Association of matrix metalloproteinase-9 level with the risk of renal involvement for Henoch-Schönlein purpura in children.

Matrix metalloproteinase-9 (MMP-9) is an enzyme that implicates in the pathogenesis of renal diseases. Henoch-Schönlein purpura nephritis (HSPN) is the most serious long-term complication of Henoch-Schönlein purpura, and it is one of the most common renal diseases in children. There was no any meta-analysis to explore the association of MMP-9 level with the risk of HSPN, and this meta-analysis was performed to evaluate the association between MMP-9 level and HSPN risk in children. A predefined literature search and selection of eligible relevant studies were performed to collect data from electronic databases. Eight articles were identified for the analysis of association between MMP-9 level and HSPN risk in children. In this meta-analysis, urinary MMP-9 level was associated with the risk of HSPN [odds ratio (OR) = 77.21, 95% confidence interval (CI): 54.56-99.86, p < 0.00001]. Furthermore, there was a notably difference for the association of the serum MMP-9 level with HSPN risk (OR = 135.91, 95% CI: 82.54-189.27, p < 0.00001). In conclusion, urinary/serum MMP-9 level is associated with the risk of HSPN. However, the data used for the meta-analysis in this article were from some low-level studies with small samples, and more studies should be performed in the future.