CKD: Dietary Intake and Electrolyte Status (2018)

Author and Year:
Robinson-Cohen et al 2014
PubMed ID:
Article Title:
Estimation of 24-hour urine phosphate excretion from spot urine collection: development of a predictive equation.
Authors:
Robinson-Cohen C, Ix J,Smits G, Persky M, Chertow G, Block G, Kestenbaum B
Journal:
Journal of Renal Nutrition : the official journal of the Council on Renal Nutrition of the National Kidney Foundation
Year of publication:
2014
Volume:
24
Issue:
3
Page numbers:
194-9
Study Design:
Randomized Controlled Trial
Risk of Bias Assessment Rating:
Neutral
Inclusion Criteria:
133 of 148 participants in the Phosphate Normalization Trial (PNT), a 9-month randomized trial of 3 phosphate binders (sevelamer, calcium acetate or lanthanum) versus placebo among persons with moderate-to-severe (nondialysis-requiring) chronic kidney disease, with an estimate glomerular filtration rate (GFR) between 20-45 mL/min/1.73m2, serum phosphate concentration greater than 3.5-6.0 mg/dL or less, and willingness to avoid any intentional change in diet. Equations were validated using a unique random sample of 70 patients with nondialysis-requiring chronic kidney disease (CKD) from an unrelated observational study of salivary phosphate levels within PNT study center clinics.
Exclusion Criteria:
Exclusion criteria included the use of a phosphate binder other than sevelamer, calcium acetate, or lanthanum; use of activated vitamin D sterols or cinacalcet; an intact parathyroid hormone concentration of 500 pg/mL or greater; or uncontrolled hyperlipidemia. For the purpose of this analysis, study visits for which 24-hour urine collections were inadequate were also excluded (24-hour urine creatinine <600 mg for women or <800 mg for men).
Research Purpose:
To investigate the precision and accuracy of spot urine phosphate measurements, compared to 24-hour urine phosphate (24hUrP) collection, and to develop and validate a novel equation to predict 24hUrP excretion from a spot urinary specimen using data from multiple simultaneous assessments that were performed in a clinical trial of chronic kidney disease (CKD).
Blinding efforts:
Not reported.
Study Location:
United States
Source(s) of Funding:
Not reported
Please specify names of funders:
Not reported
Quality Criteria Checklist: Primary Research
Relevance Questions
  1. Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies) Yes
  2. Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about? Yes
  3. Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice? Yes
  4. Is the intervention or procedure feasible? (NA for some epidemiological studies) Yes
 
Validity Questions
1. Was the research question clearly stated? Yes
  1.1. Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified? Yes
  1.2. Was (were) the outcome(s) [dependent variable(s)] clearly indicated? Yes
  1.3. Were the target population and setting specified? Yes
2. Was the selection of study subjects/patients free from bias? ???
  2.1. Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study? Yes
  2.2. Were criteria applied equally to all study groups? Yes
  2.3. Were health, demographics, and other characteristics of subjects described? Yes
  2.4. Were the subjects/patients a representative sample of the relevant population? ???
3. Were study groups comparable? No
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) Yes
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? No
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) ???
4. Was method of handling withdrawals described? Yes
  4.1. Were follow-up methods described and the same for all groups? Yes
  4.2. Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.) Yes
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? Yes
  4.4. Were reasons for withdrawals similar across groups? N/A
5. Was blinding used to prevent introduction of bias? Yes
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? ???
  5.2. Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.) Yes
6. Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described? Yes
  6.1. In RCT or other intervention trial, were protocols described for all regimens studied? Yes
  6.3. Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? Yes
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? N/A
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? N/A
  6.6. Were extra or unplanned treatments described? N/A
  6.7. Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? Yes
7. Were outcomes clearly defined and the measurements valid and reliable? Yes
  7.1. Were primary and secondary endpoints described and relevant to the question? Yes
  7.2. Were nutrition measures appropriate to question and outcomes of concern? Yes
  7.3. Was the period of follow-up long enough for important outcome(s) to occur? Yes
  7.4. Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? Yes
  7.5. Was the measurement of effect at an appropriate level of precision? Yes
  7.6. Were other factors accounted for (measured) that could affect outcomes? ???
  7.7. Were the measurements conducted consistently across groups? Yes
8. Was the statistical analysis appropriate for the study design and type of outcome indicators? Yes
  8.1. Were statistical analyses adequately described and the results reported appropriately? Yes
  8.2. Were correct statistical tests used and assumptions of test not violated? Yes
  8.3. Were statistics reported with levels of significance and/or confidence intervals? Yes
  8.4. Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)? N/A
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? Yes
  8.6. Was clinical significance as well as statistical significance reported? Yes
  8.7. If negative findings, was a power calculation reported to address type 2 error? N/A
9. Are conclusions supported by results with biases and limitations taken into consideration? Yes
  9.1. Is there a discussion of findings? Yes
  9.2. Are biases and study limitations identified and discussed? Yes
10. Is bias due to study's funding or sponsorship unlikely? Yes
  10.1. Were sources of funding and investigators' affiliations described? No
  10.2. Was the study free from apparent conflict of interest? Yes