Validity of Phosphorus Intake Assessment Tools in CKD and Dialysis Populations
Bibliographic record
Abstract
Background: Accurate dietary assessment of phosphorus intake is essential for managing hyperphosphatemia in chronic kidney disease. Clinicians often rely on self-reported data which may be unreliable. This review summarizes evidence on the realiability and validity of phosphorus intake assessment tools in patients with chronic kidney disease or ondergoing dialysis. Methods: We performed a literature search in PubMed and Google Scholar from inception to April 2025, using MeSH terms for “food frequency”, “dietary recall”, “phosphate”, “chronic kidney disease”, “end-stage kidney disease” “dialysis”, “surveys” and “questionnaires”. We included studies with assessment of either validity or reliability of the tools. Data was summarized descriptively reporting quantitative measurements. Results: We identified 5 studies (543 patients). Key characteristics of the studies included and their implications for clinical use are reported in the table. All studies were from different countries. Participants were older than 18 years. Four studies included people on at least one dialysis modality, while one study only included people with moderate to advanced chronic kidney disease but no dialysis patients. The tools comprised food frequency questionnaires (FFQs), short FFQs (SFFQs), and phosphorus knowledge instruments combined with food intake report. Two studies used self-administered tools. All studies found weak to moderate correlations between dietary intake and serum phosphorus or nutrient biomarkers, with questionnaire formats ranging from 31 to 154 food items. Conclusion: All tools showed accuracy limitations, especially among elderly or multi-morbid patients. Literature addressing the accuracy of self-reported intake warns of systematic underreporting, notably in patients with advanced disease or lower health literacy. This implies a need for cautious interpretation of patient-reported phosphorus intake and consideration of supplemental strategies—like biochemical monitoring, dietitian interviews, or digital tracking—for a more accurate evaluation. We are converting this analysis into a systematic review using rigorous, evidence-based methods.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.061 | 0.230 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.004 | 0.005 |
| Bibliometrics | 0.011 | 0.013 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.004 | 0.004 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.002 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".