Gut microbiota in Chinese and Japanese patients with cardiovascular diseases: a systematic review and meta-analysis

BACKGROUND: Cardiovascular disease (CVD) is a major threat to public health. OBJECTIVE: Compare the gut microbial composition between Chinese and Japanese patients with cardiovascular diseases and healthy subjects. STUDY SELECTION: Observational studies with Chinese and Japanese populations. Reviews, duplicate, book chapters, and other irrelevant studies were excluded. DATA EXTRACTION: Independent searching by two investigators (LLJ, HJL). DATA SYNTHESIS: Data from eleven studies (with 960 subjects) were included for the meta-analysis. The meta-analysis showed that the abundance of Firmicutes in patients with cardiovascular disease was [ES=0.42, 95%CI, (0.34, 0.50), P<.01], while the abundance of Firmicutes in control subjects was [ES=0.36, 95%CI, (0.23, 0.49), P<.01] (ES: effect size). When compared to control subjects, the differential expression of Firmicutes abundance in patients with CVDs was [MD = 15.21, 95%CI (8.95, 21.48), P<.01] (MD: mean difference). The ratio of Firmicutes abundance in patients with CVDs to the control subjects was [RR=1.28, 95%CI (0.98, 1.67), P=.07]. The ratio of Firmicutes in coronary heart disease (CHD) patients and controls was [RR=1.42, 95%CI (1.05, 1.94), P=.02]. Firmicutes/Bacteroidetes ratio is [OR=1.64 95%CI (1.11, 2.42), P=.01]. CONCLUSION: Our data show that patients with cardiovascular disease had higher levels of gut Firmicutes when compared to healthy controls. In addition, gut microbial dysbiosis was present in patients with cardiovascular diseases. LIMITATIONS: Due to limited quality and quantity of selected studies, conclusions from the current study need to be validated by future studies. CONFLICT OF INTEREST: None.