Objective To explore the influence of compstatin on the serum levels of human monocyte chemoattractant protein-1(MCP-1)and placental growth factor(PIGF)in patients with diabetic retinopathy(DR).Methods A prospective clinical study was conducted.One hundred and ninety-three patients with DR treated at Xi'an First Hospital from May 2020 to August 2022 were selected as the study objects.All the patients were treated with compstatin injection.One month after the treatment,the clinical efficacy was evaluated;the patients were categorized into a poor efficacy group(27 cases)and a good efficacy group(166 cases).There were 15 men and 12 women in the poor efficacy group;they were(53.14±9.45)years old;their DR course was(12.63±2.89)years.There were 86 men and 80 women in the good efficacy group;they were(51.86±9.72)years old;their DR course was(10.82±3.51)years.The clinical data and serum levels of MCP-1 and P1GF were compared between the two groups.The logistic regression was used to analyze the risk factors of the effect of compstatin injection for the patients with DR and to assess the efficacy of serum MCP-1 and P1GF in the prediction of the treatment effect.t and x2 tests were applied.Results The diabetes mellitus duration and levels of glycosylated hemoglobin(HbA1c),vascular endothelial growth factor(VEGF),MCP-1,and PIGF in the poor efficacy group were higher those in the good efficacy group[(12.63±2.89)years vs.(10.82±3.51)years,(9.03±0.81)%vs.(8.52±0.94)%,(102.47±21.57)ng/L vs.(89.65±20.18)ng/L,(906.49±83.52)ng/L vs.(684.53±70.42)ng/L,and(75.83±9.25)ng/L vs.(62.01±8.43)ng/L],with statistical differences(t=2.541,2.662,3.032,14.786,and 7.793;all P<0.05).The multifactorial regression analysis showed that HbA1C,VEGF,MCP-1,and PIGF were risk factors affecting the treatment effect of compstatin injection for the patients with DR(all P<0.05).The receiver operating characteristics curve analysis revealed that the areas under the curves of MCP-1,PIGF,and their combination in the prediction of the treatment effect of compstatin injection for the patients with DR were 0.833,0.811,and 0.909,respectively.Conclusion The combination of serum MCP-1 and PIGF is effective in predicting the therapeutic effect of compstatin injection for patients with DR.