Efficacy of Vitamin C with Iron Supplementation in Iron Deficiency Anemia Patients: A Systematic Review and Meta-Analysis
Notice bibliographique
Résumé
Background Oral iron supplementation is one of the mainstays of treatment for iron deficiency anemia (IDA) but can be complicated by poor absorption. Vitamin C is hypothesized to increase the acidity of the GI tract and enhance the conversion of non-absorbable ferric iron (Fe 3+) to its absorbable ferrous (Fe 2+) state for improved absorption and is often prescribed with iron. However, whether vitamin C supplementation translates to clinically relevant differences, such as sufficient improvements in hemoglobin, remains unclear and a synthesis of available evidence is lacking. Therefore, the present systematic review and meta-analysis aims to compare oral iron with or without vitamin C supplementation in patients with IDA. Methods MEDLINE, EMBASE, Web of Science and Cochrane Central Register of Controlled Trials were searched from database inception to July 2023 for randomized controlled trials (RCTs) and non-randomized studies (NRSs) that investigated the use of oral iron supplements with vitamin C compared to oral iron supplements only in patients with IDA. Title & abstract, full text review and data extraction were conducted independently and in duplicate. The primary outcome was the change in serum hemoglobin levels in g/dL. Secondary outcomes include change in serum ferritin, change in transferrin saturation, change in reticulocyte percentage, and incidence of adverse events including constipation, nausea/vomiting, GI upset and poor taste. The Mantel-Haenszel fixed effects model was utilized for the meta-analysis. The calculated effect sizes were represented by odds ratios (OR) and mean differences (MD) for binary endpoints and continuous endpoints, respectively, with 95% confidence intervals (CI). Results 2231 studies were retrieved from electronic databases. 12 RCTs and one prospective cohort study comprising 2240 patients were included. There was a small but statistically significant increase in serum hemoglobin level (MD 0.14 g/dL [95%CI 0.08, 0.20]) and serum ferritin levels (MD 3.23 µg/L [95%CI 1.63, 4.84]) in the iron + vitamin C group compared to the iron only group. There was a greater reduction in serum transferrin saturation associated with vitamin C supplementation (MD -2.01% [95%CI -3.31, -0.71%]) but the pool of evidence consists of only two studies. Reticulocyte percentage (MD 0.22% [95%CI 0.08, 0.36]) was higher in the iron + vitamin C group than in the iron only group. There were no significant differences between the iron + vitamin C group and the iron only group in overall incidence of adverse effects (OR 0.71 [95%CI 0.50, 1.00]), constipation (odds ratio (OR) 0.83 [95%CI 0.35, 1.96]), or nausea/vomiting (OR 0.80 [95%CI 0.52, 1.24]). The risk of GI upset is lower in the iron + vitamin C group (OR 0.40 [95%CI 0.18, 0.92]). Nevertheless, only three primary studies reported on incidence of adverse events. Conclusion The addition of vitamin C to iron supplementation in the management of IDA was associated with a statistically significant, but likely clinically unimportant, increase in serum hemoglobin of 0.14 g/dL. Similarly, a statistically significant increase in serum ferritin levels by 3.23 µg/L was observed, but its clinical relevance remains uncertain. A strength of the present analysis is the number of RCTs included; however, its conclusions are limited by the heterogeneity of interventions (e.g. different formulations/dosage) across studies. Our results do not provide strong evidence for adding vitamin C to iron supplementation.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,009 | 0,019 |
| Méta-épidémiologie (sens strict) | 0,002 | 0,001 |
| Méta-épidémiologie (sens large) | 0,020 | 0,035 |
| Bibliométrie | 0,005 | 0,006 |
| Études des sciences et des technologies | 0,001 | 0,001 |
| Communication savante | 0,003 | 0,001 |
| Science ouverte | 0,002 | 0,001 |
| Intégrité de la recherche | 0,003 | 0,002 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,004 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».