Abstract: Objective To investigate the changes in serum microRNA (miR)-92b-5p and miR-148b-3p levels and their role in the progression of type 2 diabetes mellitus (T2DM) to diabetic nephropathy (DN). 
Methods A prospective study was conducted on 400 T2DM patients in our hospital, with 200 non-DN patients as the T2DM group and 200 DN patients as the DN group. The clinical data, serum miR-92b-5p and miR-148b-3p levels of the two groups were compared, and the serum miR-92b-5p and miR-148b-3p levels of patients with different stages in the DN group were compared. The correlation between serum miR-92b-5p and miR-148b-3p levels and clinical stages in the DN group, the interaction between serum miR-92b-5p and miR-148b-3p in the progression of T2DM to DN, and the value of serum miR-92b-5p and miR-148b-3p levels in predicting DN were analyzed. 
Results In the DN group, serum creatinine (SCr) and serum miR-148b-3p levels were higher than those in the T2DM group, and the estimated glomerular filtration rate (eGFR) and serum miR-92b-5p levels were lower than those in the T2DM group (P＜0.05). Serum miR-148b-3p levels in the DN group were higher, and serum miR-92b-5p levels were lower than those in the early stage (P＜0.05). Serum miR-92b-5p levels in the DN group were negatively correlated with clinical stage and serum miR-148b-3p levels were positively correlated with clinical stage (P＜0.05). The positive interaction between low expression of miR-92b-5p and high expression of miR-148b-3p in the progression of T2DM to DN was a submultiplicative model (P＜0.05). The area under the curve (AUC) of miR-92b-5p and miR-148b-3p in predicting T2DM progression to DN was 0.840 and 0.812, respectively, and the combined prediction of the two had the largest AUC (0.911). 
Conclusion Serum miR-92b-5p levels are significantly lower and miR-148b-3p levels are significantly higher in DN patients, which are closely related to the clinical stage of DN. Low expression of miR-92b-5p and high expression of miR-148b-3p contribut to the progression of T2DM to DN. 

Key words: diabetes mellitus, type 2, diabetic nephropathy, microRNA-92b-5p