Table 1. Differences of baseline characteristics in Chinese non-dialysis CKD patients.
| Total (N = 588) | Dippers (N = 204) | Non-dippers (N = 256) | Reverse dippers (N = 106) | Extreme dippers (N = 22) | P-value | |
|---|---|---|---|---|---|---|
| Age (years) | 42.76 ± 16.71 | 40.19 ± 15.93 | 42.45 ± 17.10 | 48.55 ± 16.71* | 42.36 ± 13.07 | <0.001 |
| Male: female ratio | 336/252 | 122/82 | 151/105 | 51/55 | 12/10 | 0.209 |
| Course (months) | 6(1~24) | 4(1~24) | 6.0(1~24) | 4.5(1~14.25) | 10(1.75~36) | 0.419 |
| Diabetes mellitus (N/%) | 92(15.6%) | 22(10.8%) | 37(14.4%) | 27(25.5%)* | 6(27.3%) | 0.003 |
| Current smoker (N/%) | 109(18.5%) | 37(18.2%) | 46(18.0%) | 21(19.8%) | 5(22.7%) | 0.941 |
| Alcohol intake (N/%) | 55(9.3%) | 19(9.4%) | 22(8.6%) | 10(9.4%) | 4(18.2%) | 0.542 |
| BMI (kg/m2) | 23.16 ± 3.61 | 23.14 ± 3.59 | 23.10 ± 3.54 | 23.14 ± 3.73 | 24.22 ± 4.19 | 0.616 |
| History of cardiovascular disease (N/%) | 42(7.1%) | 10(4.9%) | 20(7.8%) | 10(9.4%) | 2(9.1%) | 0.443 |
| eGFR (mL/min per 1.73 m2) | 67.84(29.83~106.69) | 74.04(39.00~110.98) | 66.65(23.99~104.93) | 51.37(21.65~100.84)* | 57.31(92.72~117.32) | 0.004 |
| Hemoglobin (g/L) | 122.20 ± 24.15 | 127.11 ± 23.26 | 121.69 ± 24.23* | 112.71 ± 23.89* | 127.86 ± 19.36 | <0.001 |
| Albumin (g/L) | 33.30 ± 9.02 | 34.41 ± 9.14 | 32.65 ± 9.14 | 31.92 ± 8.30 | 37.23 ± 8.16 | 0.011 |
| Total calcium level (mmol/L) | 2.19 ± 0.20 | 2.21 ± 0.20 | 2.19 ± 0.21 | 2.15 ± 0.17* | 2.29 ± 0.17 | 0.006 |
| Phosphate level (mmol/L) | 1.26 ± 0.24 | 1.25 ± 0.21 | 1.28 ± 0.26 | 1.25 ± 0.24 | 1.15 ± 0.21 | 0.101 |
| iPTH (pg/mL) | 51.87 (31.56~87.89) | 44.18(28.64~72.82) | 57.80(36.42~108.68)* | 54.22(34.65~86.92) | 32(24.52~54.69) | 0.011 |
| Serum fasting glucose (mmol/L) | 5.09 ± 1.44 | 5.05 ± 1.23 | 5.05 ± 1.44 | 5.30 ± 1.83 | 5.01 ± 1.13 | 0.464 |
| Cholesterol (mmol/L) | 6.15 ± 2.96 | 6.09 ± 2.91 | 6.27 ± 3.07 | 6.13 ± 3.01 | 5.43 ± 1.65 | 0.619 |
| Triglyceride (mmol/L) | 2.08 ± 1.78 | 1.95 ± 1.19 | 2.24 ± 2.25 | 2.06 ± 1.51 | 1.67 ± 1.16 | 0.254 |
| HDL-C (mmol/L) | 1.23 ± 0.42 | 1.23 ± 0.42 | 1.25 ± 0.43 | 1.19 ± 0.41 | 1.30 ± 0.52 | 0.485 |
| LDL-C (mmol/L) | 4.03 ± 2.32 | 4.09 ± 2.24 | 4.00 ± 2.40 | 4.05 ± 2.42 | 3.70 ± 1.51 | 0.896 |
| Uric acid (mmol/L) | 444.60 ± 130.67 | 440.35 ± 128.85 | 451.81 ± 139.30 | 447.75 ± 114.49 | 385.16 ± 103.30 | 0.132 |
| Blood urea nitrogen (mmol/L) | 6.80(4.93~11.13) | 6.08(4.70~8.80) | 7.72(5.10~13.01)* | 7.62(5.40~12.73)* | 5.71(4.26~7.41) | <0.001 |
| Serum creatinine (μmol/L) | 107.2(71.90~192.00) | 98.20(69.05~153.62) | 107.75(73.32~228.37) | 133.0(72.7~244.0)* | 78.65(58.75~128.10) | 0.018 |
| Homocysteine (μmol/L) | 15.60 ± 8.31 | 14.22 ± 6.80 | 17.67 ± 10.00* | 14.12 ± 6.14 | 14.13 ± 6.58 | <0.001 |
| Urinary sodium excretion (mmol/24 h) | 130.69 ± 80.60 | 127.70 ± 73.30 | 140.81 ± 90.10 | 110.17 ± 56.82 | 130.00 ± 98.81 | 0.098 |
| Proteinuria (g/24 h) | 1.73(0.46~4.55) | 1.39(0.39~3.87) | 1.94(0.46~5.04) | 2.09(0.96 ~5.36)* | 0.55(0.24~3.59) | 0.005 |
| Clinic-SBP (mmHg) | 140.25 ± 22.92 | 138.20 ± 22.22 | 140.56 ± 23.13 | 144.13 ± 24.48 | 136.82 ± 17.24 | 0.297 |
| Clinic-DBP (mmHg) | 85.38 ± 13.23 | 84.09 ± 13.07 | 86.03 ± 13.58 | 86.67 ± 13.25 | 83.59 ± 9.49 | 0.265 |
| 24 h-SBP (mmHg) | 129.05 ± 17.24 | 125.38 ± 15.41 | 129.80 ± 17.53* | 135.04 ± 18.54* | 125.45 ± 15.13 | <0.001 |
| 24 h-DBP (mmHg) | 77.80 ± 10.03 | 76.17 ± 9.72 | 78.26 ± 9.86 | 80.11 ± 10.85* | 76.36 ± 8.42 | 0.007 |
| SBP-daytime (mmHg) | 130.61 ± 17.19 | 128.23 ± 15.80 | 131.06 ± 17.71 | 134.15 ± 18.31* | 130.45 ± 15.53 | 0.035 |
| DBP-daytime (mmHg) | 78.96 ± 10.10 | 78.02 ± 10.04 | 79.25 ± 9.95 | 79.96 ± 10.86 | 79.50 ± 8.40 | 0.380 |
| SBP-nighttime (mmHg) | 121.00 ± 19.57 | 110.76 ± 13.70 | 123.43 ± 16.79* | 139.36 ± 19.95* | 99.27 ± 13.95* | <0.001 |
| DBP-nighttime (mmHg) | 71.77 ± 11.56 | 66.42 ± 9.32 | 73.14 ± 10.12* | 81.19 ± 11.62* | 60.09 ± 9.37* | <0.001 |
| Receiving no antihypertensive drugs | 147(25.0%) | 47(23.0%) | 76(29.7%) | 24(22.6%) | 0(0%) | 0.012 |
| Bedtime dosing of hypertensive drugs | 118(20.1%) | 40(19.6%) | 49(19.1%) | 21(19.8%) | 8(36.4%) | 0.394 |
| On RAS blockade | 341(58.0%) | 123(60.6%) | 142(55.5%) | 55(51.9%) | 21(95.4%)* | 0.002 |
| Calcium-channel blocker | 196(33.3%) | 67(33.0%) | 79(30.9%) | 44(41.5%) | 6(27.3%) | 0.152 |
| α-blocker | 46(7.8%) | 15(7.4%) | 20(7.8%) | 10(9.4%) | 1(4.5%) | 0.821 |
| β-blocker | 94(16.0%) | 33(16.3%) | 35(13.7%) | 25(23.6%) | 1(4.5%) | 0.037 |
| Statins | 103(17.5%) | 39(19.2%) | 45(17.6%) | 17(16.0%) | 2(9.1%) | 0.696 |
BMI: body mass index; CKD: chronic kidney disease; DBP: diastolic blood pressure; eGFR: estimated glomerular filtration rate; HDL-C: high-density lipoprotein cholesterol; iPTH: intact parathyroid hormone; LDL-C: low-density lipoprotein cholesterol; RAS: renin-angiotensin system; SBP: systolic blood pressure.
P-value for analysis of variance or χ2 test between 4 groups.
Choosing dippers as reference group, and comparing the 3 other groups (non-dipper, reverse-dipper, extreme dipper) to this group throughout. * indicated comparison with the dippers P < 0.017.