Table 2.
Characteristics of study sample at baseline and 2-week measurement
| Characteristic | Study sample at baselinea (n = 207) | Study sample at 2 weeksa (n = 179) |
|---|---|---|
| Sex, male, n (%) | 124 (59.9) | 107 (59.8) |
| Age (years), mean (SD) | 65.5 (13.8) | 66.1 (13.1) |
| Ethnocultural groupb, Dutch, n (%) | 176 (85.0) | 152 (84.9) |
| Educational levelc, n (%) | ||
| Low | 85 (41.0) | 74 (41.3) |
| Middle | 49 (23.7) | 43 (24.0) |
| High | 73 (35.3) | 62 (34.6) |
| Primary kidney disease, n (%) | ||
| Glomerulonephritis/sclerosis | 34 (16.6) | 33 (18.6) |
| Pyelonephritis | 7 (3.4) | 7 (4.0) |
| Polycystic kidney disease | 16 (7.8) | 15 (8.5) |
| Other congenital/hereditary kidney diseases | 15 (7.3) | 13 (7.3) |
| Hypertension/renal vascular disease | 46 (22.5) | 42 (23.7) |
| Diabetes mellitus | 14 (6.8) | 12 (6.8) |
| Miscellaneous | 63 (30.7) | 49 (27.7) |
| Unknown | 10 (4.9) | 6 (3.4) |
| Kidney function (eGFR), mean (SD) | 21.4 (6.7) | 21.6 (6.6) |
| KRT in medical historyd, yes, n (%) | 35 (17.0) | 30 (16.9) |
| BMI, mean (SD) | 26.8 (5.2) | 26.9 (5.2) |
| Smoking, n (%) | ||
| Yes | 25 (13.2) | 19 (11.7) |
| No, stopped | 94 (49.7) | 82 (50.6) |
| No, never smoked | 70 (37.0) | 61 (37.7) |
| Comorbidities, n (%) | ||
| Hypertension, yes | 164 (79.2) | 140 (78.2) |
| Diabetes mellitus, yes | 62 (30.0) | 53 (29.6) |
| CVD, yes | 53 (25.6) | 43 (24.0) |
| Lung disease, yes | 30 (14.5) | 28 (15.6) |
| Liver disease, yes | 11 (5.3) | 8 (4.5) |
| Malignancy, yes | 50 (24.2) | 43 (24.0) |
Missing values at baseline: primary kidney disease: n = 2 (1.0%); KRT in medical history: n = 1 (0.5%); BMI: n = 11 (5.3%); smoking: n = 18 (8.7%). Missing values at 2 weeks: primary kidney disease: n = 2 (1.1%); KRT in medical history: n = 1 (0.6%); BMI: n = 9 (5.0%); smoking: n = 17 (9.5%).
Study sample at baseline was used for validity analyses. Study sample at 2-week measurement was used for reliability analyses.
Self-reported ethnocultural group: ‘What ethnic group do you consider yourself to belong to?’
Educational level according to International Standard Classification of Education levels 2011, classified as low (primary, lower secondary, or lower vocational education), middle (upper secondary or upper vocational education), and high (tertiary education [college/university]).
KRT in medical history includes patients who have undergone (temporary) dialysis treatment or a kidney transplant in the past. At study inclusion, all patients had an eGFR < 30 mL/min/1.73 m2 and did not require dialysis treatment, in accordance with inclusion criteria.