Table 1.
Baseline participant characteristics stratified by baseline eGFR (n=550)
| Baseline factor | Observations, n | eGFR(CKD-EPI)<60 ml/min per 1.73 m2 (n=85) | eGFR (CKD-EPI) 60–89 ml/min per 1.73 m2 (n=125) | eGFR (CKD-EPI)≥90 ml/min per 1.73 m2 (n=340) | Participants with Follow-up Blood Samples (n=550) | Participants without Follow-up Blood Samples (n=46) | P Valuea |
|---|---|---|---|---|---|---|---|
| Age, yr | 550 | 60.1 (50.0–68.5) | 53.7 (44.1–63.5) | 39.6 (30.3–49.5) | 46.3 (34.8–56.5) | 32.4 (22.3–41.9) | <0.001 |
| Men | 550 | 36 (42.4) | 47 (37.6) | 117 (34.4) | 200 (36.4) | 21 (45.7) | 0.21 |
| Weight, kg | 548 | 76.4 (63.4–92.0) | 83.9 (71.6–98.0) | 82.7 (69.7–98.3) | 82.1 (68.8–97.4) | 73.6 (62.2–87.6) | 0.02 |
| BMI, kg/m2 | 546 | 27.8 (23.8–32.1) | 30.2 (26.6–34.5) | 30.0 (25.4–35.1) | 29.6 (25.3–34.8) | 25.7 (21.9–29.9) | 0.01 |
| Waist circumference, cm | 524 | 101.1 (93.5–112.9) | 103.3 (95.0–113.3) | 100.3 (88.4–111.8) | 101.6 (90.9–112.2) | 89.6 (77.5–101.7) | <0.001 |
| Waist-to-hip ratio | 520 | 1.00 (0.93–1.05) | 0.95 (0.90–1.03) | 0.93 (0.85–0.99) | 0.95 (0.87–1.01) | 0.87 (0.83–0.94) | <0.001 |
| Body surface area, m2b | 546 | 1.82 (1.68–2.00) | 1.93 (1.75–2.09) | 1.92 (1.75–2.08) | 1.90 (1.74–2.08) | 1.86 (1.72–2.00) | 0.10 |
| Diabetes | 550 | 57 (67.1) | 59 (47.2) | 125 (36.8) | 241 (43.8) | 6 (13.3) | <0.001 |
| Current smoker | 539 | 16 (19.8) | 32 (26.4) | 169 (50.1) | 217 (40.3) | 23 (51.1) | 0.16 |
| Systolic BP, mmHg | 542 | 120.0 (111.3–135.7) | 116.3 (106.0–129.7) | 114.2 (104.7–125.3) | 115.8 (106.0–128.0 | 108.8 (98.2–119.8) | 0.02 |
| Diastolic BP, mmHg | 542 | 73.7 (67.7–79.0) | 73.7 (67.3–80.3) | 74.5 (67.3–82.0) | 74.0 (67.3–81.3) | 69.8 (61.7–78.0) | 0.01 |
| HbA1c | |||||||
| Measured as mmol/mol)c | 536 | 47.5 (41.0–68.3) | 44.3 (39.9–57.4) | 42.1 (37.7–53.0) | 43.2 (37.7–56.3) | 38.3 (35.5–41.0) | <0.001 |
| Measured as percentage | 536 | 6.5 (5.9–8.4) | 6.2 (5.8–7.4) | 6.0 (5.6–7.0) | 6.1 (5.6–7.3) | 5.7 (5.4–5.9) | <0.001 |
| Cholesterol | |||||||
| Measured as mg/dl | 530 | 166.0 (142.8–189.1) | 173.7 (154.4–208.4) | 187.2 (162.1–216.2) | 181.4 (154.4–212.3) | 189.1 (158.3–220.0) | 0.10 |
| Measured as mmol/L | 530 | 4.3 (3.7–4.9) | 4.5 (4.0–5.4) | 4.9 (4.2–5.6) | 4.7 (4.0–5.5) | 4.9 (4.1–5.7) | 0.10 |
| HDL cholesterol | |||||||
| Measured as mg/dl | 519 | 34.7 (30.9–44.4) | 38.9 (34.7–46.3) | 38.6 (34.7–48.6) | 38.6 (33.6–46.3) | 46.3 (38.6–54.0) | 0.01 |
| Measured as mmol/L | 519 | 0.9 (0.8–1.2) | 1.0 (0.9–1.2) | 1.0 (0.9–1.3) | 1.0 (0.9–1.2) | 1.2 (1.0–1.4) | 0.01 |
| Cholesterol-to-HDL ratio | 519 | 4.2 (3.6–5.9) | 4.5 (3.7–5.7) | 4.6 (3.6–5.8) | 4.5 (3.6–5.8) | 4.2 (3.3–5.0) | 0.08 |
| Enzymatic creatinine | |||||||
| Measured as mg/dl | 532 | 1.70 (1.38–2.25) | 0.90 (0.81–1.05) | 0.68 (0.59–0.82) | 0.81 (0.64–0.99) | 0.79 (0.67–0.95) | 0.23 |
| Measured as µmol/La | 532 | 150 (122–199) | 80 (72–93) | 60 (52–73) | 72 (57–88) | 70 (59–84) | 0.23 |
| CKD-EPI eGFR, ml/min per 1.73 m2 | 544 | 37.7 (24.4–48.7) | 82.0 (74.5–90.7) | 107.6 (99.2–116.9) | 97.9 (79.3–111.7) | 111.8 (98.2–121.0) | <0.001 |
| Measured GFR, ml/min per 1.73 m2 | 516 | 46.2 (31.4–56.2) | 86.9 (73.8–98.4) | 114.2 (100.2–127.3) | 102.4 (82.6–120.8) | 112.5 (100.2–123.5 | 0.02 |
| CRP, mg/L | 527 | 5.0 (2.5–12.5) | 5.2 (3.0–10.0) | 6.0 (3.0–11.0) | 5.8 (3.0–11.0) | 5.0 (2.5–9.5) | 0.23 |
| Bilirubin | |||||||
| Measured as mg/dl ) | 543 | 0.29 (0.18–0.41) | 0.41 (0.29–0.53) | 0.35 (0.29–0.58) | 0.35 (0.23–0.53) | 0.47 (0.32–0.67) | 0.06 |
| Measured as µmol/L | 543 | 5.0 (3.0–7.0) | 7.0 (5.0–9.0) | 6.0 (5.0–10.0) | 6.0 (4.0–9.0) | 8.0 (5.5–11.5) | 0.06 |
| ACR | |||||||
| Measured as mg/g | 520 | 650.0 (146.9–1894.8) | 19.0 (7.1–122.1) | 12.4 (5.8–43.4) | 18.1 (6.2–151.8) | 4.4 (2.7–12.4) | <0.01 |
| Measured as mg/mmol | 520 | 73.5 (16.6–214.1) | 2.2 (0.8–13.8) | 1.4 (0.7–4.9) | 2.1 (0.7–17.2) | 0.5 (0.3–1.4) | <0.001 |
| ACR category | 520 | ||||||
| A1 | 6 (7.7) | 67 (56.8) | 224 (69.1) | 297 (57.1) | 34 (82.9) | 0.01 | |
| A2 | 21 (26.9) | 26 (22.0) | 67 (20.7) | 114 (21.9) | 4 (9.8) | ||
| A3 | 51 (65.4) | 25 (21.2) | 33 (10.2) | 109 (21.0) | 3 (7.3) | ||
| Use of ACE inhibitors | 550 | 51 (60.0) | 45 (36.0) | 69 (20.3) | 165 (30.0) | 2 (4.3) | <0.001 |
| Use of ARB | 550 | 23 (27.1) | 14 (11.2) | 19 (5.6) | 56 (10.2) | 3 (6.5) | 0.42 |
| Housing | |||||||
| Housing tenure | 541 | 0.66 | |||||
| Rent or other tenure | 77 (93.9) | 95 (77.9) | 296 (87.8) | 468 (86.5) | 4 (8.9) | ||
| Own/being purchased | 5 (6.1) | 27 (22.1) | 41 (12.2) | 73 (13.5) | 41 (91.1) | ||
| Education | |||||||
| Highest level of school completed | 534 | 0.04 | |||||
| Less than year 10/never went to school | 47 (58.8) | 50 (42.0) | 106 (31.6) | 203 (38.0) | 9 (20.0) | ||
| Year 10/equivalent | 19 (23.8) | 52 (43.7) | 142 (42.4) | 213 (39.9) | 21 (46.7) | ||
| Year 12/equivalent | 14 (17.5) | 17 (14.3) | 87 (26.0) | 118 (22.1) | 15 (33.3) |
Data are median (IQR) or n (%). CKD-EPI, CKD-Epidemiology Collaboration; BMI, body mass index; HbA1c, hemoglobin A1c; CRP, C-reactive protein; ACR, urine albumin-to-creatinine ratio; A1, albuminuria <27 mg/g (3 mg/mmol); A2, albuminuria, 27–265 mg/g (3–30 mg/mmol); A3, albuminuria>265 mg/g (30 mg/mmol); ACE, angiotensin-converting enzyme; ARB, angiotensin-receptor blockade.
The P value compares the group with follow-up blood samples to the group without follow-up blood samples and was calculated using ANOVA for continuous variables and chi-squared test between categorical variables. The difference between serum creatinine in the two participant groups was tested on the log serum creatinine level.
Calculated using the Dubois formula.
The difference between hemoglobin A1c (HbA1c) levels in the two participant groups was tested on the log HbA1c level.
For difference between participants with a follow-up blood sample and participants without a follow-up blood sample. Calculated using ANOVA for continuous variables and chi-squared test between categorical variables.