Characteristics of participants
Participants were screening by inclusion and exclusion criteria. Finally, a total of 164 participants with HD and 71 healthy controls were included in the analyses (Fig. 1). The mean ages of participants with HD and healthy controls were 63 and 49.9 years, respectively. The male-to-female percentages in the HD cohort and healthy controls were 48.8–51.2% and 31.0–69.0%, respectively. In the comparison of main laboratory parameters, HD patients showed a significantly lower HDL-2b subclass proportion compared with healthy controls (23.6% vs. 31.2%, P < 0.001) as well as lower total cholesterol (152 vs. 189 mg/dL, P < 0.001), HDL-C (44.5 vs. 59.8 mg/dL, P < 0.001), and LDL-C (88.1 vs. 112.1 mg/dL, P < 0.001) levels. The HDL-3 subclass proportion was not significantly different between the HD patients and healthy controls (31.7% vs. 33.6%, P = 0.137) (Table 1).
Table 1
Baseline characteristics (N = 235).
Variables | HD (n = 164) | Control (n = 71) | P |
Age (years) | 63.1 ± 12.3 | 49.9 ± 10.6 | < 0.001 |
Sex | | | 0.017 |
female | 84 (51.2%) | 49 (69.0%) | |
male | 80 (48.8%) | 22 (31.0%) | |
BMI(kg/m2) | 23.5 ± 12.5 | 23.3 ± 4.1 | 0.925 |
Dialysis vintage (years) | 10.48 ± 7.53 | - | - |
Diabetes | 27 (16.5%) | N/A | - |
CVA | 3 (1.8%) | N/A | - |
CAD | 6 (3.7%) | N/A | - |
Antihypertensive | 66 (40.2%) | - | |
Lipid-lowering drugs | 24 (14.6%) | - | |
Etiology of kidney failure | | | - |
Primary kidney disease | 61 (37.2%) | N/A | |
Systemic disease | 79 (48.2%) | N/A | |
Unknown | 24 (14.6%) | N/A | |
Laboratory measurements | | | |
Total Cholesterol (mg/dL) | 152 (94–314) | 189 (135–310) | < 0.001 |
Triglyceride (mg/dL) | 108 (30–994) | 80.5 (18–237) | < 0.001 |
HDL-C (mg/dL) | 44.5 ± 15.4 | 59.8 ± 14.0 | < 0.001 |
HDL-2b (%) | 23.6 ± 9.1 | 31.2 ± 6.7 | < 0.001 |
HDL-3 (%) | 31.7 ± 11 | 33.6 ± 7.5 | 0.137 |
LDL-C (mg/dL) | 88.1 ± 35.0 | 112.1 ± 30.8 | < 0.001 |
Intact-PTH (pg/ml) | 268.2 (2.4–2819.9) | 53.6 (20.9–90.2) | < 0.001 |
Albumin (g/dL) | 3.9 ± 0.3 | 4.2 ± 0.8 | 0.075 |
hs-CRP (mg/L) | 6.9 ± 13.0 | 2.7 ± 5.0 | 0.016 |
Hemoglobin (g/dL) | 10.7 ± 1.2 | 12.6 ± 1.7 | < 0.001 |
Total leukocytes (109/L) | 6.3 ± 2.4 | 6.1 ± 1.7 | 0.567 |
BUN (mg/dL) | 69 (32–151) | 13 (7–46) | < 0.001 |
Cr (mg/dL) | 10.4 ± 2.3 | 0.7 ± 0.2 | < 0.001 |
Abbreviations: BMI, body mass index; CVA, cerebral vascular accident; CAD, coronary artery disease; HDL, high-density lipoprotein; LDL, low-density lipoprotein; VLDL, very low-density lipoprotein; C, cholesterol; T, total; PTH, parathyroid hormone; BUN, blood urea nitrogen; Cr, creatinine; hs-CRP, high-sensitivity C-reactive protein. |
Pearson correlation analysis on study parameters
The results from the Pearson correlation test showed that the HDL-2b subclass proportion was significantly negatively correlated with age (r = -0.26, P < 0.001), HDL-3 subclass proportion (r = -0.54, P < 0.001), triglyceride (r = -0.44, P < 0.001), and total leukocyte count (r = -0.16, P < 0.05). On the other hand, it was significantly positively correlated with HDL-C (r = 0.68, P < 0.001), total cholesterol (r = 0.21, P < 0.01), and hemoglobin (r = 0.16, P < 0.05). Similarly, the HDL-3 subclass proportion was significantly negatively correlated with the HDL-2b subclass proportion (r = -0.54, P < 0.001) and HDL-C (r = -0.52, P < 0.001) and positively correlated with triglyceride (r = 0.51, P < 0.001), hemoglobin (r = 0.14, P < 0.05), and total leukocyte count (r = 0.19, P < 0.01) (Table 2).
Table 2
Pearson correlation analysis.
Variables | HDL-2b (%) | HDL-3(%) |
Age (years) | -0.26** | 0.01 |
Total Cholesterol (mg/dL) | 0.21** | -0.03 |
Triglyceride (mg/dL) | -0.44*** | 0.51*** |
HDL-C (mg/dL) | 0.68*** | -0.52*** |
HDL-2b (%) | 1.00 | -0.54*** |
HDL-3 (%) | -0.54*** | 1.00 |
LDL-C (mg/dL) | 0.10 | 0.02 |
Intact-PTH (pg/ml) | < 0.001 | -0.03 |
Albumin (g/dL) | 0.05 | 0.13 |
hs-CRP (mg/L) | -0.11 | < 0.001 |
Hemoglobin (g/dL) | 0.16* | 0.14* |
Total leukocytes (109/L) | -0.16* | 0.19** |
*p < 0.05, **p < 0.01, ***p < 0.001. |
- Figure 1. Participants flow diagram. |
Influence of sex on the HDL-2b and HDL-3 subclass proportions
Both sexes in the HD cohort demonstrated significantly lower HDL-2b and HDL-3 subclass proportions compared with healthy controls. On the other hand, the HDL-2b and HDL-3 subclass proportions were not different between sexes in the HD cohort (Fig. 2).
Associations of the hs-CRP levels with the HDL-2b and HDL-3 subclass proportions
We stratified the entire cohort with the cutoff hs-CRP level of 3 mg/L (normal range < 3 mg/L in the laboratory) and examined the associations with the HDL-2b and HDL-3 subclass proportions. The results showed that the HDL-2b (P = 0.031) and HDL-3 (P = 0.030) subclass proportions were significantly lower in the HD cohort under the hs-CRP level of < 3 mg/L compared with healthy controls. Similarly, the HDL-3 (P = 0.004) subclass proportion was significantly lower in the HD cohort under the hs-CRP level of ≥ 3 mg/L compared with healthy controls. However, this relationship was not noted in the HDL-2b(P = 0.274) subclass proportion (Fig. 3 − 1). We further examined the associations of the hs-CRP levels < 3 mg/L with the HDL-2b and HDL-3 subclass proportions in the HD cohort. The results showed that the HDL-2b (P = 0.005) subclass proportion was significantly lower under hs-CRP levels ≥ 3 mg/L compared with those with hs-CRP levels < 3 mg/L. In contrast, HDL-3 (P = 0.022) subclasses revealed an opposite trend (Fig. 3 − 2).
Influence of diabetes on the HDL-2b and HDL-3 subclass proportions in the HD cohort
Diabetic patients with HD did not demonstrate significant differences in the HDL-2b and HDL-3 subclass proportions compared with nondiabetic HD patients (Fig. 4).