Table 1.
Patient characteristics at the start of the first 91-day dialysis treatment period after initiation of dialysis, by modality, and total proportion of variables with missing information.
| Ever treated with extended-hours hemodialysis (N=1206) |
Exclusively treated with conventional hemodialysis (N=111,707) |
Others (N=23,294) |
% Missing | |
|---|---|---|---|---|
| Age, years | 0 | |||
| 18–24 | 3 | 1 | 2 | |
| 25–44 | 28 | 11 | 18 | |
| 45–59 | 42 | 27 | 30 | |
| 60–74 | 24 | 36 | 33 | |
| ≥75 | 3 | 24 | 16 | |
| Race, % | 0 | |||
| Asian | 3 | 3 | 4 | |
| Black | 37 | 31 | 21 | |
| White | 47 | 47 | 58 | |
| Hispanic | 10 | 15 | 13 | |
| Other | 3 | 4 | 3 | |
| Male, % | 70 | 57 | 56 | 0 |
| Primary Health Insurance,% | 0 | |||
| Medicare | 35 | 53 | 46 | |
| Medicaid | 7 | 7 | 5 | |
| Other insurance | 58 | 40 | 48 | |
| Geographic Location | 0 | |||
| Northeast, % | 9 | 13 | 12 | |
| Midwest, % | 30 | 18 | 19 | |
| West, % | 40 | 25 | 41 | |
| South, % | 21 | 44 | 28 | |
| Year of Incidence | 0 | |||
| 2007 | 25 | 20 | 20 | |
| 2008 | 24 | 20 | 21 | |
| 2009 | 24 | 21 | 22 | |
| 2010 | 18 | 21 | 22 | |
| 2011 | 9 | 18 | 15 | |
| Co-existing illnesses, % | 0 | |||
| Atherosclerotic Heart Disease |
21 | 14 | 18 | |
| Congestive Heart Failure | 55 | 37 | 30 | |
| Diabetes | 68 | 58 | 63 | |
| Other Cardiovascular | 19 | 15 | 16 | |
| Access Type, %a | 6.5 | |||
| Arteriovenous fistula or graft |
24 | 20 | 11 | |
| Central venous catheter | 73 | 80 | 46 | |
| Peritoneal dialysis catheter |
3 | 0 | 42 | |
| Treatment parametersa | ||||
| Body mass index | 32.5±9.5 | 28.2±7.4 | 28.3±7.2 | 8.7 |
| Pre-dialysis systolic blood pressure, mm Hg |
152±18 | 147±19 | 148±19 | 5.9 |
| Weekday inter-dialytic weight gain, % |
2.2 [1.5,3.0] | 2.3 [1.5,3.2] | 0.02 [0.013, 0.029] | 9.3 |
| Weekend inter-dialytic weight gain, % |
2.8 [2.0,4.1] | 3.1 [2.1, 4.2] | 0.027 [0.017, 0.038] | 8.9 |
| Laboratory Variables | ||||
| Serum albumin, g/dL | 3.6±0.5 | 3.5±0.5 | 3.6±0.5 | 1.6 |
| Alkaline phosphatase, u/L* |
87 [69, 111] | 87 [69, 115] | 82 [65, 106] | 1.8 |
| Serum calcium, mg/dL | 9.1±0.6 | 9.1±0.6 | 9.1±0.6 | 1.5 |
| Serum ferritin, ng/mL | 234 [138, 373] | 282 [164, 484] | 237 [133, 413] | 2.8 |
| Hemoglobin, g/dL* | 11.1±1.2 | 11.1±1.2 | 11.3±1.2 | 1.3 |
| Serum iron saturation, % | 21 [17,25] | 22 [17, 27] | 23 [18, 29] | 2.1 |
| Parathyroid hormone, pg/mL |
378 [240, 569] | 314 [197, 486] | 294 [183, 470] | 2.0 |
| Serum phosphorous, mg/dL |
5.3±1.2 | 4.9±1.2 | 4.9±1.1 | 1.5 |
| spKt/V urea | 1.4 [1.2, 1.8] | 1.6 [1.4, 1.8] | 1.4 [1.2, 1.7] | 8.2 |
| Parenteral medications | ||||
| Cumulative iron, mg/month |
1062 [525,1600] | 1000 [400, 1400] | 400 [0, 1050] | 0 |
| Erythropoietin Dose, median units/week |
26,950 [16,500, 36,300] |
24,900 [13,200, 33,000] |
17,600 [9,000, 29,700] |
0 |
Summary statistics are mean ± SD, median and interquartile range, or proportions (%).
*
P>0.05 for the difference between extended-hours and conventional hemodialysis groups using ANOVA, Kruskal-Wallis test, or Chi-squared test. P<0.05 for all other comparisons.
a
Among patients ever-treated with extended hours hemodialysis, 67% were treated with conventional hemodialysis in the first 91-day period. Values for the period prior to extended-hours hemodialysis are available in Supplementary Table S1.