Table 2. Baseline Characteristics of Subjects Compared Among Those with Different Functional Status (n = 7,664).
| Total | Levels of Functional Disability | |||||
|---|---|---|---|---|---|---|
| Variables | Value | n | Mild/None (n = 3,192) | Moderate (n = 2,935) | Severe (n = 1,537) | p-value* |
| Demographic and clinical characteristics | ||||||
| Age, years | 69 (59–77) | 7,664 | 66 (57–75) | 71 (61–78) | 71 (62–79) | <0.001 |
| Sex, female, % | 36.1 | 7,664 | 32.3 | 39.2 | 38.1 | <0.001 |
| Body mass index, kg/m2 | 22.5 (20.3–25.2) | 5,489 | 22.7 (20.4–25.2) | 22.6 (20.2–25.3) | 22.3 (19.8–25.1) | 0.006 |
| Cause of end-stage kidney disease | 7,024 | <0.001 | ||||
| Chronic glomerulonephritis, % | 26.6 | - | 30.7 | 24.7 | 21.5 | - |
| Diabetic nephropathy, % | 48.1 | - | 46.8 | 50.2 | 47.2 | - |
| Glomerulosclerosis, % | 13.3 | - | 12.0 | 14.0 | 14.4 | - |
| Rapid progressive glomerulonephritis, % | 1.8 | - | 1.1 | 1.8 | 3.6 | - |
| Others, % | 10.2 | - | 9.5 | 9.5 | 13.4 | - |
| Systolic blood pressure, mmHg | 153 (136 to 170) | 6,828 | 154 (138–170) | 154 (136–172) | 150 (130–169) | <0.001 |
| Co-morbid conditions | ||||||
| Congestive heart failure, % | 28.6 | 7,391 | 18.8 | 32.8 | 40.6 | <0.001 |
| Ischemic heart disease, % | 9.7 | 7,570 | 7.6 | 11.0 | 12.1 | <0.001 |
| Stroke, % | 19.7 | 7,588 | 14.3 | 23.4 | 23.8 | <0.001 |
| Diabetes mellitus, % | 50.7 | 7,568 | 48.6 | 53.2 | 50.4 | 0.002 |
| Malignancy, % | 7.1 | 7,550 | 5.3 | 8.7 | 7.9 | <0.001 |
| Hemiplegia, % | 6.2 | 7,516 | 3.0 | 7.8 | 9.5 | <0.001 |
| Dementia, % | 9.5 | 7,489 | 4.0 | 12.1 | 16.0 | <0.001 |
| Liver disease, % | 7.2 | 7,516 | 5.9 | 8.3 | 7.6 | 0.001 |
| Past history of amputation, % | 1.8 | 6,890 | 1.4 | 2.3 | 1.9 | 0.046 |
| Dialysis | ||||||
| Late referral to nephrologist, %† | 51.5 | 6,949 | 48.9 | 51.5 | 57.3 | <0.001 |
| Type of vascular access | 7,430 | <0.001 | ||||
| Arteriovenous fistula, % | 51.4 | - | 61.9 | 48.9 | 34.4 | - |
| Temporary catheter, % | 33.9 | - | 22.2 | 37.4 | 51.7 | - |
| Others, % | 14.7 | - | 15.9 | 13.7 | 13.9 | - |
| Treatment time, hours | 3.5 (3.0–4.0) | 6,153 | 3.5 (3.0–4.0) | 3.5 (3.0–4.0) | 3.02 (3.0–4.0) | 0.02 |
| Laboratory data | ||||||
| Albumin, g/dL | 3.3 (2.8–3.7) | 6,797 | 3.4 (3.0–3.8) | 3.2 (2.8–3.6) | 3.1 (2.6–3.5) | <0.001 |
| Hemoglobin, g/dL | 8.3 (7.3–9.4) | 7,278 | 8.4 (7.4–9.5) | 8.2 (7.3–9.3) | 8.3 (7.3–9.4) | <0.001 |
| Estimated glomerular filtration rate, ml/min/1.73 m2§ | 4.8 (3.7 to 6.4) | 6,583 | 4.63 (3.59–6.00) | 4.85 (3.68–6.62) | 4.91 (3.78–6.89) | <0.001 |
| C-reaction protein, mg/dL | 0.36 (0.10–1.96) | 5,920 | 0.20 (0.08–0.80) | 0.44 (0.10–2.16) | 1.13 (0.20–4.79) | <0.001 |
| Calcium, mg/dL‡ | 8.7 (8.1–9.2) | 6,559 | 8.6 (8.0–9.1) | 8.8 (8.2–9.3) | 8.8 (8.3–9.4) | <0.001 |
| Phosphorus, mg/dL | 5.6 (4.6–6.8) | 6,848 | 5.6 (4.6–6.8) | 5.5 (4.5–6.7) | 5.7 (4.5–7.0) | 0.02 |
Note: Values for categorical variables are given as numbers (percentage) and continuous variables are given as medians and interquartile ranges (IQR).
†: Late referral was defined as 90 days or less from the first day of visit to the initiation of dialysis.
§: Estimated glomerular filtration rate was calculated from the formula for Japanese as follows: 194 × [serum creatinine, mg/dL]−1.094 × [age, years]−0.287, and × 0.739 if female
‡: Albumin-adjusted value was used: calcium + 4.0 –albumin (if albumin level <4.0 g/dL). Conversion factors for units: calcium in mg/dl to mmol/L, ×88.4; phosphorus in mg/dl to mmol/L, ×0.3229.
*To test the difference of distribution in for each variable among those within the three different levels of functional disability, we used the χ2 tests for categorical variables (%) and the Kruskal-Wallis test for continuous variables.