ObjectiveTo explore the correlation between serum transforming growth factor-β1(TGF-β1), mothers against decapentaplegic homolog 2(Smad2), and mothers against decapentaplegic homolog 3(Smad3) levels and the degree of renal function impairment and prognosis in patients with diabetic kidney disease (DKD).MethodsA total of 83 patients with DKD who were admitted to our hospital from January 2022 to December 2024 were selected for this study. A general information questionnaire was used to collect the general information of the patients, and the measurement results of serum TGF-β1, Smad2, and Smad3 were also collected.The Pearson correlation analysis method was applied to analyze the correlation between serum indicators and renal function indicators.The entire study was followed up for 12 months, and the independent risk factors for the prognosis of DKD patients were explored and analyzed using the multivariate Logistic regression model.ResultsAs the degree of renal function impairment increases, the levels of serum TGF-β1, Smad2, and Smad3 gradually rise (all P＜0.05). These three indicators had a positive correlation with serum creatinine (Scr) and 24 hours urine protein (24 h UP) quantification (all P＜0.05), while they showed a negative correlation with estimated glomerular filtrations rate (eGFR)(all P＜0.05). They were independent risk factors for poor prognosis in patients with DKD (all P＜0.05).ConclusionSerum TGF-β1, Smad2, and Smad3 levels are closely related to the degree of renal function impairment in DKD patients and are important biological markers for predicting the adverse prognosis of patients.