Serum Isthmin-1 and Atherogenic Index of Plasma as Biomarkers Associated with Albuminuria Severity in Type 2 Diabetes Mellitus

<ns5:p>Background One of the major diabetic complications and the third leading cause of death after cardiovascular disorders and oncological in patients with type 2 is diabetic nephropathy, Novel biomarkers that represent early renal damage are required to speed up diagnosis and monitoring. Isthmin-1 a newly identified adipokine plays role in glucose and lipid metabolism. Isthmin-1 implicated in endothelial cell dysfunction and renal fibrosis, increases with albuminuria stage. The present study aims to evaluate the atherogenic index of plasma (AIP) and serum Isthmin-1 as a Biomarkers associated with albuminuria severity Diabetic in type 2 diabetes mellitus patients classified according to albuminuria level. Methods A cross-sectional analytical study was conducted in a specialist endocrine and diabetes research center in Baghdad, Iraq, between October 2024 and March 2025. Ninety patients with type 2 diabetes mellitus were divided into three groups according to their urine albumin/creatinine ratio: normal albuminuria, microalbuminuria, and macroalbuminuria. Isthmin-1 was evaluated by ELISA. Atherogenic index of plasma was calculated based on lipid profile, The estimated glomerular filtrating rates were calculated using the Chronic Kidney Disease Epidemiology Collaboration model, and laboratory measurements (asting blood glucose, HbA1C, lipid profile and renal functions) were measured using standard automated biochemical methods. Results Serum Isthmin-1 significantly increased (p < 0.0001) from normalbuminuria (195.39 ± 48.80 pg/mL) to microalbuminuria (479.26 ± 83.62 pg/mL) and macroalbuminuria (729.19 ± 73.58 pg/mL). AIP demonstrated a modest but significant increase across albuminuria stages, the normoalbuminuria group had considerably lower AIP evels (0.05 ± 0.32) than the microalbuminuria group (0.15 ± 0.27), whereas the macroalbuminuria group had highest values (0.25 ± 0.27). Conclusions Both atherogenic index of plasma and Ism-1 levels were increased significantly with albuminuria severity in type 2 diabetes mellitus patients, AIP suggesting increasing atherogenic dyslipidaemia with renal while isthmin-1 Isthmin-1 showing the strongest between-group association with worsening albuminuria.</ns5:p>