.40 (7.08) | 4.55 (11.32) | 4.06 (8.39) | 0.476 |
HCY (umol/L) | 11.35 (10.15) | 12.27 (9.29) | 12.69 (11.79) | 0.045 |
sdLDL-C (mmol/L) | 0.71 (0.29) | 0.80 (0.27) | 0.91 (0.53) | < 0.001 |
Data are reported as means ± SD or n(%), median (interquartile ranges). SD: Standard deviation |
BMI: body mass index; HbA1c: Hemoglobin A1c; apoB : apolipoprotein B ; apoA1 : apolipoprotein A1; HDL-C: high density lipoprotein cholesterol; LDL-C : low density lipoprotein cholesterol ; Lp(a) : lipoprotein (a); HsCRP : hypersensitive C-reactive protein; HCY : homocysteine ; sdLDL-C : small dense low-density lipoprotein cholesterol. |
Statistical analysis was performed with the ANOVA or Kruskal – Wall test and and with Chi-square test for categorical variables. |
The patients with diabetes and CHD were then classified into single-vessel (n = 576), two-vessel (n = 656), and multiple-vessel disease (n = 988) groups (Table 2). We found a significant increase in sdLDL-C levels in patients with multiple-vessel diseases group [0.72 (0.24) mmol/L vs. 0.80 (0.24) mmol/L vs. 0.85 (0.52) mmol/L, P = 0.003]. At the same time, these patients were divided into three groups according to the tertiles of GS: low GS (≤ 25, n = 724), intermediate GS (26–40, n = 768) and high GS (≥ 41, n = 728) group (Table 3). It can be seen from the results that the serum sdLDL-C levels in the high GS group was significantly higher than that in the other two groups [0.71 (0.29) mmol/L vs. 0.80 (0.27) mmol/L vs. 0.91 (0.53) mmol/L, P < 0.001].
After dividing diabetic patients with CHD into four groups according to quartiles of sdLDL-C levels, The results show that there is a linear correlation between the level of sdLDL-C and the multiple-vessel disease group and the high GS group. With the increase of serum sdLDL-C, the degree of CHD obstruction is more serious. (Table 4) (P < 0.001).
Table 4
Linear relationship between small dense low-density lipoprotein cholesterol levels and severity of coronary heart disease
sdLDL-C (mmol/L) | 1 vessel | 2 vessel | ≥ 3 vessels | P | | Low GS | Intermediate GS | High GS | P |
0.12–0.58 | 215 | 160 | 173 | < 0.001 | | 267 | 161 | 124 | < 0.001 |
0.58–0.80 | 147 | 203 | 212 | | 180 | 256 | 160 |
0.81–1.07 | 103 | 151 | 296 | | 129 | 189 | 210 |
1.07–2.31 | 111 | 142 | 307 | | 146 | 162 | 234 |
sdLDL-C: small dense low-density lipoprotein cholesterol; GS: Gensini Score. |
Statistical analysis was performed with the Mantel-Haenszel test for linear trend. |
Table 5
Odd ratios of CHD, multiple-vessel disease and high GS in relation to quartiles of small dense low-density lipoprotein
Variables | sdLDL-C, mmol/L |
< 0.58 | 0.58–0.74 | 0.75–0.95 | > 0.95 |
CHD | | | | |
Model 1 a | | | | |
Odds ratio (95% CI) | 1.00 (Ref.) | 2.168 (1.062–5.364) | 3.668 (1.260–8.166) | 3.015 (2.014–5.878) |
P value | – | 0.225 | 0.129 | 0.019 |
Model 2 b | | | | |
Odds ratio (95% CI) | 1.00 (Ref.) | 1.996 (1.226–5.926) | 2.087 (1.398–6.876) | 2.705 (1.617–5.645) |
P value | – | 0.398 | 0.198 | 0.042 |
Model 3 c | | | | |
Odds ratio (95% CI) | 1.00 (Ref.) | 1.926 (1.162–4.964) | 2.242 (1.401–6.564) | 2.757 (1.662–5.364) |
P value | – | 0.341 | 0.143 | 0.023 |
Multiple-vessel disease | | | | |
Model 1 a | | | | |
Odds ratio (95% CI) | 1.00 (Ref.) | 2.152 (1.298–4.312) | 3.911 (2.127–9.113) | 4.281 (2.468–6.561) |
P value | – | 0.156 | 0.078 | < 0.001 |
Model 2 b | | | | |
Odds ratio (95% CI) | 1.00 (Ref.) | 2.412 (1.353–4.003) | 3.677 (1.708–9.542) | 3.961 (1.786–6.986) |
P value | – | 0.107 | 0.129 | 0.014 |
Model 3 c | | | | |
Odds ratio (95% CI) | 1.00 (Ref.) | 2.302 (1.310–4.212) | 3.558 (1.801–7.145) | 3.788 (1.866–7.685) |
P value | – | 0.121 | 0.009 | 0.026 |
High GS | | | | |
Model 1 a | | | | |
Odds ratio (95% CI) | 1.00 (Ref.) | 1.907 (1.145–5.920) | 3.465 (2.050–5.637) | 3.391 (2.131–5.557) |
P value | – | 0.101 | 0.045 | < 0.001 |
Model 2 b | | | | |
Odds ratio (95% CI) | 1.00 (Ref.) | 2.172 (1.210–6.812) | 2.958 (1.602–8.331) | 3.122 (1.901–5.721) |
P value | – | 0.199 | 0.171 | 0.028 |
Model 3 c | | | | |
Odds ratio (95% CI) | 1.00 (Ref.) | 1.902 (1.010–5.412) | 2.902 (1.619–7.912) | 3.054 (1.944–5.699) |
P value | – | 0.191 | 0.121 | 0.022 |
sdLDL-C: small dense low-density lipoprotein cholesterol; GS: Gensini Score; CHD: coronary heart disease; CI: Confidence interval. |
a Univariate model. |
b Adjusted for age, sex, and body mass index. |
c Additionally adjusted for Hemoglobin A1c, apolipoprotein B, apolipoprotein A1, high density lipoprotein cholesterol, low density lipoprotein cholesterol, lipoprotein (a), hypersensitive C-reactive protein, and homocysteine. |
For exploring the role of sdLDL-C in CHD, univariate and multivariate regression analyses were also performed in our study. All participants were divided into four quartiles of sdLDL-C levels, and the present and severity of CHD in individuals with different sdLDL-C levels was assessed. Through univariate logistic regression, sdLDL-C levels were associated with the presence and severity of CHD (CHD group vs. non–CHD group: OR = 3.015, 95% CI: 2.014–5.878, P = 0.019; multiple-vessel disease group vs. single-vessel disease group: OR = 4.281, 95% CI: 2.468–6.561, P < 0.001; high GS group vs. low GS group: OR = 3.391, 95% CI: 2.131–5.557, P < 0.001). The multiple-factor logistic regression was applied to adjust for age, gender, BMI, glucose, HbA1c, ApoB, ApoA1, TC, TG, HDL-C, LDL-C, Lp(a), hs-CRP, and HCY, sdLDL-C levels remained to be independently associated with the presence and severity of CHD (CHD group vs. non–CHD group: OR = 2.757, 95% CI: 1.662–5.364, P = 0.023; multiple-vessel disease group vs. single-vessel disease group: OR = 3.788, 95% CI: 1.866–7.685, P = 0.026; high GS group vs. low GS group: OR = 3.054, 95% CI: 1.944–5.699, P = 0.022).