Johns Hopkins University School of Medicine, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland 21224, USA.
Arthritis Care Res (Hoboken). 2011 Sep;63(9):1295-306. doi: 10.1002/acr.20519.
To assess the effect of vitamin C supplementation on serum uric acid (SUA) by pooling the findings from published randomized controlled trials (RCTs).
A total of 2,082 publications identified through systematic search were subjected to the following inclusion criteria: 1) RCTs conducted on human subjects, 2) reported end-trial SUA means and variance, 3) study design with oral vitamin C supplementation and concurrent control groups, and 4) trial duration of at least 1 week. Trials that enrolled children or patients receiving dialysis were excluded. Two investigators independently abstracted trial and participant characteristics. SUA effects were pooled by random-effects models and weighted by inverse variance.
Thirteen RCTs were identified in the Medline, EMBase, and Cochrane Central Register of Controlled Trials databases. The total number of participants was 556, the median dosage of vitamin C was 500 mg/day, trial size ranged from 8-184 participants, and the median study duration was 30 days. Pretreatment SUA values ranged from 2.9-7.0 mg/dl (Système International d'Unités [SI units]: 172.5-416.4 μmoles/liter). The combined effect of these trials was a significant reduction in SUA of -0.35 mg/dl (95% confidence interval -0.66, -0.03 [P = 0.032]; SI units: -20.8 μmoles/liter). Trial heterogeneity was significant (I(2) = 77%, P < 0.01). Subgroup analyses based on trial characteristics indicated larger reductions in uric acid in trials that were placebo controlled.
In aggregate, vitamin C supplementation significantly lowered SUA. Future trials are needed to determine whether vitamin C supplementation can reduce hyperuricemia or prevent incident and recurrent gout.
通过合并已发表的随机对照试验（RCT）的研究结果，评估维生素 C 补充剂对血清尿酸（SUA）的影响。
通过系统搜索共确定了 2082 篇文献，这些文献需符合以下纳入标准：1）在人体受试者中进行的 RCT；2）报告终试验 SUA 均值和方差；3）采用口服维生素 C 补充剂和同期对照组的研究设计；4）试验持续时间至少为 1 周。排除了纳入儿童或接受透析的患者的试验。两名研究人员独立提取试验和参与者特征。采用随机效应模型对 SUA 效应进行合并，并按倒数方差加权。
在 Medline、EMBase 和 Cochrane 对照试验中心注册数据库中确定了 13 项 RCT。参与者总数为 556 人，维生素 C 的中位剂量为 500mg/天，试验规模从 8-184 名参与者不等，中位研究时间为 30 天。治疗前 SUA 值范围为 2.9-7.0mg/dl（国际单位制[SI]单位：172.5-416.4μmoles/升）。这些试验的综合效果是 SUA 显著降低了-0.35mg/dl（95%置信区间-0.66，-0.03[P=0.032]；SI 单位：-20.8μmoles/升）。试验异质性显著（I(2)=77%，P<0.01）。基于试验特征的亚组分析表明，在安慰剂对照试验中，尿酸降低幅度更大。
总的来说，维生素 C 补充剂显著降低了 SUA。需要进一步的试验来确定维生素 C 补充剂是否可以降低高尿酸血症或预防痛风的发生和复发。
