Study of Dietary Additive Phosphorus on Proteinuria and Fibroblast Growth Factor-23

Albuminuria Clinical Trial

— SODA-POP  

Official title:

Randomized Cross-over Study Examining the Effects of Phosphorus Additives on Urinary Albumin Excretion and Fibroblast Growth Factor-23

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT02020785
• Other study ID #: NA_00082089
• Secondary ID: 13CRP16970085Sat
• Status: Completed
• Phase: N/A
• Start date: January 2014
• Est. completion date: September 2015

Study information

• Verified date: February 2019
• Source: Geisinger Clinic
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

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.

Description:

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).

Recruitment information / eligibility

• Status: Completed
• Enrollment: 31
• Est. completion date: September 2015
• Est. primary completion date: September 2015
• Accepts healthy volunteers: No
• Gender: All
• Age group: 21 Years and older

Eligibility

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

Related Conditions & MeSH terms

• Albuminuria
• Proteinuria

Intervention

Other:
• Higher phosphorus period
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.
• Lower phosphorus period
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.

Locations

Country	Name	City	State
United States	Prohealth Clinical Research Unit	Baltimore	Maryland

Sponsors (2)

Lead Sponsor	Collaborator
Geisinger Clinic	Johns Hopkins University

Country where clinical trial is conducted

United States, 

References & Publications (1)

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. — View Citation

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	24-hour Urine Albumin Excretion	Two 24-hour urine collections will be collected during the 3rd week of each period	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	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.	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.	2-3 weeks