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 sub-jects. 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 coro-nary 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 dis-ease 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 stud-ies, conclusions from the current study need to be validated by future studies.