Diagnostic value of urinary exosomes in patients with IgA nephropathy and diabetic kidney disease: a systematic review and meta-analysis.

BACKGROUND: Previous studies have indicated an association between the novel biomarker urinary exosomes and both IgA nephropathy (IgAN) and diabetic kidney disease (DKD). This study aimed to investigate the diagnostic value of urinary exosomes in patients with IgAN and DKD. METHODS: The PubMed, Embase, Cochrane Library, and Web of Science databases were searched to identify eligible studies from their inception to December 4, 2025. Data on sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and their corresponding 95% confidence intervals (95% CI) were extracted and pooled. Diagnostic meta-analysis was performed using Stata software (version 15.0; Stata Corporation, College Station, TX, USA) and Meta-DiSc version 1.4. RESULTS: A total of 22 articles involving 6,482 participants were included. The pooled results showed that for the diagnosis of DKD, urinary exosomes had a sensitivity of 0.86 (95% CI: 0.77-0.92), a specificity of 0.83 (95% CI: 0.75-0.89), a DOR of 31.10 (95% CI: 11.09-87.19), and an area under the curve (AUC) of 0.91. For the diagnosis of IgAN, urinary exosomes had a sensitivity of 0.78 (95% CI: 0.71-0.83), a specificity of 0.70 (95% CI: 0.63-0.77), a DOR of 8.26 (95% CI: 5.03-13.56), and an AUC of 0.81. CONCLUSION: Urinary exosomes showed stronger summary diagnostic performance for DKD than for IgAN. For IgAN, the pooled results support a moderate diagnostic contribution rather than a clearly established clinical role. Standardized prospective studies with prespecified thresholds are needed before routine clinical use can be established. SYSTEMATIC REVIEW REGISTRATION: identifier: CRD420251252373.