Ascorbic Acid Prevents Contrast-Mediated Nephropathy in Patients With Renal Dysfunction Undergoing Coronary Angiography or Intervention
Bibliographic record
Abstract
BACKGROUND: Contrast agents can cause a reduction in renal function that may be due to the generation of reactive oxygen species. Conflicting evidence suggests that administration of the antioxidant acetylcysteine prevents this renal impairment. The action of other antioxidant agents has not been investigated. METHODS AND RESULTS: We conducted a randomized, double-blind, placebo-controlled trial of ascorbic acid in 231 patients with a serum creatinine concentration > or =1.2 mg/dL who underwent coronary angiography and/or intervention. Ascorbic acid, 3 g at least 2 hours before the procedure and 2 g in the night and the morning after the procedure, or placebo was administered orally. Contrast-mediated nephropathy was defined by an absolute increase of serum creatinine > or =0.5 mg/dL or a relative increase of > or =25% measured 2 to 5 days after the procedure. Contrast-mediated nephropathy occurred in 11 of the 118 patients (9%) in the ascorbic acid group and in 23 of the 113 patients (20%) in the placebo group (odds ratio [OR], 0.38; 95% confidence interval [CI], 0.17 to 0.85; P=0.02). The mean serum creatinine concentration increased significantly in the placebo group (from 1.36+/-0.50 to 1.50+/-0.54 mg/dL, P<0.001) and nonsignificantly in the ascorbic acid group (from 1.46+/-0.52 to 1.52+/-0.64 mg/dL, P=0.07). The mean increase in serum creatinine concentration was greater in the placebo group than in the ascorbic acid group (difference of 0.09 mg/dL; 95% CI, 0.00 to 0.17; P=0.049). CONCLUSIONS: Prophylactic oral administration of ascorbic acid may protect against contrast-mediated nephropathy in high-risk patients undergoing a coronary procedure.
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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 | 0.001 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.002 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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".