Table 1.
Baseline characteristics
| Characteristics | Water Deprivation Test Participants | DIPAK Participants |
|---|---|---|
| No. | 30 | 583 |
| Age, yr | 42±13 | 47±11 |
| Sex, % male | 57 | 42 |
| Body mass index, kg/m2 | 27±3.9 | 26±4.6 |
| Systolic BP, mm Hg | 134±12 | 131±14 |
| Diastolic BP, mm Hg | 84±8 | 81±9 |
| Antihypertensive therapy, % yes | 73 | 77 |
| Diuretics, % yes | — | 28 |
| Thiazide diuretics, % yes | — | 25 |
| Loop diuretics, % yes | — | 2 |
| PKD mutation, % | ||
| PKD1 T | 37 | 42 |
| PKD1 NT | 50 | 26 |
| PKD2 | 7 | 21 |
| Other | 7 | 9 |
| htTKV, ml/m | 578 [497–1140] | 898 [549–1364] |
| Mayo Clinic htTKV class, % | ||
| 1A | 7 | 5 |
| 1B | 23 | 20 |
| 1C | 23 | 33 |
| 1D | 17 | 22 |
| 1E | 20 | 12 |
| 2 | 10 | 3 |
| Plasma creatinine, mg/dl | 1.11 [0.87–1.65] | 1.22 [0.97–1.57] |
| eGFR, ml/min per 1.73 m2 | 74±32 | 64±24 |
| Plasma urea, mg/dl | 22 [17–29] | 21 [16–27] |
| Baseline copeptin, pmol/L | 9.0 [4.9–20] | 7.7 [4.5–13.2] |
| 24-h urine volume, L | 2.4±0.9 | 2.3±0.8 |
| Urine urea, mg/dl | 785 [573–1011] | 549 [406–692] |
| Estimated protein intake, g/24 h | 88±22 | 85±25 |
| Estimated salt intake, g/24 h | 9.1 [7.0–13.3] | 8.5 [6.3–11.1] |
| Maximal urine-concentrating capacity, mOsm/kg | 633±171 | — |
| Urine-to-plasma urea ratio | 37 [23–48] | 24 [17–36] |
Data presented as mean ± SD, median [interquartile range], or proportion of total population (%) as appropriate. Diuretic use was an exclusion criterion for participation in the water deprivation tests. Maximal urine-concentrating capacity was defined as the plateau of highest urine osmolality that was reached after a prolonged water deprivation test. Urine urea was measured in an early morning fasting void. Protein intake was estimated in grams with the following equation: (urine urea excretion in 24 h×0.4667×0.06+[0.031× weight])×6.25 (37). Salt intake was estimated with the following equation: sodium excretion in moles×(sum of molecular mass of sodium and chloride in grams per mole). DIPAK, Developing Interventions to Halt Progression of Autosomal Dominant Polycystic Kidney Disease; —, not applicable; T, truncating; NT, nontruncating; htTKV, height-adjusted total kidney volume.