Correlation Between Chemerin Levels and Diagnosis of Diabetic Nephropathy: A Case-Control Study

Diabetic nephropathy (DN) and diabetic retinopathy (DR) are major microvascular complications of type 2 diabetes mellitus (T2DM), sharing common inflammatory and metabolic pathways. Chemerin, an adipokine involved in inflammation and endothelial dysfunction, may serve as an early biomarker for DN.

To evaluate serum Chemerin levels in type 2 diabetic patients across different stages of albuminuria and to explore its correlation with anthropometric indices and inflammatory markers.

This case-control study included patients with T2DM categorized according to urinary albumin excretion into normoalbuminuria, microalbuminuria, and macroalbuminuria groups. Serum Chemerin levels were measured using ELISA. All participants underwent comprehensive fundus examination after pupillary dilation, and diabetic retinopathy was graded according to standard clinical criteria. Clinical, biochemical, and metabolic parameters were recorded and correlated with albuminuria stages and retinal findings.

Serum Chemerin levels were significantly elevated in diabetic patients with micro- and macro-albuminuria compared with normo-albuminuric patients and healthy controls. Median Chemerin levels increased progressively from 721 ng/mL in the normo-albuminuric group to 1367 ng/mL in the micro-albuminuria group and 2793 ng/mL in the macro-albuminuria group (p < 0.001). Similarly, inflammatory markers demonstrated a stepwise increase with worsening albuminuria; median IL-6 levels rose from 6.34 pg/mL in normo-albuminuric patients to 7.34 pg/mL and 9.6 pg/mL in the micro- and macro-albuminuria groups, respectively, while TNF-α increased from 94 pg/mL to 124 pg/mL and 296 pg/mL across the same groups (p < 0.001). Insulin resistance indices also increased significantly, with median HOMA-IR values rising from 2.45 in normo-albuminuric patients to 3.29 and 4.68 in the micro- and macro-albuminuria groups (p < 0.001). Serum Chemerin showed strong positive correlations with albuminuria (r = 0.85), HOMA-IR (r = 0.85), IL-6 (r = 0.873), and TNF-α (r = 0.813), while demonstrating negative correlations with eGFR and serum albumin. Additionally, the prevalence of diabetic retinopathy increased significantly across albuminuria stages, reaching 82.6% in the macro-albuminuria group (p = 0.001).

Serum Chemerin is significantly elevated in T2DM patients with albuminuria and correlates with both inflammatory markers and retinal microvascular changes, suggesting its potential utility as an adjunct biomarker for diabetic nephropathy and systemic microvascular complications. Fundus examination findings reinforce the parallel progression of diabetic nephropathy and retinopathy, highlighting shared pathogenic mechanisms.