Hemilä Harri, Chalker Elizabeth, de Man Angelique M E
Department of Public Health, University of Helsinki, Helsinki, Finland.
Biological Data Science Institute, Australian National University, Canberra, ACT, Australia.
Front Cardiovasc Med. 2022 Feb 25;9:789729. doi: 10.3389/fcvm.2022.789729. eCollection 2022.
Vitamin C deprivation can lead to fatigue, dyspnea, oedema and chest pain, which are also symptoms of heart failure (HF). In animal studies vitamin C has improved contractility and mechanical efficiency of the heart. Compared with healthy people, patients with HF have lower vitamin C levels, which are not explained by differences in dietary intake levels, and more severe HF seems to be associated with lower plasma vitamin C levels. This meta-analysis looks at the effect of vitamin C on left ventricular ejection fraction (LVEF).
We searched for trials reporting the effects of vitamin C on LVEF. We assessed the quality of the trials, and pooled selected trials using the inverse variance, fixed effect options. We used meta-regression to examine the association between the effect of vitamin C on LVEF level and the baseline LVEF level.
We identified 15 trials, three of which were excluded from our meta-analysis. In six cardiac trials with 246 patients, vitamin C increased LVEF on average by 12.0% (95% CI 8.1-15.9%; < 0.001). In six non-cardiac trials including 177 participants, vitamin C increased LVEF on average by 5.3% (95% CI 2.0-8.5%; = 0.001). In meta-regression analysis we found that the effect of vitamin C was larger in trials with the lowest baseline LVEF levels with = 0.001 for the test of slope. The meta-regression line crossed the null effect level at a baseline LVEF level close to 70%, with progressively greater benefit from vitamin C with lower LVEF levels. Some of the included trials had methodological limitations. In a sensitivity analysis including only the four most methodologically sound cardiac trials, the effect of vitamin C was not substantially changed.
In this meta-analysis, vitamin C increased LVEF in both cardiac and non-cardiac patients, with a strong negative association between the size of the vitamin C effect and the baseline LVEF. Further research on vitamin C and HF should be carried out, particularly in patients who have low LVEF together with low vitamin C intake or low plasma levels. Different dosages and different routes of administration should be compared.
维生素C缺乏可导致疲劳、呼吸困难、水肿和胸痛，这些也是心力衰竭（HF）的症状。在动物研究中，维生素C可改善心脏的收缩力和机械效率。与健康人相比，HF患者的维生素C水平较低，这无法用饮食摄入量的差异来解释，而且更严重的HF似乎与较低的血浆维生素C水平相关。这项荟萃分析探讨了维生素C对左心室射血分数（LVEF）的影响。
我们检索了报告维生素C对LVEF影响的试验。我们评估了试验的质量，并使用逆方差固定效应选项对选定的试验进行汇总。我们使用荟萃回归来检验维生素C对LVEF水平的影响与基线LVEF水平之间的关联。
我们识别出15项试验，其中3项被排除在我们的荟萃分析之外。在6项涉及246例患者的心脏试验中，维生素C使LVEF平均增加了12.0%（95%置信区间8.1 - 15.9%；P < 0.001）。在6项包括177名参与者的非心脏试验中，维生素C使LVEF平均增加了5.3%（95%置信区间2.0 - 8.5%；P = 0.001）。在荟萃回归分析中，我们发现维生素C的作用在基线LVEF水平最低的试验中更大，斜率检验的P = 0.001。荟萃回归线在基线LVEF水平接近70%时与零效应水平相交，LVEF水平越低，维生素C带来的益处越大。一些纳入的试验存在方法学上的局限性。在一项仅包括4项方法学上最可靠的心脏试验的敏感性分析中，维生素C的作用没有实质性变化。
在这项荟萃分析中，维生素C增加了心脏和非心脏患者的LVEF，维生素C作用的大小与基线LVEF之间存在强烈的负相关。应进一步开展关于维生素C与HF的研究，特别是在LVEF低且维生素C摄入量低或血浆水平低的患者中。应比较不同剂量和不同给药途径。
