Table 1.
Baseline characteristics of the study population by stage of CKD
| n | Overall cohort | Stages 1–2a | Stage 3a | Stages 4–5a | P-value | |
|---|---|---|---|---|---|---|
| Demographic | ||||||
| Age (years, mean (SD) | 510 | 57.1 (18.3) | 48.1 (15.5) | 59.3 (16.8) | 65.5 (17.1) | <0.001 |
| Men (%) | 293 | 55.3 | 55.6 | 59.8 | 56.0 | 0.706 |
| Race (%) | ||||||
| White Irish | 492 | 92.8 | 91.4 | 96.6 | 96.4 | 0.049 |
| White Irish traveller | 2 | 0.4 | 0.7 | 0.0 | 0.0 | 0.055 |
| White other | 12 | 2.3 | 1.4 | 2.8 | 2.9 | 0.050 |
| Asian | 2 | 0.4 | 0.7 | 0.6 | 0.0 | 0.053 |
| Other | 9 | 1.7 | 5.7 | 0.0 | 0.7 | 0.054 |
| Cause of CKD (%) | ||||||
| Hypertension | 144 | 27.2 | 22.9 | 24.6 | 34.8 | 0.055 |
| Diabetes | 67 | 12.6 | 8.3 | 15.1 | 17.0 | 0.064 |
| Glomerulonephritis | 94 | 17.7 | 24.3 | 14.5 | 14.9 | 0.047 |
| Autosomal dominant PKD | 33 | 6.2 | 4.9 | 8.9 | 5.0 | 0.267 |
| Hereditary | 14 | 2.6 | 3.5 | 3.4 | 0.7 | 0.261 |
| Other | 172 | 32.5 | 0.0 | 0.0 | 0.0 | 0.610 |
| Not known | 71 | 13.4 | 11.1 | 10.1 | 16.3 | 0.233 |
| Kidney biopsy (%) | 79 | 14.9 | 19.4 | 14.5 | 13.5 | 0.348 |
| Comorbid conditions (%) | ||||||
| Diabetes | 111 | 20.9 | 17.4 | 24.1 | 28.3 | 0.117 |
| Hypertension | 382 | 72.1 | 73.6 | 80.1 | 84.1 | 0.116 |
| Cancer | 34 | 6.4 | 7.4 | 8.4 | 6.5 | 0.820 |
| Heart failure | 22 | 4.2 | 1.7 | 4.2 | 7.2 | 0.111 |
| Thyroid disease | 49 | 9.2 | 5.8 | 12.0 | 13.0 | 0.107 |
| Stroke/TIA | 22 | 4.2 | 3.3 | 4.2 | 6.5 | 0.490 |
| COPD | 22 | 4.2 | 3.3 | 4.2 | 5.8 | 0.609 |
| Peripheral vascular disease | 38 | 7.2 | 3.3 | 10.2 | 10.9 | 0.042 |
| Coronary heart disease | 76 | 14.3 | 9.1 | 15.8 | 23.9 | 0.004 |
| Obesity | 29 | 5.5 | 4.1 | 4.8 | 8.7 | 0.262 |
| Gout | 59 | 11.1 | 5.7 | 15.2 | 15.9 | 0.013 |
| Hypercholesterolaemia | 131 | 24.7 | 23.0 | 30.3 | 32.4 | 0.209 |
| Depression | 20 | 3.8 | 5.0 | 3.6 | 5.1 | 0.799 |
| Arthritis | 29 | 5.5 | 5.0 | 7.2 | 4.3 | 0.538 |
| Osteoporosis | 31 | 5.8 | 5.8 | 9.6 | 2.9 | 0.050 |
| Current or ex-smoker | 53 | 10.0 | 12.4 | 12.0 | 8.7 | 0.572 |
| Physical measurements, mean (SD) | ||||||
| Weight (kg) | 408 | 80.6 (17.4) | 79.8 (15.8) | 79.8 (17.5) | 82.0 (19.4) | 0.445 |
| Pulse | 301 | 75.1 (16.2) | 75.6 (13.1) | 73.6 (13.4) | 75.7 (19.2) | 0.920 |
| Systolic BP (mmHg) | 495 | 137.7 (19.6) | 131.7 (16.6) | 138.8 (19.0) | 141.5 (21.7) | <0.001 |
| Diastolic BP (mmHg) | 495 | 77.5 (13.3) | 78.7 (13.7) | 77.6 (12.9) | 76.7 (12.3) | 0.221 |
| Laboratory parameters, mean (SD) | ||||||
| eGFR (mL/min/1.73m2) | 464 | 48.5 (27.9) | 82.7 (19.4) | 43.5 (8.3) | 19.9 (6.1) | <0.001 |
| Haemoglobin (g/dL) | 461 | 12.6 (1.9) | 13.5 (1.7) | 12.7 (1.8) | 11.6 (1.7) | <0.001 |
| Ferritin (ng/L) | 163 | 251.6 (334.6) | 244.7 (401.2) | 174.4 (195.0) | 311.7 (366.0) | 0.326 |
| TSAT ratio (%) | 132 | 26.6 (13.2) | 27.4 (11.4) | 29.6 (15.9) | 25.2 (12.6) | 0.443 |
| Folate (nmol/L) | 97 | 39.6 (142.3) | 63.2 (189.5) | 10.1 (6.3) | 27.9 (113.9) | 0.230 |
| Vitamin B12 (nmol/L) | 124 | 451.5 (271.1) | 418.9 (201.0) | 480.1 (404.1) | 471.4 (189.9) | 0.386 |
| Calcium (mmol/L) | 417 | 2.4 (0.2) | 2.4 (0.2) | 2.4 (0.1) | 2.3 (0.2) | <0.001 |
| Albumin (g/L) | 364 | 41.1 (5.6) | 42.4 (5.6) | 41.6 (5.0) | 39.3 (6.2) | <0.001 |
| Phosphate (mmol/L) | 388 | 1.1 (0.3) | 1.0 (0.2) | 1.1 (0.2) | 1.3 (0.3) | <0.001 |
| PTH (pg/mL) | 166 | 131.7 (128.6) | 70.4 (42.8) | 107.5 (126.8) | 157.4 (133.7) | 0.001 |
| Total cholesterol (mmol/L) | 199 | 4.6 (1.4) | 4.9 (1.4) | 4.6 (1.0) | 4.4 (1.6) | 0.053 |
| LDL cholesterol (mmol/L) | 126 | 2.6 (1.2) | 2.8 (1.3) | 2.4 (0.7) | 2.5 (1.5) | 0.293 |
| HDL cholesterol (mmol/L) | 128 | 1.4 (0.5) | 1.4 (0.5) | 1.5 (0.5) | 1.3 (0.4) | 0.591 |
| Triglycerides (mmol/L) | 196 | 3.9 (21.2) | 1.8 (1.4) | 4.4 (23.2) | 5.5 (28.2) | 0.376 |
| HbA1c (mmol/mol) | 89 | 48.4 (23.4) | 47.5 (15.1) | 43.4 (14.3) | 49.1 (27.0) | 0.904 |
| Urine tests | ||||||
| Protein:creatinine ratio | 139 | 139.3 (246.6) | 49.0 (71.3) | 157.5 (344.8) | 210.6 (223.6) | 0.002 |
| Albumin:creatinine ratio | 53 | 101.4 (211.3) | 22.7 (28.1) | 93.4 (239.2) | 205.9 (270.6) | 0.019 |
| Medications | ||||||
| ACE-I | 121 | 22.8 | 26.4 | 25.7 | 16.3 | 0.066 |
| ARB | 96 | 18.1 | 18.8 | 20.1 | 18.4 | 0.921 |
| ACE-I and ARB | 12 | 2.3 | 2.1 | 3.9 | 0.7 | 0.164 |
| Aspirin | 181 | 34.2 | 25.0 | 34.1 | 45.4 | 0.001 |
| Iron therapy (oral or i.v.) | 54 | 10.2 | 2.1 | 8.9 | 19.1 | <0.001 |
| ESA therapy | 25 | 4.7 | 0.7 | 3.4 | 12.1 | <0.001 |
PKD, polycystic kidneys; TIA, transient ischaemic attack; COPD, chronic obstructive pulmonary disease; BP, blood pressure; LDL, low-density lipoprotein; HDL, high-density lipoprotein; ACE-I, angiotensin-converting enzyme inhibitor; ARB, angiotensin receptor blocker. ESA, erythropoietin stimulating agent
a
eGFR (estimated glomerular filtration rate per CKD-EPI equation) was available for 464 patients .