Early identification of diabetic kidney disease (DKD) remains important because of its association with adverse renal outcomes in patients with diabetes mellitus (DM). A systematic review and meta-analysis published in Frontiers in Endocrinology evaluated the association between serum fibroblast growth factor 23 (FGF23) levels and DKD.

The analysis followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and searched Cochrane Library, PubMed, Embase, and Web of Science through October 23, 2025. Nine observational studies involving 3,799 participants were included. Methodological quality was assessed using the Newcastle-Ottawa Scale.

Findings

• Serum FGF23 levels were significantly higher in patients with DKD than in those without DKD (standardized mean difference [SMD] = 1.144; 95% confidence interval [CI], 0.361-1.928; p=0.004).
• The pooled odds ratio (OR) for DKD associated with elevated FGF23 levels was 1.136 (95% CI, 0.656-1.968), which was not statistically significant (p=0.649).
• Substantial between-study heterogeneity was observed across analyses (I² >80%).
• Subgroup analyses by geographic region, control type, publication year, DM type, and DKD stage did not fully explain the observed heterogeneity.
• Sensitivity analyses supported the robustness of the continuous variable findings.

Elevated FGF23 levels were observed more frequently in patients with DKD than in non-DKD controls across included studies. Interpretation of the association remains limited by substantial heterogeneity and the lack of statistically significant findings in dichotomous variable analyses.