Patient characteristics
The 4,445 patients who had undergone elective PCI at the Sir Run Run Shaw Hospital between January 2009 and April 2019 comprised 3,538 males and 907 females. Overall, the median age of subjects was 64 (58-70) years old, with a median BMI of 24.73 (22.77-26.18) kg·m-2, 64% had hypertension and 25.5% had type 2 diabetes mellitus. The median value of HbA1c was 5.9%, with the interquartile range from 5.5% to 6.7% for all subjects. The variability of LDL-C, non-HDL-C, TC and TG was each significantly higher in patients with HbA1c≥6.5% than in those with HbA1c<6.5%. Patients with HbA1c≥6.5% appeared to have higher BMI (24.73[23.38-26.67] vs. 24.62[22.48-26.00]); p<0.001), more likely to have hypertension (70.0% vs. 62.5%; p < 0.001) than those with HbA1c<6.5%. Table 1 summarizes the baseline characteristics of the enrolled patients categorized by HbA1c levels.
Table 1 Baseline characteristics of patients
Characteristics
|
Total (n=4445)
|
HbA1c<6.5% (n=3538)
|
HbA1c≥6.5% (n=907)
|
P-value
|
Demographic information
|
Age (Years)
|
64.00(58.00-70.00)
|
64.00(58.00-70.00)
|
64.00(58.00-71.00)
|
0.158
|
Male, N (%)
|
3187(71.7)
|
2549(72.0)
|
638(70.3)
|
0.391
|
BMI, (kg/m2)
|
24.73(22.77-26.18)
|
24.62(22.48-26.00)
|
24.73(23.38-26.67)
|
<0.001
|
Current smoking, N (%)
|
1102(24.8)
|
890(25.2)
|
212(23.4)
|
0.388
|
Hypertension, N (%)
|
2845(64.0)
|
2210(62.5)
|
635(70.0)
|
<0.001
|
Type 2 diabetes, N (%)
|
1133(25.5)
|
327(9.2)
|
806(88.9)
|
<0.001
|
Previous MI, N (%)
|
164(3.7)
|
129(3.6)
|
35(3.9)
|
0.786
|
Previous PCI, N (%)
|
342(7.7)
|
278(7.9)
|
64(7.1)
|
0.581
|
LDL-C<1.8 mmol/L, N (%)
|
3729(83.9)
|
2984(84.3)
|
745(82.1)
|
0.127
|
Laboratory examination
|
HbA1c (%)
|
5.9(5.50-6.70)
|
5.7(5.40-6.00)
|
7.6(6.90-8.70)
|
<0.001
|
LDL-C (mean, mmol/L)
|
1.78(1.49-2.13)
|
1.78(1.50-2.12)
|
1.77(1.47-2.18)
|
0.834
|
HDL-C (mean, mmol/L)
|
1.02(0.88-1.20)
|
1.05(0.90-1.22)
|
0.97(0.83-1.14)
|
<0.001
|
non-HDL-C (mean, mmol/L)
|
2.46(2.10-2.90)
|
2.47(2.10-2.87)
|
2.44(2.08-2.95)
|
0.806
|
TC (mean, mmol/L)
|
3.66(3.21-4.16)
|
3.67(3.25-4.12)
|
3.62(3.15-4.23)
|
0.219
|
TG (mean, mmol/L)
|
1.36(1.04-1.82)
|
1.35(1.04-1.78)
|
1.38(1.05-1.95)
|
0.051
|
LDL-C (SD)
|
0.47(0.27-0.75)
|
0.45(0.25-0.74)
|
0.50(0.29-0.76)
|
0.014
|
HDL-C (SD)
|
0.13(0.08-0.18)
|
0.13(0.08-0.18)
|
0.13(0.08-0.18)
|
0.577
|
non-HDL-C (SD)
|
0.43(0.25-0.70)
|
0.42(0.25-0.70)
|
0.47(0.27-0.73)
|
0.004
|
TC (SD)
|
0.59(0.35-0.93)
|
0.56(0.33-0.90)
|
0.66(0.39-1.00)
|
<0.001
|
TG (SD)
|
0.33(0.19-0.55)
|
0.32(0.19-0.52)
|
0.37(0.20-0.65)
|
<0.001
|
|
89.25(75.22-98.11)
|
89.22(75.96-97.70)
|
89.19(70.65-99.01)
|
0.848
|
Baseline medication
|
ACEI, N (%)
|
1102(24.8)
|
876(24.8)
|
226(24.9)
|
0.897
|
ARB, N (%)
|
1565(35.2)
|
1180(33.4)
|
385(42.4)
|
<0.001
|
Beta blocker, N (%)
|
2614(58.8)
|
2092(59.1)
|
522(57.6)
|
0.429
|
CCB, N (%)
|
1325(29.8)
|
1020(28.8)
|
305(33.6)
|
0.007
|
Aspirin, N (%)
|
4294(96.6)
|
3424(96.8)
|
870(95.9)
|
0.244
|
Clopidogrel, N (%)
|
3592(80.8)
|
2889(81.7)
|
703(77.5)
|
0.007
|
Ticagrelor, N (%)
|
805(18.1)
|
613(17.3)
|
192(21.2)
|
0.008
|
Statin, N (%)
|
4401(99.0)
|
3507(99.1)
|
894(98.6)
|
0.151
|
Intensive statin, N (%)
|
845(19.0)
|
660(18.7)
|
185(20.3)
|
0.064
|
Statin combined with ezetimibe, N (%)
|
956(21.5)
|
764(21.6)
|
192(21.2)
|
0.818
|
Data are expressed as median (25%-75%) or n (%). Total indicates total group; SD, standard deviation; BMI, body mass index; MI, myocardial infarction; LDL-C < 1.8 mmol/L , LDL-C < 1.8 mmol/L at the first-month follow-up after percutaneous coronary intervention (PCI); LDL-C, low-density lipoprotein cholesterol; HDL-C, high-density lipoprotein cholesterol; TC, total cholesterol; TG, triglyceride; eGFR, estimated glomerular filtration rate; ACEI, angiotensin-converting enzyme inhibitors; ARB, angiotensin receptor blocker; CCB, calcium channel blocker
Results of univariate and multivariate linear regression for the variability of lipid profiles
Based on clinical considerations and differences in baseline characteristics according to HbA1c categories, the following factors were included in the univariate analysis: HbA1c, age, gender, BMI, current smoking, hypertension, eGFR, types of statin, intensive statin treatment, statin combined with ezetimibe and the corresponding mean values of lipids. Factors that were significant in the univariate analyses (p<0.05) were included in multivariate linear regression analysis.
Multivariate analysis for the effect of HbA1c on lipid variability was conducted in all patients and demonstrated that HbA1c was a potential risk factor for the variability of lipids, which included LDL-C (regression coefficients of HbA1c on SD [β] 0.014, standard error [SE] 0.004, P-value<0.001), non-HDL-C ([β] 0.023, [SE] 0.004, P-value<0.001), TC ([β] 0.041, [SE] 0.005, P-value<0.001), and TG ([β] 0.033, [SE] 0.005, P-value<0.001). Besides, HbA1c remained a potential risk factor for the variability of LDL-C, non-HDL-C, TC and TG when CV and VIM were employed to represent lipid variability, respectively (see Table 2 to 5).




Results of the multivariate linear regression in subgroups
In multivariate subgroup analyses, the relationship between HbA1c and the variability of LDL-C, non-HDL-C, TC, and TG did not significantly vary across several subgroups such as non-diabetes, diabetes, atorvastatin, rosuvastatin, regular statin, intensive statin and statin-ezetimibe combined therapy.
Figures 1-3 present the results of subgroup analyses when lipid variability was represented by SD. Similarly, when CV and VIM were employed to represent lipid variability, respectively, subgroup analysis results were consistent with results when using SD. (see Table 6).
