Abstract： AIM To analyze the value of serum microribonucleic acid 200a-3p(miR-200a-3p)and microribonucleic acid 30a-5p(miR-30a-5p)expression in the diagnosis of heart failure(HF)and prognosis evaluation of HF patients.METHODS prospective study,131 HF patients admitted to Inner Mongolia Medical University Affiliated Hospital from April 2018 to April 2020 were selected as the study subjects(HF group),131 healthy volunteers undergoing simultaneous physical examination were included as the control group;real-time fluorescence quantitative PCR(qRT-PCR)was applied to determine the expression levels of miR-200a-3p and miR-30a-5p in serum;Spearman correlation analysis was applied to analyze the correlation between serum levels of miR-200a-3p and miR-30a-5p and the severity of condition;receiver operating characteristic was applied to analyze the diagnostic value of serum miR-200a-3p and miR-30a-5p for HF;Logistic regression was applied to analyze the influencing factors of prognosis in HF patients;and Kaplan-Meier survival was applied to analyze the relationship between serum miR-200a-3p and miR-30a-5p expression levels and the prognosis of HF patients.RESULTS Compared with the control group,the expression levels of miR-200a-3p and miR-30a-5p in the serum of the HF group were significantly increased,and the difference was statistically significant(P<0.05);The expression levels of miR-200a-3p and miR-30a-5p in the serum of patients with mild,moderate,and severe HF increased sequentially,and the differences were statistically significant(P<0.05);Spearman correlation analysis showed that the expression levels of miR-200a-3p and miR-30a-5p in serum were positively correlated with the severity of HF patients(rs=0.442,rs=0.564,all P<0.05);The ROC curve analysis results show that the combined diagnosis of miR-200a-3p and miR-30a-5p for HF is more effective than the single indicator diagnosis of miR-200a-3p and miR-30a-5p(P<0.05);Logistic regression analysis found that NT-proBNP,LVEF,LVEDD,miR-200a-3p and miR-30a-5p are prognostic factors for HF patients(Wald)χ2=4.321～128.193,P<0.05);The Kaplan Meier survival analysis results showed that the 3-year survival rate of patients with high expression of miR-200a-3p and miR-30a-5p in serum was lower than that of patients with low expression of miR-200a-3p and miR-30a-5p(both P<0.05).CONCLUSION The expression levels of miR-200a-3p and miR-30a-5p in the serum of HF patients are obviously increased,which are related to the occurrence and prognosis of HF.