Table 1.
Baseline demographic data and pretreatment laboratory values (SD) with adjusted differences by race (95% confidence interval)
| Black | White | Adjusted Difference Black versus Whitea | P Value | |
|---|---|---|---|---|
| N | 117 | 172 | ||
| Sex, men/women | 39/78 | 84/88 | ||
| Age, yr | 51 (14) | 47 (15) | ||
| Weight, kg | 87 (22) | 79 (23) | ||
| Stone analysis (% of available stone analyses) | 62 | 96 | ||
| Calcium oxalate | 45 (73) | 66 (69) | ||
| Calcium phosphate | 9 (15) | 17 (18) | ||
| Uric acid | 8 (13) | 12 (12) | ||
| Serum values | ||||
| Sodium, mmol/L | 140.4 (2.0) | 139.5 (1.5) | 0.9 (0.5 to 1.3) | <0.001 |
| Potassium, mmol/L | 4.2 (0.5) | 4.3 (0.3) | −0.07 (−0.15 to 0.01) | 0.07 |
| Bicarbonate, mmol/L | 26.4 (2.2) | 26.6 (0.2) | −0.1 (−0.6 to 0.5) | 0.77 |
| Calcium, mg/dl | 9.5 (0.5) | 9.6 (0.3) | −0.1 (−0.18 to −0.03) | 0.005 |
| Phosphate, mg/dl | 3.3 (0.6) | 3.5 (0.04) | −0.2 (−0.3 to −0.1) | <0.001 |
| Creatinine, mg/dl | 1.1 (0.3) | 0.9 (0.3) | 0.2 (0.1 to 0.3) | 0.001 |
| 24-h urine values | ||||
| Volume, L/d | 1.4 (0.8) | 2.0 (0.8) | −0.6 (−0.8 to −0.4) | <0.001 |
| pH | 5.9 (0.5) | 6.0 (0.5) | −0.1 (−0.2 to 0.0) | 0.15 |
| Creatinine, mg/d | 1432 (500) | 1395 (439) | 42 (−24 to 109) | 0.23 |
| Sodium, mmol/d | 135 (55) | 160 (62) | −30 (−41 to −19) | <0.001 |
| Potassium, mmol/d | 42 (18) | 58 (21) | −16 (−20 to −12) | <0.001 |
| Calcium, mg/d | 116 (70) | 217 (115) | −110 (−131 to −88) | <0.001 |
| Magnesium, mg/d | 76 (39) | 104 (41) | −29 (−37 to −21) | <0.001 |
| Sulfate, meq/d | 34 (14) | 44 (19) | −12 (−15 to −9) | <0.001 |
| Ammonium, meq/d | 28 (13) | 32 (13) | −1 (−4 to 2)b | 0.54 |
| Phosphate, mg/d | 645 (239) | 939 (321) | −314 (−360 to −268) | <0.001 |
| Oxalate, mg/d | 37 (14) | 39 (16) | −2.5 (−6 to 1) | 0.15 |
| Citrate, mg/d | 446 (282) | 556 (310) | −133 (−200 to −66) | <0.001 |
| Uric acid, mg/d | 503 (177) | 612 (214) | −135 (−163 to −106) | <0.001 |
| Urea nitrogen, g/d | 8.4 (3.1) | 10.5 (4.2) | −2.0 (−3.2 to −0.9) | 0.001 |
| Sodium + potassium, meq/d | 177 (65) | 218 (75) | −46 (−59 to −33) | <0.001 |
| Clearance H2O, ml/d | 207 (780) | 435 (759) | −222 (−400 to −42) | 0.02 |
| Creatinine clearance, ml/min | 96 (33) | 106 (32) | −12 (−19 to −5) | 0.001 |
| Supersaturation calcium oxalate | 7.6 (4.8) | 7.1 (3.3) | 0.6 (−0.3 to 1.6) | 0.20 |
| Supersaturation calcium phosphate | 0.8 (0.7) | 1.2 (0.9) | −0.4 (−0.6 to −0.2) | <0.001 |
| Supersaturation uric acid | 1.2 (0.9) | 0.9 (0.8) | 0.3 (0.1 to 0.5) | 0.003 |
a
All values are adjusted for sex. Serum creatinine and all urine values except supersaturation are adjusted for weight. All urine values are adjusted for 24-hour urine creatinine (except pH, supersaturation, and creatinine clearance).
b
Adjusted for urine sulfate. All P values are Bonferroni adjusted.