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| ID | Type | Description | Link |
|---|---|---|---|
| 13CRP16970085 | Other Grant/Funding Number | American Heart Association | |
| Satellite Dialysis | Other Grant/Funding Number | National Kidney Foundation |
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| Name | Class |
|---|---|
| Johns Hopkins University | OTHER |
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Phosphorus-based food additives are commonly used by food manufacturers for many applications, such as enhancing flavor, in ready-to-eat foods and beverages. While these additives can significantly increase an individual's daily phosphorus intake, little is known about the effect of dietary phosphorus on kidney health. In this study, the investigators will first lower baseline phosphorus intake to about 1000mg/d by educating participants to avoid foods with phosphorus additives. Then, participants will be randomized to a higher phosphorus period (~2gm/d) and a lower phosphorus period (~1gm/d) by providing unaltered, commercially-available food/beverage products with and without phosphorus additives.
The investigators hypothesize that participants will have higher urine albumin excretion and fibroblast growth factor-23 (FGF-23) during the higher phosphorus period compared to the lower phosphorus period.
The Study of Dietary Additive Phosphorus on Proteinuria and FGF-23 (SODA-POP) was a single-center, randomized, double-blind, two-period cross-over study that examined the effect of higher vs. lower phosphorus intake for 3 week periods, achieved by addition of commercially available diet beverages and breakfast bars to diet on albuminuria and fibroblast growth factor 23, in adults with presumed early chronic kidney disease (estimated glomerular filtration rate >= 45 ml/min/1.73m2; and urine albumin/creatinine ratio >=17 mg/g for men or >=25 mg/g for women).
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Higher phosphorus period | Active Comparator | Commercially-available unaltered food/beverage products containing phosphorus additives (~1gm/d of phosphorus) will be given for 3 weeks |
|
| Lower phosphorus period | Placebo Comparator | Commercially-available unaltered food/beverage products without phosphorus additives (<10mg/d of phosphorus) will be given for 3 weeks |
|
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Higher phosphorus period | Other | Commercially-available unaltered food/beverage products containing phosphorus additives (~1gm/d of phosphorus) will be given for 3 weeks. All participants at the beginning of the study will receive dietary education to reduce their baseline consumption of phosphorus to a goal of ~1gm/d by receiving education on avoiding phosphorus-based additives. |
| Measure | Description | Time Frame |
|---|---|---|
| 24-hour Urine Albumin Excretion | Two 24-hour urine collections will be collected during the 3rd week of each period | 3 weeks |
| Fibroblast Growth Factor-23 (FGF-23) | Plasma FGF-23 will be measured at the end of each 3 week period in the morning after an overnight fast. As this is a small pilot study, we will not adjust for multiple comparisons. A p value<0.05 will be considered statistically significant for both outcomes | 3 weeks |
| Measure | Description | Time Frame |
|---|---|---|
| Systolic Blood Pressure | Blood pressure was measured at the end of weeks 1, 2, and 3. At each visit, 3 readings were obtained in the seated position by trained and certified observers after 5 minutes of rest with an Omron HEM-907 device (Omron Healthcare Inc, Bannockburn, Ill) using a standardized protocol. We used the average of all blood pressure measurements at the end of weeks 1, 2, and 3 for each period. |
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Inclusion Criteria:
Adults at least 21 years of age with at least microalbuminuria
Exclusion Criteria:
Estimated glomerular filtration rate <45ml/min/1.73m2, poorly controlled diabetes or hypertension, nephrotic syndrome, hyperparathyroidism, Paget's Disease, multiple myeloma, uncontrolled thyroid disease, chronic antacid use, use of phosphorus binders, phosphorus supplements, or high-dose vitamin D, inability to complete feeding study, investigator discretion
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| Name | Affiliation | Role |
|---|---|---|
| Alex R Chang, MD, MS | Geisinger Clinic | Principal Investigator |
| Lawrence J Appel, MD, MPH | Johns Hopkins University | Study Director |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Prohealth Clinical Research Unit | Baltimore | Maryland | 21207 | United States |
| PubMed Identifier | Type | Citation | Retractions |
|---|---|---|---|
| 23810691 | Background | Chang A, Batch BC, McGuire HL, Vollmer WM, Svetkey LP, Tyson CC, Sanguankeo A, Anderson C, Houston J, Appel LJ. Association of a reduction in central obesity and phosphorus intake with changes in urinary albumin excretion: the PREMIER study. Am J Kidney Dis. 2013 Nov;62(5):900-7. doi: 10.1053/j.ajkd.2013.04.022. Epub 2013 Jun 28. |
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Primary recruitment strategies included mass mailing of study brochures to individuals with self-reported type 2 diabetes in neighboring zip codes and to past and current participants of other research studies.
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| ID | Title | Description |
|---|---|---|
| FG000 | Higher Phosphorus Period First, Then Lower Phosphorus Period | Randomized to higher phosphorus period first, then lower phosphorus period second. Commercially-available unaltered food/beverage products containing phosphorus additives (~1gm/d of phosphorus) will be given for 3 weeks At the beginning of the study participants receive dietary education to reduce their baseline consumption of phosphorus to a goal of ~1gm/d by receiving education on avoiding phosphorus-based additives Higher phosphorus period: Commercially-available unaltered food/beverage products containing phosphorus additives (~1gm/d of phosphorus) given for 3 weeks Lower phosphorus period: Commercially-available unaltered food/beverage products without any phosphorus additives given for 3 weeks |
| FG001 | Lower Phosphorus Period First, Then Higher Phosphorus Period | Randomized to higher phosphorus period first, then lower phosphorus period second. Commercially-available unaltered food/beverage products containing phosphorus additives (~1gm/d of phosphorus) will be given for 3 weeks At the beginning of the study participants receive dietary education to reduce their baseline consumption of phosphorus to a goal of ~1gm/d by receiving education on avoiding phosphorus-based additives Lower phosphorus period: Commercially-available unaltered food/beverage products without any phosphorus additives given for 3 weeks Higher phosphorus period: Commercially-available unaltered food/beverage products containing phosphorus additives (~1gm/d of phosphorus) given for 3 weeks |
| Title | Milestones | Reasons Not Completed | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| First Intervention (3 Weeks) |
| |||||||||||||
| Second Intervention (3 Weeks) |
|
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| ID | Title | Description |
|---|---|---|
| BG000 | Higher Phosphorus Period Then Lower Phosphorus Period | Randomized to higher phosphorus period first, then lower phosphorus period second. Commercially-available unaltered food/beverage products containing phosphorus additives (~1gm/d of phosphorus) will be given for 3 weeks At the beginning of the study participants receive dietary education to reduce their baseline consumption of phosphorus to a goal of ~1gm/d by receiving education on avoiding phosphorus-based additives Higher phosphorus period: Commercially-available unaltered food/beverage products containing phosphorus additives (~1gm/d of phosphorus) given for 3 weeks Lower phosphorus period: Commercially-available unaltered food/beverage products without any phosphorus additives given for 3 weeks |
| Units | Counts |
|---|---|
| Participants |
|
| Title | Description | Population Description | Parameter Type | Dispersion Type | Unit of Measure | Calculate Percentage | Denominator Units Selected | Denominators | Classes |
|---|---|---|---|---|---|---|---|---|---|
| Age, Categorical | Count of Participants |
| Type | Title | Description | Population Description | Reporting Status | Anticipated Posting Date | Parameter Type | Dispersion Type | Unit of Measure | Calculate Percentage | Time Frame | Units Analyzed | Denominator Units Selected | Arm/Group Information | Denominators | Classes | Analyses | |||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Primary | 24-hour Urine Albumin Excretion | Two 24-hour urine collections will be collected during the 3rd week of each period | Posted | Mean | 95% Confidence Interval | mg/day | 3 weeks |
|
At the end of each 3 week study period.
Participants were asked at the end of each study period if they experienced possible side effects.
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| ID | Title | Description | Deaths (Affected) | Deaths (At Risk) | Serious Events (Affected) | Serious Events (At Risk) | Other Events (Affected) | Other Events (At Risk) |
|---|---|---|---|---|---|---|---|---|
| EG000 | Higher Phosphorus Period | Commercially-available unaltered food/beverage products containing phosphorus additives (~1gm/d of phosphorus) given for 3 weeks |
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| Term | Organ System | Source Vocabulary | Assessment Type | Notes | Statistical Information |
|---|---|---|---|---|---|
| Gastrointestinal symptoms | Gastrointestinal disorders | Systematic Assessment | Participants were asked at the end of each study period if they experienced possible side effects. The specific adverse event terms cannot be separated due to the manner in which this was assessed. |
Small sample size, short duration of intervention, changes in background diet during the intervention.
| Title | Organization | Phone | Extension | |
|---|---|---|---|---|
| Alex Chang, MD | Geisinger | 570-271-8026 | achang@geisinger.edu |
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| ID | Term |
|---|---|
| D000419 | Albuminuria |
| D011507 | Proteinuria |
| ID | Term |
|---|---|
| D014555 | Urination Disorders |
| D014570 | Urologic Diseases |
| D052776 | Female Urogenital Diseases |
| D005261 | Female Urogenital Diseases and Pregnancy Complications |
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|
| Lower phosphorus period | Other | Commercially-available unaltered food/beverage products without phosphorus additives (<10mg/d of phosphorus) will be given for 3 weeks. All participants at the beginning of the study will receive dietary education to reduce their baseline consumption of phosphorus to a goal of ~1gm/d by receiving education on avoiding phosphorus-based additives. |
|
| 2-3 weeks |
| Diastolic Blood Pressure | Blood pressure measured at the end of weeks 1, 2, and 3. At each visit, 3 readings were obtained in the seated position by trained and certified observers after 5 minutes of rest with an Omron HEM-907 device (Omron Healthcare Inc, Bannockburn, Ill) using a standardized protocol. We used the average of all these readings taken during end of weeks 1, 2, and 3 for each period. | 2-3 weeks |
| NOT COMPLETED |
|
| BG001 | Lower Phosphorus Period Then Higher Phosphorus Period | Randomized to higher phosphorus period first, then lower phosphorus period second. Commercially-available unaltered food/beverage products containing phosphorus additives (~1gm/d of phosphorus) will be given for 3 weeks At the beginning of the study participants receive dietary education to reduce their baseline consumption of phosphorus to a goal of ~1gm/d by receiving education on avoiding phosphorus-based additives Lower phosphorus period: Commercially-available unaltered food/beverage products without any phosphorus additives given for 3 weeks Higher phosphorus period: Commercially-available unaltered food/beverage products containing phosphorus additives (~1gm/d of phosphorus) given for 3 weeks |
| BG002 | Total | Total of all reporting groups |
| Participants |
|
| Age, Continuous | Mean | Standard Deviation | years |
|
| Sex: Female, Male | Count of Participants | Participants |
|
| Ethnicity (NIH/OMB) | Count of Participants | Participants |
|
| Race (NIH/OMB) | Count of Participants | Participants |
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| Region of Enrollment | Number | participants |
|
| OG001 | Lower Phosphorus Period | Commercially-available unaltered food/beverage products containing phosphorus additives (~1gm/d of phosphorus) will be given for 3 weeks At the beginning of the study participants receive dietary education to reduce their baseline consumption of phosphorus to a goal of ~1gm/d by receiving education on avoiding phosphorus-based additives. Patients then randomized to higher phosphorus period or lower phosphorus period first. Higher phosphorus period: Commercially-available unaltered food/beverage products containing phosphorus additives (~1gm/d of phosphorus) given for 3 weeks Lower phosphorus period: Commercially-available unaltered food/beverage products without any phosphorus additives given for 3 weeks |
|
|
|
| Primary | Fibroblast Growth Factor-23 (FGF-23) | Plasma FGF-23 will be measured at the end of each 3 week period in the morning after an overnight fast. As this is a small pilot study, we will not adjust for multiple comparisons. A p value<0.05 will be considered statistically significant for both outcomes | Posted | Geometric Mean | 95% Confidence Interval | Relative units/ml | 3 weeks |
|
|
|
|
| Secondary | Systolic Blood Pressure | Blood pressure was measured at the end of weeks 1, 2, and 3. At each visit, 3 readings were obtained in the seated position by trained and certified observers after 5 minutes of rest with an Omron HEM-907 device (Omron Healthcare Inc, Bannockburn, Ill) using a standardized protocol. We used the average of all blood pressure measurements at the end of weeks 1, 2, and 3 for each period. | Posted | Mean | Standard Deviation | mmHg | 2-3 weeks |
|
|
|
|
| Secondary | Diastolic Blood Pressure | Blood pressure measured at the end of weeks 1, 2, and 3. At each visit, 3 readings were obtained in the seated position by trained and certified observers after 5 minutes of rest with an Omron HEM-907 device (Omron Healthcare Inc, Bannockburn, Ill) using a standardized protocol. We used the average of all these readings taken during end of weeks 1, 2, and 3 for each period. | Posted | Mean | Standard Deviation | mmHg | 2-3 weeks |
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|
|
|
| 0 |
| 31 |
| 0 |
| 31 |
| 22 |
| 31 |
| EG001 | Lower Phosphorus Period | Commercially-available unaltered food/beverage products without phosphorus additives (<10mg/d of phosphorus) given for 3 weeks | 0 | 31 | 0 | 31 | 23 | 31 |
|
| Back pain | Musculoskeletal and connective tissue disorders | Systematic Assessment |
|
| Flu-like symptoms | Infections and infestations | Systematic Assessment |
|
| Fatigue | General disorders | Systematic Assessment |
|
| Skin rash | Skin and subcutaneous tissue disorders | Systematic Assessment |
|
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| D000091642 | Urogenital Diseases |
| D052801 | Male Urogenital Diseases |
| D020924 | Urological Manifestations |
| D012816 | Signs and Symptoms |
| D013568 | Pathological Conditions, Signs and Symptoms |