Table 2. Baseline characteristics of end-stage renal disease patients stratified according to serum potassium levels (N = 3,230).
| Variables | K<3.5 (n = 91) | 3.5≤ K <4.0 (n = 289) | 4.0≤ K <4.5 (n = 717) | 4.5≤ K <5.0 (n = 962) | K ≥5 (n = 1,171) | P-value |
|---|---|---|---|---|---|---|
| Age (years) | 70.0 [54.0–73.0] | 63.0 [51.0–73.5] | 63.0 [51.0–72.0] | 60.0 [49.3–69.0] | 59.0 [50.0–68.0] | <0.001† |
| Men (N, %) | 51 (56.0%) | 157 (54.3%) | 419 (58.4%) | 590 (61.3%) | 682 (58.2%) | 0.248‡ |
| BMI (kg/m2) | 22.0 [21.0–24.0] | 22.0 [20.0–25.0] | 23.0 [21.0–24.0] | 23.0 [21.0–25.0] | 23.0 [21.0–25.0] | 0.163† |
| SBP (mmHg) | 135 [124–149] | 133 [121–150] | 140 [122–152] | 140 [120–154] | 140 [127–156] | <0.001† |
| DBP (mmHg) | 72 [65–86] | 78 [67–89] | 77 [65–86] | 78 [69–84] | 79 [70–86] | <0.001† |
| Dialysis vintage (years) | 2.26 [0.65–6.53] | 2.81 [1.17–6.34] | 2.75 [1.25–5.63] | 2.87 [1.30–5.56] | 3.35 [1.50–6.81] | 0.044† |
| Incident dialysis (N, %) | 42 (46.2%) | 155 (53.6%) | 381 (53.1%) | 500 (52.0%) | 513 (43.8%) | <0.001‡ |
| Dialysis modality (HD, %) | 29 (31.9%) | 108 (37.4%) | 378 (52.7%) | 621 (64.6%) | 942 (80.4%) | <0.001‡ |
| Primary renal disease (N, %) | 0.068‡ | |||||
| Diabetes | 39 (42.9%) | 116 (40.1%) | 291 (40.6%) | 434 (45.1%) | 510 (43.6%) | |
| Hypertension | 10 (11.0%) | 47 (16.3%) | 139 (19.4%) | 162 (16.8%) | 190 (16.2%) | |
| Glomerulonephritis | 8 (8.8%) | 30 (10.4%) | 96 (13.4%) | 127 (13.2%) | 157 (13.4%) | |
| Others | 34 (37.4%) | 96 (33.2%) | 191 (26.6%) | 239 (24.8%) | 314 (26.8%) | |
| MCCI | 6.0 [4.0–8.0] | 6.0 [4.0–8.0] | 5.0 [3.0–7.0] | 5.0 [3.0–7.0] | 5.0 [3.0–7.0] | 0.019† |
| > High school (N, %) | 57 (62.6%) | 172 (59.5%) | 414 (57.7%) | 625 (65.0%) | 755 (64.5%) | 0.014‡ |
| Smoking experience (N, %) | 30 (34.5%) | 97 (36.5%) | 275 (39.4%) | 374 (40.0%) | 429 (38.2%) | 0.700‡ |
| Laboratory data | ||||||
| Potassium (mmol/L) | 3.3 [3.1–3.4] | 3.8 [3.6–3.9] | 4.3 [4.2–4.4] | 4.7 [4.6–4.9] | 5.3 [5.1–5.6] | <0.001† |
| Hemoglobin (g/dL) | 9.0 [8.0–11.0] | 10.0 [9.0–11.0] | 10.0 [9.0–11.0] | 10.0 [8.0–11.0] | 10.0 [8.0–11.0] | 0.693† |
| Albumin (g/dL) | 3.0 [3.0–4.0] | 4.0 [3.0–4.0] | 4.0 [3.0–4.0] | 4.0 [3.0–4.0] | 4.0 [3.0–4.0] | <0.001† |
| Alkaline phosphatase (IU/L) | 80 [50–121] | 106 [62–199] | 95 [69–154] | 89 [61–128] | 83 [64–117] | 0.026† |
| Uric acid (mg/dL) | 7.0 [5.0–9.0] | 7.0 [6.0–8.0] | 7.0 [6.0–9.0] | 8.0 [6.0–9.0] | 8.0 [7.0–9.0] | <0.001† |
| Total cholesterol (mg/dL) | 147 [117–194] | 155 [130–194] | 156 [129–191] | 154 [127–183] | 157 [134–189] | 0.084† |
| hs-CRP (mg/dL) | 0.0 [0.0–2.0] | 0.0 [0.0–1.0] | 0.0 [0.0–1.0] | 0.0 [0.0–1.0] | 0.0 [0.0–1.0] | <0.001† |
| Medication (N, %) | ||||||
| ARB or ACEI | 17 (48.6%) | 74 (57.4%) | 197 (59.0%) | 247 (55.0%) | 287 (61.1%) | 0.299‡ |
| Diuretics | 17 (48.6%) | 79 (61.2%) | 196 (58.7%) | 234 (52.3%) | 257 (54.8%) | 0.227‡ |
| Residual renal function | 6.8 [4.1–12.5] | 6.1 [3.7–13.3] | 8.8 [4.9–15.0] | 8.9 [4.7–15.2] | 8.0 [4.1–15.2] | 0.276† |
| SGA (malnourished, N, %) | 24 (26.4%) | 67 (23.2%) | 174 (24.3%) | 204 (21.2%) | 238 (20.3%) | 0.226‡ |
| Death | 42 (46.2%) | 95 (32.9%) | 197 (27.5%) | 206 (21.4%) | 211 (18.0%) | <0.001‡ |
| Follow up duration (years) | 3.5 [3.1–4.0] | 4.0 [3.8–4.2] | 4.2 [4.1–4.3] | 4.5 [4.4–4.6] | 4.6 [4.5–4.7] | <0.001† |
Abbreviations: BMI, body mass index; SBP, systolic blood pressure; DBP, diastolic blood pressure; HD, hemodialysis; MCCI, modified Charlson comorbidity index; ARB, angiotensin receptor blocker; ACEI, angiotensin converting enzyme inhibitor; SGA, subjective global assessment.
† Kruskal Wallis test was applied for continuous nonparametric variables.
‡ The Chi-square test was applied for categorical nonparametric variables.