Kidney injury molecule-1 as a biomarker of diabetic kidney disease in children with type 1 diabetes: a systematic review and quantitative synthesis

Tubulointerstitial damage is a common diabetic kidney disease (DKD) complication caused by diabetes mellitus. However, many patients may not present with albuminuria or impaired glomerular filtration rate (GFR), making it difficult to detect kidney dysfunction. Kidney injury molecule-1 (KIM-1) is an emerging biomarker of early DKD, reflecting tubular injury before glomerular dysfunction. We explored the association between KIM-1 and DKD in children and adolescents with type 1 diabetes (T1D). We included 10 studies with 842 participants published between 2016 and 2025. A literature search of MEDLINE/PubMed, Cochrane Library, and Scopus was conducted from inception through January 5, 2026. The mean difference with a 95% confidence interval (CI) was calculated, and a P-value of <0.05 was considered statistically significant. A quality assessment of the included studies was conducted using the Newcastle-Ottawa Scale. In the meta-analysis of four studies, the urinary KIM-1 (uKIM-1)/creatinine ratio was elevated before changes in estimated GFR (95% CI, 0.02–0.48; P=0.03). This review suggests that uKIM-1/creatinine ratio and uKIM-1 may act as promising tubular biomarkers associated with early kidney injury in pediatric patients with T1D. However, further data are needed to clarify their role in pediatric DKD.