Table 1.
Baseline characteristics of 98,577 hemodialysis patients stratified by change in pulse pressure
| Variables | All | ∆PP (mmHg) | P Value | ||||||
|---|---|---|---|---|---|---|---|---|---|
| <–25 | ≥–25 to <–15 | ≥–15 to <–5 | ≥–5 to <5 | 5 to <15 | 15 to <25 | ≥25 | |||
| n (%) | 98,577 (100) | 9038 (9) | 12,958 (13) | 24,424 (25) | 27,200 (28) | 15,406 (16) | 6177 (6) | 3374 (3) | |
| Age (y) | 62±15 | 63±14 | 62±14 | 62±15 | 61±16 | 62±16 | 63±15 | 63±15 | 0.04 |
| Women | 45 | 50 | 47 | 44 | 42 | 44 | 46 | 49 | <0.001 |
| Race/ethnicity | |||||||||
| White | 42 | 44 | 42 | 41 | 41 | 43 | 46 | 45 | 0.001 |
| Black | 33 | 31 | 32 | 33 | 34 | 33 | 31 | 34 | 0.02 |
| Hispanic | 15 | 15 | 15 | 15 | 15 | 14 | 14 | 14 | 0.01 |
| Asian | 3 | 3 | 4 | 3 | 3 | 3 | 3 | 2 | <0.001 |
| Others | 7 | 7 | 7 | 8 | 7 | 7 | 6 | 5 | <0.001 |
| HD duration | |||||||||
| 3 to <6 mo | 57 | 56 | 54 | 55 | 57 | 60 | 63 | 65 | <0.001 |
| 6 to <24 mo | 18 | 19 | 19 | 19 | 18 | 17 | 16 | 15 | <0.001 |
| 2 to <5 y | 16 | 17 | 18 | 17 | 16 | 15 | 14 | 13 | <0.001 |
| ≥5 y | 9 | 8 | 9 | 9 | 9 | 8 | 7 | 7 | <0.001 |
| Comorbidities | |||||||||
| DM | 59 | 68 | 64 | 58 | 55 | 58 | 60 | 62 | <0.001 |
| IHD | 22 | 22 | 21 | 21 | 21 | 22 | 24 | 24 | <0.001 |
| Cancer | 4.6 | 4.1 | 4.1 | 4.4 | 4.6 | 5 | 4.9 | 5.3 | <0.001 |
| CHF | 28 | 29 | 28 | 27 | 27 | 28 | 31 | 30 | 0.002 |
| COPD | 6 | 6 | 6 | 6 | 6 | 6 | 7 | 6 | 0.01 |
| CVD | 7 | 8 | 8 | 7 | 7 | 8 | 8 | 8 | 0.43 |
| Hypertension | 80 | 83 | 82 | 80 | 79 | 80 | 81 | 83 | 0.001 |
| Other cardiac diseases | 6 | 5 | 5 | 5 | 6 | 6 | 6 | 6 | <0.001 |
| PVD | 11 | 13 | 12 | 11 | 11 | 12 | 13 | 13 | 0.20 |
| Nonambulatory state | 2.8 | 2.7 | 2.6 | 2.7 | 2.8 | 3.3 | 3 | 3.4 | <0.001 |
| Current smoking | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 0.15 |
| Insurance | |||||||||
| Medicare | 68 | 69 | 69 | 68 | 68 | 69 | 69 | 69 | 0.23 |
| Medicaid | 6 | 5 | 5 | 6 | 6 | 6 | 6 | 6 | <0.001 |
| Private | 9 | 4 | 9 | 12 | 12 | 7 | 4 | 1 | <0.001 |
| Others | 17 | 22 | 17 | 14 | 14 | 18 | 21 | 24 | 0.01 |
| Vascular access | |||||||||
| AVF | 30 | 29 | 31 | 31 | 30 | 28 | 25 | 25 | <0.001 |
| AVG | 31 | 30 | 33 | 33 | 32 | 29 | 27 | 24 | <0.001 |
| Catheter | 39 | 41 | 36 | 36 | 38 | 43 | 48 | 51 | <0.001 |
| Pre-HD BP (mmHg) | |||||||||
| Systolic BP | 151±24 | 172±22 | 162±21 | 153±22 | 146±23 | 143±24 | 140±24 | 137±23 | <0.001 |
| Diastolic BP | 78±15 | 80±16 | 80±15 | 78±14 | 77±14 | 77±15 | 77±16 | 77±17 | <0.001 |
| PP | 73±17 | 92±15 | 82±15 | 75±15 | 69±15 | 66±16 | 64±16 | 60±16 | <0.001 |
| Mean arterial BP | 102±17 | 110±17 | 107±16 | 103±15 | 100±16 | 99±17 | 98±17 | 97±18 | <0.001 |
| Post-HD BP (mmHg) | |||||||||
| Systolic BP | 141±23 | 129±19 | 134±20 | 136±21 | 141±22 | 149±24 | 157±24 | 164±24 | <0.001 |
| Diastolic BP | 73±14 | 72±14 | 72±13 | 72±13 | 73±13 | 74±15 | 74±16 | 73±17 | <0.001 |
| Pulse pressure | 68±17 | 57±15 | 62±15 | 64±15 | 68±15 | 75±16 | 83±16 | 91±16 | <0.001 |
| Mean arterial BP | 95±16 | 91±14 | 92±14 | 93±14 | 96±15 | 99±17 | 102±17 | 103±18 | <0.001 |
| ∆PP (mmHg) | −5±16 | −35±7 | −20±3 | −10±3 | −1±3 | 9±3 | 19±3 | 31±5 | <0.001 |
| Time on dialysis (min) | 214±28 | 214±28 | 214±28 | 215±28 | 214±28 | 214±27 | 214±28 | 213±28 | 0.35 |
| Ultrafiltration (kg/session) | 2.6±1.2 | 2.9±1.3 | 2.8±1.2 | 2.7±1.2 | 2.6±1.2 | 2.5±1.2 | 2.4±1.3 | 2.3±1.3 | <0.001 |
| Ultrafiltration (%)a | 3.4±1.5 | 3.6±1.5 | 3.6±1.4 | 3.5±1.4 | 3.4±1.5 | 3.2±1.6 | 3.1±1.6 | 3.0±1.6 | <0.001 |
| BMI (kg/m2)b | 26.9±6.1 | 27.9±6.5 | 27.5±6.3 | 27.0±6.1 | 26.6±6.0 | 26.2±5.8 | 26.3±6.1 | 26.5±6.2 | <0.001 |
| Laboratory measures (baseline) | |||||||||
| Kt/V (single pool) | 1.55±0.30 | 1.56±0.30 | 1.56±0.30 | 1.55±0.30 | 1.54±0.31 | 1.53±0.31 | 1.54±0.31 | 1.53±0.31 | <0.001 |
| Albumin (g/dl) | 3.7±0.5 | 3.7±0.4 | 3.7±0.4 | 3.7±0.4 | 3.7±0.5 | 3.6±0.5 | 3.6±0.5 | 3.6±0.5 | <0.001 |
| Creatinine (mg/dl) | 8.0±3.2 | 7.7±2.9 | 8.1±3.1 | 8.3±3.2 | 8.1±3.3 | 7.6±3.1 | 7.1±3.0 | 7.0±2.8 | <0.001 |
| TIBC (mg/dl) | 208±45 | 212±43 | 210±43 | 208±44 | 207±45 | 206±46 | 208±48 | 207±47 | <0.001 |
| Ferritin (ng/ml)c | 390 (190–683) | 373 (184–663) | 414 (198–702) | 410 (200–698) | 391 (189–687) | 377 (183–674) | 349 (173–640) | 341 (174–619) | <0.001 |
| Bicarbonate (mg/dl) | 22.1±3.2 | 22.2±3.2 | 22.0±3.1 | 21.9±3.1 | 22.1±3.1 | 22.4±3.2 | 22.6±3.1 | 22.7±3.2 | <0.001 |
| Calcium (mg/dl) | 9.5±0.7 | 9.5±0.7 | 9.6±0.7 | 9.6±0.7 | 9.5±0.7 | 9.5±0.7 | 9.5±0.7 | 9.5±0.6 | <0.001 |
| Phosphorus (mg/dl) | 5.6±1.5 | 5.7±1.4 | 5.7±1.4 | 5.7±1.5 | 5.6±1.5 | 5.5±1.5 | 5.4±1.5 | 5.4±1.5 | <0.001 |
| Hemoglobin (g/dl) | 12.1±1.3 | 12.3±1.3 | 12.3±1.2 | 12.2±1.3 | 12.1±1.3 | 12.0±1.4 | 12.0±1.4 | 12.1±1.4 | <0.001 |
| WBC (×103/µl) | 7.38±2.43 | 7.51±2.36 | 7.42±2.29 | 7.35±2.42 | 7.31±2.46 | 7.36±2.41 | 7.52±2.60 | 7.64±2.62 | 0.04 |
| Lymphocyte (%) | 20.6±7.8 | 20.7±7.4 | 21.1±7.6 | 21.0±7.8 | 20.6±8.0 | 20.1±7.8 | 19.8±7.6 | 19.6±7.7 | <0.001 |
Data are presented as percentages, means±SDs, or as otherwise indicated. The P value for trend shows the differences in each variable across ∆PP categories. HD, hemodialysis; DM, diabetes mellitus; IHD, ischemic heart disease; CHF, congestive heart failure; COPD, chronic obstructive pulmonary disease; CVD, cerebrovascular disease; PVD, peripheral vascular disease; AVF, arteriovenous fistula; AVG, arteriovenous graft; PP, pulse pressure; ∆PP, postdialysis pulse pressure minus predialysis pulse pressure; BMI, body mass index; TIBC, total iron-binding capacity; WBC, white blood cells.
a
Calculated as [(predialysis weight−postdialysis weight)/predialysis weight]×100.
b
Calculated using postdialysis weight and height.
c
Median (interquartile range) is used.