Table 1.
Characteristics of the study population.
| Total | Low turnover | Normal turnover | High turnover | P | |
|---|---|---|---|---|---|
| N | 141 | 52 | 21 | 68 | |
| Age (years) | 49.9 ± 15.1 | 53.3 ± 17.0 | 47.6 ± 12.7 | 48.0 ± 13.9 | 0.1 |
| Dialysis Duration (months) | 36.5 ± 35.3 | 34.0 ± 31.0 | 22.4 ± 17.3 | 39.3 ± 40.9 | 0.2 |
| Gender | 0.8 | ||||
| Female (%) | 69 (48.9) | 24 (34.8) | 10 (14.5) | 35 (50.7) | |
| Male (%) | 72 (51.1) | 28 (38.9) | 11 (15.3) | 33 (45.8) | |
| Race | 0.01 | ||||
| White (%) | 70 (49.6) | 34 (50.0) | 6 (8.6) | 29 (41.4) | |
| Black (%) | 71 (50.4) | 17 (24.0) | 15 (21.1) | 39 (54.9) | |
| Diabetes | 0.5 | ||||
| Yes (%) | 38 (27.0) | 17 (44.7) | 5 (13.2) | 16 (42.1) | |
| No (%) | 103 (73.0) | 35 (34.0) | 16 (15.5) | 52 (50.5) | |
| Vitamin D | 0.03 | ||||
| Yes (%) | 52 (36.9) | 13 (25.0) | 12 (23.1) | 27 (51.9) | |
| No (%) | 89 (63.1) | 39 (43.8) | 9 (10.1) | 41 (46.1) | |
| Phosphate Binder | 0.02 | ||||
| None (%) | 15 (10.6) | 9 (60.0) | 2 (13.3) | 4 (26.7) | |
| Calcium based (%) | 73 (51.8) | 32 (43.8) | 10 (13.7) | 31 (42.5) | |
| Non calcium based (%) | 53 (37.6) | 11 (20.8) | 9 (17.0) | 33 (62.2) | |
| Total PTH (pg/ml) | 525.3 ± 500.0 | 260.2 ± 342.6 | 494.1 ± 452.2 | 737.6 ± 520.9 | <0.001 |
| PTH 1–84 (pg/ml) | 286.0 ± 318.4 | 101.0 ± 104.9 | 287.7 ± 260.2 | 426.9 ± 369.5 | <0.001 |
| PTH ratio | 1.5 ± 1.8 | 0.8 ± 0.5 | 2.2 ± 3.1 | 1.7 ± 1.8 | 0.01 |
| Calcium level (mg/dl) | 9.1 ± 0.9 | 9.2 ± 1.0 | 8.7 ± 0.8 | 9.2 ± 0.9 | 0.06 |
| Phosphorus (mg/dl) | 6.1 ± 1.9 | 5.7 ± 1.9 | 6.4 ± 2.2 | 6.3 ± 1.8 | 0.1 |
| Activation frequency (year−1) | 0.81 ± 0.66 | 0.18 ± 0.12 | 0.60 ± 0.07 | 1.32 ± 0.56 | <0.001 |
| BFR/BS (mm3/cm2/yr) | 4.2 ± 3.2 | 1.0 ± 0.8 | 3.4 ± 0.5 | 6.7 ± 2.7 | <0.001 |
Continuous variables are summarized as mean ± standard deviation; categorical variables are summarized as count (percent). Differences in patient characteristics between the bone turnover groups were evaluated using ANOVA tests for continuous variables and chi-square or Fisher’s exact test for frequency counts.
Abbreviations and definitions: PTH = parathyroid hormone; PTH 1–84 = full-length PTH measured by a third-generation assay; PTH ratio = ratio of level of PTH 1–84 to level of large carboxy-terminal PTH fragments, BFR/BS = ratio of bone formation rate to bone surface.
Note: Conversion factors for units: serum calcium in mg/dl to mmol/L, × 0.2495; serum phosphorus in mg/dl to mmol/L, × 0.3229; no conversion necessary for PTH in pg/ml and ng/L.