Baseline characteristics of the population involved in this study
Clinical and biochemical characteristics of the participants were listed in Table 1, NAFLD patients tended to be men and possessed higher body mass index (BMI), systolic blood pressure (SBP), diastolic blood pressure (DBP), fasting blood glucose (FBG), HbA1c, TC, TG, LDL-C, TC/HDL-C, TG/HDL-C, non-HDL-C, serum uric acid, ALT, AST, GGT while lower HDL-C (all P < 0.05) when compared to non-NAFLD individuals. Notably, no difference existed in terms of age between the two groups.
Table 1
Baseline characteristics of individuals with or without NAFLD
| Non-NAFLD (n = 1366) | NAFLD (n = 2036) |
Age(years) | 49.02 ± 10.81 | 49.42 ± 10.08 |
Sex(male/Female) | 689/677 | 1577/459* |
BMI (kg/m2) | 22.48 ± 3.77 | 26.61 ± 4.55* |
SBP (mmHg) | 122.85 ± 17.69 | 130.74 ± 16.43 * |
DBP (mmHg) | 74.67 ± 11.15 | 81.17 ± 10.95 * |
FBG (mmol/L) | 5.26 ± 1.06 | 5.77 ± 1.39* |
HbA1c (%) | 5.53 ± 0.62 | 5.80 ± 0.87* |
TC (mmol/L) | 5.28 ± 1.04 | 5.41 ± 1.06 * |
TG (mmol/L) | 1.30 ± 0.59 | 2.02 ± 1.10* |
LDL-C(mmol/L) | 3.23 ± 0.77 | 3.44 ± 0.76* |
HDL-C(mmol/L) | 1.44 ± 0.32 | 1.22 ± 0.25* |
TG/HDL-C | 0.98 ± 0.56 | 1.77 ± 1.17* |
TC/HDL-C | 3.78 ± 0.89 | 4.54 ± 0.97* |
non-HDL-C | 3.84 ± 0.97 | 4.19 ± 0.98* |
Uric acid (mmol/l) | 310.80 ± 80.71 | 370.73 ± 84.23* |
ALT (U/L) | 19.85 ± 10.71 | 29.97 ± 17.09* |
AST (U/L) | 22.46 ± 7.48 | 24.87 ± 8.44* |
GGT (U/L) | 25.98 ± 19.87 | 41.96 ± 28.07* |
Values are presented as mean ± standard deviation. |
BMI, body mass index; SBP, systolic blood pressure; DBP, diastolic blood pressure; FBG, fasting blood glucose ; TC, total cholesterol; TG, triacylglyceride; LDL-C, high-density lipoprotein cholesterol; HDL-C, high-density lipoprotein cholesterol; ALT: alanine aminotransferase; AST aspartate transaminase; GGT: gamma-glutamyl transpeptidase. Compared with non-NAFLD, *P < 0.05 |
Lipid Ratios Are Associated With Hepatic Steatosis
In accordance with the FAP value, NAFLD patients were further divided into three groups: the mild (n = 735), the moderate (n = 559) and the severe NAFLD group (n = 742). Interestingly, there were pronouncedly differences in TG, TC/HDL-C, TG/HDL-C and HDL-C among the mild, moderate, and severe NAFLD groups (P < 0.05) (Fig. 1). Furthermore, patients in the moderate/severe group exhibited higher non-HDL-C than that in the mild NAFLD group (P < 0.05) (Fig. 1), whereas patients of the severe group displayed elevated TC relative to those in the mild/moderate NAFLD group (P < 0.05) (Fig. 1).
Baseline characteristics of individuals with or without liver fibrosis in NAFLD
In line with the LSM value, NAFLD patients were further differentiated into the non-liver (n = 1665) and liver fibrosis groups (n = 371). As listed in Table 2, patients with liver fibrosis similarly tended to be men and displayed higher parameters in BMI, SBP, DBP, FBG, HbA1c, TG, TC/HDL-C, TG/HDL-C, non-HDL-C, serum uric acid, ALT, AST, GGT while lower HDL-C (all P < 0.05) relative to individuals without liver fibrosis. Likewise, these two groups exhibited no differences of age, TC and LDL-C.
Table 2
Baseline characteristics of individuals with or without liver fibrosis in NAFLD
| Non-liver fibrosis (n = 1665) | liver fibrosis(n = 371) |
Age(years) | 49.29 ± 9.88 | 50.02 ± 10.91 |
Sex(male/Female) | 1272/293 | 305/66* |
BMI (kg/m2) | 26.14 ± 4.43 | 28.70 ± 4.47* |
SBP (mmHg) | 129.66 ± 16.16 | 135.43 ± 16.80 * |
DBP (mmHg) | 80.68 ± 10.95 | 83.34 ± 10.73 * |
FBG (mmol/L) | 5.67 ± 1.30 | 6.18 ± 1.68* |
HbA1c (%) | 5.74 ± 0.81 | 6.06 ± 1.09* |
TC (mmol/L) | 5.40 ± 1.06 | 5.48 ± 1.07 |
TG (mmol/L) | 1.93 ± 0.90 | 2.44 ± 1.68* |
LDL-C(mmol/L) | 3.43 ± 0.77 | 3.47 ± 0.75 |
HDL-C(mmol/L) | 1.23 ± 0.24 | 1.17 ± 0.25* |
TG/HDL-C | 1.66 ± 0.91 | 2.23 ± 1.88* |
TC/HDL-C | 4.47 ± 0.94 | 4.83 ± 1.09* |
non-HDL-C | 4.16 ± 0.98 | 4.32 ± 0.99* |
Uric acid (mmol/l) | 367.33 ± 83.91 | 385.98 ± 84.02* |
ALT (U/L) | 28.42 ± 15.92 | 36.97 ± 20.17* |
AST (U/L) | 24.12 ± 7.81 | 28.22 ± 10.19* |
GGT (U/L) | 40.56 ± 27.31 | 48.28 ± 30.48* |
Values are presented as mean ± standard deviation. |
BMI, body mass index; SBP, systolic blood pressure; DBP, diastolic blood pressure; FBG, fasting blood glucose ; TC, total cholesterol; TG, triacylglyceride; LDL-C, high-density lipoprotein cholesterol; HDL-C, high-density lipoprotein cholesterol; ALT: alanine aminotransferase; AST aspartate transaminase; GGT: gamma-glutamyl transpeptidase. Compared with non-liver fibrosis, *P < 0.05 |
Multinomial logistic regression assessment the risk of hepatic steatosis severity
After adjusting for sex, BMI, SBP, DBP, FBG, HbA1c, uric acid, ALT, AST and GGT, TG, HDL-C, TG/HDL-C, TC/HDL-C and non-HDL-C were all significantly correlated with the severity of hepatic steatosis. Briefly, compared to those without NAFLD, the odds ratios of TG for the mild, moderate and severe NAFLD were 1.904 (95% CI 1.610–2.251, P < 0.001), 2.173 (95% CI 1.817-2.600, P < 0.001), 2.512 (95% CI 2.090–3.019, P < 0.001), respectively. The odds ratios of HDL-C for the mild, moderate and severe NAFLD were 0.355 (95% CI 0.232–0.543, P < 0.001), 0.260 (95%CI 0.156–0.432, P < 0.001), 0.178 (95%CI 0.101–0.313, P < 0.001), respectively. The odds ratios of TG/HDL-C for mild, moderate and severe NAFLD were 1.967 (95%CI 1.659–2.333, P < 0.001), 2.314 (95%CI 1.930–2.773, P < 0.001), 2.570 (95%CI 2.134–3.095, P < 0.001), respectively. The odds ratios of TC/HDL-C for mild, moderate and severe NAFLD were 1.301 (95%CI 1.149–1.472, P < 0.001), 1.609 (95%CI 1.398–1.851, P < 0.001) and 1.775 (95%CI 1.526–2.065, P < 0.001), respectively. The odds ratios of non-HDL-C for mild, moderate and severe NAFLD were 1.093 (95%CI 0.978–1.222, P = 0.116), 1.277 (95%CI 1.125–1.450, P < 0.001), 1.341 (95%CI 1.169–1.538, P < 0.001), respectively.
Binary logistic regression analysis for the risk of liver fibrosis in NAFLD
In line with binary logistic regression analysis, TG (OR = 1.341, 95%CI 1.195–1.505, P < 0.001), HDL-C (OR = 0.512, 95%CI 0.292–0.895, P = 0.019), TG/HDL-C (OR = 1.322, 95%CI 1.178–1.483, P < 0.001) and TC/HDL-C (OR = 1.252, 95%CI 1.098–1.427, P = 0.001) presented a positive correlation with liver fibrosis upon adjusting for sex, BMI, SBP, DBP, FBG, HbA1c, uric acid, ALT, AST and GGT. On the contrary, there were no obvious relationship of NAFLD with TC, LDL-C, or non-HDL-C following the adjustment for sex, BMI, SBP, DBP, FBG, HbA1c, uric acid, ALT, AST and GGT.
Diagnostic Value Of Lipid Parameters For Nafld
The cut-off points of lipid parameters for predicting NAFLD, together with their corresponding specificity and sensitivity, were summarized in Table 3 and Fig. 2. Higher AUROC value of TG/HDL-C than those of TC, TG, LDL-C, HDL-C, TC/HDL-C and non-HDL-C was observed. Accordingly, the AUROC and optimal cut-off point of TG/HDL-C was 0.771 (95%CI 0.755–0.787) and 1.08 (sensitivity: 72.2%, specificity: 68.3%), respectively, suggesting that TG/HDL-C had better predictive effects than other lipid parameters and was an acceptable predictor of NAFLD.
Table 3
ROC curve for predicting NAFLD and cut-off points for maximum sum of sensitivity and specificity
| ROC (95%CI) | P | Cut-off point | Sensitivity (%) | Specificity (%) |
TC (mmol/L) | 0.538(0.518–0.558) | 0.010 | 5.29 | 0.521 | 0.542 |
TG (mmol/L) | 0.748(0.731–0.764) | 0.008 | 1.40 | 0.698 | 0.675 |
LDL-C(mmol/L) | 0.583(0.564–0.603) | 0.010 | 3.35 | 0.538 | 0.602 |
HDL-C(mmol/L) | 0.292(0.274–0.310) | 0.009 | 1.30 | 0.641 | 0.676 |
TG/HDL-C | 0.771(0.755–0.787) | 0.008 | 1.08 | 0.722 | 0.683 |
TC/HDL-C | 0.721(0.703–0.738) | 0.009 | 4.03 | 0.681 | 0.649 |
non-HDL-C | 0.605(0.586–0.625) | 0.010 | 3.94 | 0.581 | 0.583 |
Diagnostic value of lipid parameters for liver fibrosis in NAFLD
The cut-off points of lipid parameters for predicting liver fibrosis, together with their corresponding specificity and sensitivity, were listed in Table 4 and Fig. 3. AUROC value of TG/HDL-C was larger than that of TG, HDL-C and TC/HDL-C. However, The AUROC value of TG/HDL-C(0.60 < AUROC < 0.70) for liver fibrosis was relatively smaller than that for NAFLD, which indicated that TG/HDL-C could not be acceptable predictors of liver fibrosis in NAFLD.
Table 4
ROC curve for predicting liver fibrosis and cut-off points for maximum sum of sensitivity and specificity
| ROC (95%CI) | P | Cut-off point | Sensitivity (%) | Specificity (%) |
TG (mmol/L) | 0.599(0.567–0.630) | 0.016 | 1.97 | 0.515 | 0.607 |
HDL-C(mmol/L) | 0.415(0.383–0.447) | 0.016 | 1.19 | 0.534 | 0.572 |
TG/HDL-C | 0.610(0.579–0.641) | 0.016 | 1.70 | 0.518 | 0.621 |
TC/HDL-C | 0.597(0.565–0.630) | 0.017 | 4.52 | 0.601 | 0.553 |