Table 1.
Characteristics of Patients with SIADH and Hypovolemia
| SIADH | Hypovolemia | P-value | |
| N = 29 | N = 16 | ||
| Age | 81.0 ± 9.2 | 79.3 ± 8.1 | 0.514 |
| Gender - male sex - no. (%) | 12 (41) | 6 (37.5) | 1.0 |
| Chief complaints | |||
| Altered mental status - no. (%) | 8 (27.6) | 2 (12.5) | 0.292 |
| Fall - no. (%) | 8 (27.6) | 9 (56.3) | 0.115 |
| Bone fracture - no. (%) | 5 (17.2) | 2 (12.5) | 1.0 |
| Acute pain - no. (%) | 14 (48.3) | 5 (31.3) | 0.429 |
| Intracranial event - no. (%) | 2 (6.9) | 0 (0) | 0.531 |
| Vomiting - no. (%) | 5 (17.2) | 3 (18.8) | 1.0 |
| Underlying condition | |||
| Pulmonary disease (non malignant) - no. (%) | 10 (34.5) | 1 (6.2) | 0.067 |
| Neoplasm - no. (%) | 6 (20.7) | 2 (12.5) | 0.692 |
| Use of antipsychotics antidepressants - no. (%) | 8 (27.6) | 2 (12.5) | 0.292 |
| Diuretic use - no. (%) | 5 (17.2) | 10 (62.5) | 0.006 |
| Hydrochlorothiazide | 4 | 6 | |
| Furosemide | 2 | 4 | |
| Spironolactone | 0 | 3 | |
| Biochemical data | |||
| Serum creatinine - mg/dL | 0.78 ± 0.23 | 1.06 ± 0.28 | 0.001 |
| Estimated GFR (MDRDb) - ml/min | 94.1 ± 31.4 | 66.8 ± 25.0 | 0.003 |
| BUN - mg/dL | 13.2 ± 6.3 | 24.1 ± 12.3 | 0.003 |
| 0.061a | |||
| Serum Na (0h) - mEq/L | 120.8 ± 5.3 | 123.3 ± 5.7 | 0.153 |
| Serum Na (24h) - mEq/L | 123.8 ± 5.7 | 131.2 ± 3.6 | <0.001 |
| Serum Na (48h) - mEq/L | 126.9 ± 4.5 | 135.0 ± 2.1 | <0.001 |
| Initial Urine Na - mEq/L | 85.1 ± 31.4 | 40.3 ± 23.0 | <0.001 0.002a |
| Urine Na/BUN ratio | 8.6 ± 6.7 | 2.0 ± 1.3 | <0.001 0.009a |
| Urine osmolarity - mOsm/kg | 424.8 ± 158.4 | 307.1 ± 192.6 | 0.053 |
Note: Plus-minus values are means ± SD
a
Logistic regression model, adjusted for glomerular filtration rate and diuretic use
b
Glomerular Filtration Rate, Four-variable Modification of Diet in Renal Disease (MDRD)
Conversion factors for units: BUN in mg/dL to mmol/L, x0.357; serum creatinine in mg/dL to mol/L, x88.4