The association between homocysteine and systemic sclerosis: A review of the literature and meta-analysis.

Objectives: The main objective of this study was to summarize the existing evidence and quantitatively evaluate whether serum/plasma levels of homocysteine (Hcy) were associated with sclerosis (SSc) diseases by performing a meta-analysis of previous studies.Methods: PubMed, Elsevier ScienceDirect and Cochrane Library databases were used to obtain all relative published literatures. Stata version 11.0 (StataCorp, College Station, TX) was used for statistical analysis. The effect size of each study was calculated by the standardized mean difference (SMD) with 95% confidence interval (CI) or quartiles.Results: A total of eight studies including 475 cases and 265 controls were finally included in this meta-analysis. We found significant between-study heterogeneity and conducted analyses using random-effects models. No significant association was found between the serum levels of Hcy and SSc (pooled SMD=1.382mol/L, 95%CI=-0.442 to 3.206, p=.137), but there are two outlier studies that deviate significantly from most other studies, which made it difficult to generalize these results. After excluding these two studies, six studies were included in the meta-analysis. The results showed that the serum levels of Hcy in SSc were significantly higher than that in healthy controls (pooled SMD=1.182mol/L, 95%CI=0.230-2.134, p=.015).Conclusion: Serum/plasma levels of Hcy in SSc diseases were higher than that in healthy controls.