Table 1.
Characteristics of dialysis patients, stratified by presence of itching (yes/no) at baseline
| Characteristics | Total dialysis population (n = 2978) | Patients with itching [n = 1493 (50.1%)] | Patients without itching [n = 1485 (49.9%)] |
|---|---|---|---|
| Age (years), mean (SD) | 67.3 (14.1) | 67.4 (14.0) | 67.3 (14.2) |
| Sex (male), n (%) | 1827 (61.4) | 927 (62.1) | 900 (60.7) |
| SES, n (%) | |||
| Low | 1430 (48.4) | 711 (48.0) | 719 (48.8) |
| Middle | 907 (30.7) | 435 (29.4) | 472 (32.1) |
| High | 617 (20.9) | 336 (22.7) | 281 (19.1) |
| Primary kidney disease, n (%) | |||
| Glomerulonephritis/sclerosis | 333 (11.2) | 160 (10.7) | 173 (11.7) |
| Pyelonephritis | 140 (4.7) | 68 (4.6) | 72 (4.9) |
| Polycystic kidney disease | 171 (5.7) | 86 (5.8) | 85 (5.7) |
| Hypertension/renal vascular disease | 809 (27.2) | 411 (27.5) | 398 (26.8) |
| Diabetes mellitus type ½ | 601 (20.2) | 320 (21.4) | 281 (18.9) |
| Miscellaneous | 535 (18.0) | 257 (17.2) | 278 (18.7) |
| Unknown | 387 (13.0) | 191 (12.8) | 196 (13.2) |
| Dialysis modality, n (%) | |||
| HD | 2583 (87.9) | 1258 (85.6) | 1325 (90.1) |
| PD | 357 (12.1) | 212 (14.4) | 145 (9.9) |
| Dialysis sessions per week (HD), n (%) | |||
| <3 | 266 (12.8) | 125 (12.3) | 141 (13.2) |
| 3 | 1672 (80.3) | 817 (80.6) | 855 (80.1) |
| >3 | 144 (6.9) | 72 (7.1) | 72 (6.7) |
| Dialysis hours per week (HD), mean (SD) | 11.2 (4.3) | 11.1 (3.8) | 11.4 (4.8) |
| Time since dialysis initiation (months), median (IQR) | 15 (3–43) | 14 (3–41) | 17 (3–46) |
| Kidney transplantation in past (yes), n (%) | 327 (11.2) | 162 (11.1) | 165 (11.3) |
| rGFR (mL/min/1.73m2), median (IQR) | 4.7 (2.0–7.6) | 5.0 (2.0–8.0) | 4.5 (2.1–7.1) |
| Single-pool Kt/V in HD, mean (SD) | 1.47 (0.53) | 1.46 (0.54) | 1.48 (0.52) |
| Total Kt/V in PD, mean (SD) | 2.63 (1.06) | 2.70 (1.10) | 2.52 (0.99) |
| Haemoglobin (mmol/L), mean (SD) | 6.8 (0.9) | 6.8 (0.9) | 6.8 (0.9) |
| Ferritin (µg/L), median (IQR) | 318 (168–534) | 300 (153–517) | 330 (187–547) |
| Transferrin saturation (%), mean (SD) | 22.3 (10.5) | 21.8 (10.4) | 22.8 (10.6) |
| Calcium (mmol/L)a, mean (SD) | 2.31 (0.19) | 2.31 (0.19) | 2.31 (0.18) |
| Phosphate (mmol/L), mean (SD) | 1.59 (0.48) | 1.62 (0.49) | 1.57 (0.47) |
| Parathyroid hormone (pmol/L), median (IQR) | 30 (17–51) | 30 (17–52) | 30 (17–50) |
| Symptom burden | |||
| Total number of symptoms (0–30), mean (SD) | 11.0 (6.4) | 13.7 (6.2) | 8.3 (5.3) |
| Total symptom burden score (0–150), median (IQR) | 27 (14–42) | 35 (23–51) | 19 (10–32) |
| Dry skin (yes), n (%) | 1726 (58.0) | 1091 (73.1) | 635 (42.8) |
| Sleep problems, n (%) | |||
| Sleep problems (yes)b | 1816 (61.0) | 1044 (69.9) | 772 (52.0) |
| Trouble falling asleep (yes) | 1312 (44.1) | 798 (53.4) | 514 (34.6) |
| Trouble staying asleep (yes) | 1549 (52.0) | 907 (60.8) | 642 (43.2) |
| Psychological symptoms, n (%) | |||
| Psychological symptoms (yes)c | 820 (27.5) | 534 (35.8) | 286 (19.3) |
| Worrying (yes) | 1195 (40.1) | 708 (47.4) | 487 (32.8) |
| Feeling nervous (yes) | 816 (27.4) | 517 (34.6) | 299 (20.1) |
| Feeling irritable (yes) | 843 (28.3) | 558 (37.4) | 285 (19.2) |
| Feeling sad (yes) | 1088 (36.5) | 669 (44.8) | 419 (28.2) |
| Feeling anxious (yes) | 647 (21.7) | 425 (28.5) | 222 (14.9) |
Missing values: age, n = 3 (0.10%); sex, n = 2 (0.07%); SES, n = 24 (0.81%); primary kidney disease, n = 2 (0.07%); dialysis modality, n = 38 (1.29%); dialysis sessions per week (HD), n = 501 (19.4%); dialysis hours per week (HD), n = 505 (19.6%); time since dialysis initiation, n = 58 (1.99%); kidney transplantation in past, n = 58 (1.99%); residual GFR, n = 1977 (66.4%); single-pool Kt/V in HD, n = 647 (25.0%); total Kt/V in PD, n = 221 (61.9%); haemoglobin, n = 286 (9.60%); ferritin, n = 416 (14.0%); transferrin saturation, n = 993 (33.3%); calcium, n = 369 (12.4%); phosphate, n = 280 (9.40%); parathyroid hormone, n = 522 (17.5%).
Albumin-adjusted calcium.
Sleep problems are considered present if at least one of the two symptoms are experienced by the patient.
cPsychological symptoms are considered present if three of the five symptoms are experienced by the patient.