Table 1.
Baseline characteristics of the hepcidin quartile group.
| Serum hepcidin quartile group (n = 2090) | P-trend | ||||
|---|---|---|---|---|---|
| 1Q (n = 515) | 2Q (n = 529) | 3Q (n = 521) | 4Q (n = 525) | ||
| Age (years) | 51.2 ± 12.6 | 53.8 ± 12.5* | 53.8 ± 11.7* | 55.4 ± 11.7* | <0.001 |
| Male sex | 49.3 | 62.0* | 66.6* | 66.1* | <0.001 |
| High income | 21.8 | 25.8 | 23.5 | 21.1 | 0.580 |
| Ever smoking | 38.8 | 45.5* | 50.3*† | 51.6* | <0.001 |
| Hypertension | 96.3 | 97.2 | 97.9† | 99.0* | 0.003 |
| SBP (mm Hg) | 125.6 ± 15.4 | 127.7 ± 15.2 | 128.5 ± 16.6* | 129.3 ± 17.4* | <0.001 |
| DBP (mm Hg) | 76.7 ± 11.1 | 77.2 ± 10.3 | 77.3 ± 11.5 | 76.8 ± 11.7 | 0.880 |
| Diabetes | 28.2 | 36.9* | 36.5*† | 43.8*‡ | <0.001 |
| Cause of CKD | |||||
| DMN | 17.5 | 23.6* | 26.5*† | 33.5*‡ | <0.001 |
| GN | 39.0 | 32.3* | 29.4*† | 24.2* | <0.001 |
| HN | 18.4 | 22.3 | 19.4 | 20.2 | 0.777 |
| Others | 25.0 | 21.7 | 24.8 | 22.1 | 0.485 |
| BMI (kg/m2) | 24.1 ± 3.5 | 24.6 ± 3.3 | 25.0 ± 3.5* | 24.4 ± 3.3 | 0.047 |
| Glucose (mmol/l) | 5.9 ± 1.9 | 6.2 ± 2.1 | 6.3 ± 2.6* | 6.2 ± 2.1 | 0.018 |
| BUN (mmol/l) | 8.3 ± 4.8 | 8.6 ± 4.1 | 10.1 ± 5.1*† | 13.3 ± 6.6*†‡ | <0.001 |
| Creatinine (μmol/l) | 128.6 ± 77.6 | 137.0 ± 72.9 | 162.4 ± 103.3*† | 216.9 ± 123.3*†‡ | <0.001 |
| eGFR (ml/min/1.73 m2) | 60.8 ± 32.5 | 55.7 ± 29.6* | 48.8 ± 28.5*† | 36.1 ± 23.9*†‡ | <0.001 |
| Bilirubin (μmol/l) | 11.5 ± 4.7 | 12.2 ± 5.6 | 11.6 ± 5.3 | 10.4 ± 5.0*†‡ | <0.001 |
| Albumin (g/l) | 41.7 ± 3.8 | 42.2 ± 4.0 | 41.8 ± 4.3 | 41.2 ± 4.9† | 0.013 |
| Cholesterol (mmol/l) | 4.6 ± 0.9 | 4.6 ± 1.0 | 4.6 ± 1.1 | 4.4 ± 1.0*†‡ | 0.002 |
| WBC (×103/μL) | 6.4 ± 1.9 | 6.5 ± 1.8 | 6.7 ± 1.9 | 6.8 ± 2.1* | 0.001 |
| Hemoglobin (g/dl) | 13.0 ± 1.9 | 13.3 ± 1.8 | 13.0 ± 2.1 | 11.9 ± 2.0*†‡ | <0.001 |
| Anaemia | 35.9 | 33.3 | 42.4*† | 65.5*‡ | <0.001 |
| ESA use | 2.9 | 3.8 | 5.4*† | 18.4*‡ | <0.001 |
| Iron supplements | 7.4 | 8.5 | 13.7*† | 29.3*‡ | <0.001 |
| TSAT (%) | 28.1 ± 12.4 | 31.4 ± 11.1* | 33.4 ± 11.7*† | 33.6 ± 12.4*† | <0.001 |
| Ferritin (pmol/l) | 95.4 (49.3–163.8) | 180.7 (120.6–285.9)* | 259.1 (170.5–394.3)*† | 446.7 (282.0–675.2)*†‡ | <0.001 |
| Hepcidin (ng/ml) | 3.9 (2.7–5.3) | 9.4 (7.9–11.3)* | 18.1 (15.5–21.1)*† | 38.1 (29.9–56.8)*†‡ | <0.001 |
| CRP (nmol/l) | 4.8 (1.9–12.4) | 5.4 (1.9–14.3) | 6.7 (2.9–17.1)*† | 7.6 (2.9–21.9)*†‡ | <0.001 |
| UPCR (g/g) | 0.4 (0.1–1.2) | 0.4 (0.1–1.2) | 0.5 (0.2–1.8)*† | 0.7 (0.2–2.1)*†‡ | <0.001 |
Q, quartile; SBP, systolic blood pressure; DBP, diastolic blood pressure; CKD, chronic kidney disease; DMN, diabetic nephropathy; GN, glomerulonephritis; HN, hypertensive nephropathy; BMI, body mass index; BUN, blood urea nitrogen; eGFR, estimated glomerular filtration rate; WBC, white blood cells; ESA, erythropoiesis stimulating agents; TSAT, transferrin saturation; CRP, C-reactive protein; UPCR, urine protein-to-creatinine ratio.
Values are expressed as mean ± standard deviation for normally distributed continuous variables, median (interquartile range) for non-normally distributed continuous variables, and percentage for categorical variables. P-trend was analyzed by linear-term of one-way ANOVA for normally distributed continuous variables, Jonckheere-Terpstra test for non-normally distributed continuous variables, and a linear-by-linear association for categorical variables. *,†, and ‡ meant P < 0.05 when compared to 1Q, 2Q, and 3Q of serum hepcidin, respectively, by using Bonferroni post-hoc analysis of one-way ANOVA for normally distributed continuous variables, Mann-Whitney U test for non-normally distributed continuous variables w, and chi-square test for categorical variables.