Prognostic value of serum levels of miR-155 and Smad5 in hemodialysis patients with acute renal failure

Objective  To explore the prognostic value of serum levels of miR-155 and Smad5 in hemodialysis (HD) patients with acute renal failure (ARF).

Methods  From August 2018 to July 2019, 120 ARF patients on HD were selected as study group while another 116 healthy subjects as control group; the serum expressions of miR-155 and Smad5 mRNA were detected by quantitative reverse transcriptase-mediated polymerase chain reaction (qRT-PCR). Pearson’s method was utilized for examining the correlation between serum expression levels of miR-155 and Smad5 mRNA and the levels of creatinine and blood urea nitrogen (BUN); Kaplan-Meier method was employed for examining the survival of HD patients with ARF; COX regression for analyzing the prognostic factors; receiver operating characteristic curve (ROC) curve for assessing the predictive value of serum miR-155 and Smad5 mRNA levels.

Results  The levels of serum miR-155, creatinine and BUN were obviously higher in study group than those in control group (P<0.05). And the level of Smad5 mRNA was obviously lower than that in control group (P<0.05). According to Pearson’s correlation analysis, the serum levels of miR-155 and Smad5 mRNA were correlated negatively (r=−0.538, P<0.05). The expression level of serum miR-155 was correlated positively with the levels of creatinine and BUN (r=0.489, 0.532, both P<0.05). The serum expression level of Smad5 mRNA was correlated negatively with the levels of creatinine and BUN (r=−0.475, −0.558, both P<0.05). The serum levels of miR-155, creatinine and BUN were obviously lower in survival group than those in death group (P<0.05). And the expression level of Smad5 mRNA was obviously higher than that in death group (P<0.05). According to Kaplan-Meier survival curve analysis, the survival rate of miR-155 high-expression group was obviously lower than that of low-expression group (χ²=4.219, P=0.040). And the survival rate of Smad5 high mRNA expression group was obviously higher than that of Smad5 low mRNA expression group (χ²=7.590, P=0.006). According to COX regression analysis, miR-155, Smad5 mRNA, creatinine and BUN were risk factors affecting the prognosis of HD patients with ARF (P<0.05). AUC of serum miR-155 in predicting the prognosis was 0.824, AUC of serum Smad5 mRNA 0.851 and AUC of both 0.930, combining both methods was superior to the prediction of serum miR-155 and Smad5 mRNA separately (Z _{combination vs miR-155}=3.543, Z _{combination vs Smad5 mRNA}=4.325, P<0.05）.

Conclusions  A high expression of miR-155 and a low expression of Smad5 are risk factors affecting the prognosis of HD patients with ARF. And a co-detection of miR-155 and Smad5 may better evaluate the prognosis of HD patients with ARF.