Rationale for Raising Current Clinical Practice Guideline Target for Serum 25-Hydroxyvitamin D in Chronic Kidney Disease
Bibliographic record
Abstract
BACKGROUND: Vitamin D repletion is recommended for secondary hyperparathyroidism (SHPT) and associated vitamin D insufficiency (VDI) in chronic kidney disease (CKD), but optimal levels of serum total 25-hydroxyvitamin D remain undefined. Clinical practice guidelines target sufficiency, whereas recent data indicate that higher levels are required to control the elevation of intact parathyroid hormone (iPTH) as CKD advances. This secondary analysis of 2 randomized controlled trials seeks to identify the minimum level of mean serum 25-hydroxyvitamin D required to control SHPT arising from VDI in stage 3 or 4 CKD. METHODS: Adult subjects (n = 429) with SHPT, VDI, and stage 3 or 4 CKD were stratified by stage and treated daily with either extended-release calcifediol (ERC) or placebo in 2 identical, parallel, randomized, double-blind studies. After treatment for 26 weeks, all subjects were ranked by the level of serum total 25-hydroxyvitamin D and divided into quintiles in order to examine the relationships between the degree of vitamin D repletion and the associated changes in plasma iPTH, serum bone turnover markers, calcium, phosphorus, intact fibroblast growth factor 23 (FGF23) and vitamin D metabolites, estimated glomerular filtration rate (eGFR), and urine calcium:creatinine (Ca:Cr) ratio. RESULTS: Progressive increases in serum 1,25-dihydroxyvitamin D and reductions in plasma iPTH and serum bone turnover markers were observed as mean posttreatment serum 25-hydroxyvitamin D rose from 13.9 ng/mL (in Quintile 1) to 92.5 ng/mL (in Quintile 5), irrespective of CKD stage. Mean serum calcium, phosphorus and FGF23, eGFR, and urine Ca:Cr ratio (collectively "safety parameters") did not significantly change from Quintile 1. Suppression of iPTH and bone turnover markers was not observed until serum 25-hydroxyvitamin D rose to at least 50.8 ng/mL (Quintile 3). CONCLUSION: ERC therapy produced exposure-dependent reductions in plasma iPTH and bone turnover markers only when mean serum total 25-hydroxyvitamin D reached at least 50.8 ng/mL, indicating that current targets for vitamin D repletion therapy in CKD are too low. Gradual elevation of mean serum 25-hydroxyvitamin D to 92.5 ng/mL was not associated with significant adverse changes in safety parameters.
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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 | 0.066 | 0.097 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.002 | 0.003 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.002 | 0.004 |
| Scholarly communication | 0.005 | 0.003 |
| Open science | 0.005 | 0.002 |
| Research integrity | 0.012 | 0.015 |
| Insufficient payload (model declined to judge) | 0.006 | 0.002 |
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".