Calcium Phosphate Kidney Stones
Conditions
Keywords
calcium phosphate, urolithiasis, kidney stones, hypercalciuria
Brief summary
The investigators will examine in two studies whether citric acid or potassium citrate can reduce calcium phosphate saturation in urine of Calcium Phosphate stone formers.
Detailed description
We will examine in two short-term placebo-controlled cross-over metabolic studies whether citric acid or potassium citrate can reduce calcium phosphate saturation in urine of CaP stone formers. The first study will be conducted in hypocitraturic CaP stone formers without hypercalciuria, and will compare the effects of potassium citrate, citric acid and placebo. The second study will be conducted in hypercalciuric CaP stone formers on a thiazide diuretic who require potassium supplementation, and will compare the effects of potassium chloride alone, potassium chloride + citric acid, and potassium citrate alone. Physicochemical assays will be applied in addition to computer-based stone risk prediction programs to assess risk of stone recurrence.
Interventions
DIETARY_SUPPLEMENTPlacebo
3 tablets twice daily of matching placebo during the placebo phase.
DIETARY_SUPPLEMENTCitric Acid
3, 10 mEq tablets of H3Cit twice daily during the H3Cit phase (60 mEq H3Cit per day)
DIETARY_SUPPLEMENTPotassium Citrate
2, 10 mEq K3Cit tablets and 1 placebo tablet twice daily during the K3Cit phase (40 mEq K3Cit per day)
Sponsors
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
University of Texas Southwestern Medical Center
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
TREATMENT
Masking
DOUBLE (Subject, Investigator)
Eligibility
Sex/Gender
ALL
Age
21 Years to No maximum
Healthy volunteers
No
Inclusion criteria
Aim 1 * Hypocitraturic CaP stone formers * urine citrate \<320mg/d * elevated pH as 24-hr urine pH above 6.40 * \>21 years Aim 2 * Hypercalciuric CaP stone formers * 24hr urine calcium \>250mg/d in women and \>300mg/d in men prior to indapamide use * high pH as \>6.40 in the absence of urinary tract infection * \>21 years
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Urinary Calcium Phosphate Saturation | 2 weeks | This variable represents a ratio of the calcium phosphate saturation in a given urine sample to the calcium phosphate saturation at the point of precipitation and hence this measure has no units. |
Countries
United States
Participant flow
Pre-assignment details
Out of 41 patients who met inclusion criteria and were contacted for study enrollment, a total of 13 subjects agreed to enroll and were consented and each participant was evaluated during 3 phases in randomized order.
Participants by arm
| Arm | Count |
|---|---|
| Placebo, Then Citric Acid, Then Potassium Citrate Placebo: 3 tablets twice daily of matching placebo during the placebo phase.
Citric Acid: 3, 10 mEq tablets of H3Cit twice daily during the H3Cit phase (60 mEq H3Cit per day)
Potassium Citrate: 2, 10 mEq K3Cit tablets and 1 placebo tablet twice daily during the K3Cit phase (40 mEq K3Cit per day) | 2 |
| Placebo, Then Potassium Citrate, Then Citric Acid Placebo: 3 tablets twice daily of matching placebo during the placebo phase.
Potassium Citrate: 2, 10 mEq K3Cit tablets and 1 placebo tablet twice daily during the K3Cit phase (40 mEq K3Cit per day)
Citric Acid: 3, 10 mEq tablets of H3Cit twice daily during the H3Cit phase (60 mEq H3Cit per day) | 1 |
| Potassium Citrate, Then Placebo, Then Citric Acid Potassium Citrate: 2, 10 mEq K3Cit tablets and 1 placebo tablet twice daily during the K3Cit phase (40 mEq K3Cit per day)
Placebo: 3 tablets twice daily of matching placebo during the placebo phase.
Citric Acid: 3, 10 mEq tablets of H3Cit twice daily during the H3Cit phase (60 mEq H3Cit per day) | 2 |
| Potassium Citrate, Then Citric Acid, Then Placebo Potassium Citrate: 2, 10 mEq K3Cit tablets and 1 placebo tablet twice daily during the K3Cit phase (40 mEq K3Cit per day)
Citric Acid: 3, 10 mEq tablets of H3Cit twice daily during the H3Cit phase (60 mEq H3Cit per day)
Placebo: 3 tablets twice daily of matching placebo during the placebo phase. | 3 |
| Citric Acid, Then Potassium Citrate, Then Placebo Citric Acid: 3, 10 mEq tablets of H3Cit twice daily during the H3Cit phase (60 mEq H3Cit per day)
Potassium Citrate: 2, 10 mEq K3Cit tablets and 1 placebo tablet twice daily during the K3Cit phase (40 mEq K3Cit per day)
Placebo: 3 tablets twice daily of matching placebo during the placebo phase. | 3 |
| Citric Acid, Then Placebo, Then Potassium Citrate Citric Acid: 3, 10 mEq tablets of H3Cit twice daily during the H3Cit phase (60 mEq H3Cit per day)
Placebo: 3 tablets twice daily of matching placebo during the placebo phase.
Potassium Citrate: 2, 10 mEq K3Cit tablets and 1 placebo tablet twice daily during the K3Cit phase (40 mEq K3Cit per day) | 2 |
| Total | 13 |
Baseline characteristics
| Characteristic | Placebo, Then Citric Acid, Then Potassium Citrate | Placebo, Then Potassium Citrate, Then Citric Acid | Potassium Citrate, Then Placebo, Then Citric Acid | Potassium Citrate, Then Citric Acid, Then Placebo | Citric Acid, Then Potassium Citrate, Then Placebo | Citric Acid, Then Placebo, Then Potassium Citrate | Total |
|---|---|---|---|---|---|---|---|
| Age, Continuous | 35.9 years STANDARD_DEVIATION 9.2 | 34.8 years | 49.2 years STANDARD_DEVIATION 27.9 | 41.4 years STANDARD_DEVIATION 24.5 | 45.6 years STANDARD_DEVIATION 11.8 | 35.6 years STANDARD_DEVIATION 1.3 | 41 years STANDARD_DEVIATION 15 |
| Body mass index (BMI) | 26.9 kg/m^2 STANDARD_DEVIATION 2.8 | 35.9 kg/m^2 | 28.9 kg/m^2 STANDARD_DEVIATION 8 | 21.2 kg/m^2 STANDARD_DEVIATION 2.7 | 32.1 kg/m^2 STANDARD_DEVIATION 2.1 | 20.2 kg/m^2 STANDARD_DEVIATION 4 | 26.7 kg/m^2 STANDARD_DEVIATION 6.4 |
| Height | 1.66 metres STANDARD_DEVIATION 0.13 | 1.58 metres | 1.56 metres STANDARD_DEVIATION 0.02 | 1.63 metres STANDARD_DEVIATION 0.18 | 1.69 metres STANDARD_DEVIATION 0.06 | 1.64 metres STANDARD_DEVIATION 0.05 | 1.63 metres STANDARD_DEVIATION 0.1 |
| Race/Ethnicity, Customized Black | 0 participants | 0 participants | 0 participants | 0 participants | 2 participants | 0 participants | 2 participants |
| Race/Ethnicity, Customized Hispanic | 1 participants | 1 participants | 1 participants | 1 participants | 0 participants | 0 participants | 4 participants |
| Race/Ethnicity, Customized Non-Hispanic | 0 participants | 0 participants | 1 participants | 2 participants | 3 participants | 2 participants | 8 participants |
| Race/Ethnicity, Customized White | 2 participants | 1 participants | 2 participants | 3 participants | 1 participants | 2 participants | 11 participants |
| Sex: Female, Male Female | 1 Participants | 1 Participants | 2 Participants | 2 Participants | 3 Participants | 2 Participants | 11 Participants |
| Sex: Female, Male Male | 1 Participants | 0 Participants | 0 Participants | 1 Participants | 0 Participants | 0 Participants | 2 Participants |
| Weight | 74.2 kg STANDARD_DEVIATION 3.4 | 89.0 kg | 70.3 kg STANDARD_DEVIATION 18 | 56.7 kg STANDARD_DEVIATION 16 | 91.4 kg STANDARD_DEVIATION 11 | 53.8 kg STANDARD_DEVIATION 7.4 | 71.6 kg STANDARD_DEVIATION 18.5 |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk | EG002 affected / at risk |
|---|---|---|---|
| deaths Total, all-cause mortality | 0 / 13 | 0 / 13 | 0 / 13 |
| other Total, other adverse events | 0 / 13 | 0 / 13 | 0 / 13 |
| serious Total, serious adverse events | 0 / 13 | 0 / 13 | 0 / 13 |
Outcome results
Primary
Urinary Calcium Phosphate Saturation
This variable represents a ratio of the calcium phosphate saturation in a given urine sample to the calcium phosphate saturation at the point of precipitation and hence this measure has no units.
Time frame: 2 weeks
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Placebo | Urinary Calcium Phosphate Saturation | 2.38 no units | Standard Deviation 1.07 |
| Citric Acid | Urinary Calcium Phosphate Saturation | 1.97 no units | Standard Deviation 0.75 |
| Potassium Citrate | Urinary Calcium Phosphate Saturation | 2.19 no units | Standard Deviation 0.96 |