Urinary NGAL and Conventional Renal Markers in Patients with Type 2 Diabetes Mellitus: A Comparative Cross-Sectional Study at a Nigerian Teaching Hospital

Abstract

Diabetic kidney disease (DKD) is a leading complication of type 2 diabetes mellitus (T2DM); conventional renal markers may not fully capture tubular injury. This study compared demographic, clinical, and conventional renal markers, and urinary neutrophil gelatinase-associated lipocalin (NGAL), between 88 T2DM patients and 44 non-diabetic controls at UITH, Ilorin, Nigeria; examined NGAL's associations with conventional renal markers and clinical characteristics among T2DM participants; and compared the discriminatory performance of NGAL and urinary albumin-to-creatinine ratio (UACR) for reduced eGFR (<60 mL/min/1.73m²). T2DM participants were significantly older than controls and had significantly higher blood pressure and fasting glucose (all p<0.001), with similar hypertension prevalence (86.4% vs 72.7%, p=0.056). Compared with controls, T2DM participants had significantly higher serum creatinine, urinary albumin, UACR and NGAL, and significantly lower urinary creatinine and eGFR (all p≤0.001); median NGAL was approximately 90% higher than in controls (22.85 vs 12.00 ng/mL). Among T2DM participants, NGAL correlated strongly with serum creatinine and UACR, and negatively with eGFR (all p<0.001), and was associated with age and diabetes duration but not sex. Among the 35 of 88 T2DM participants (39.8%) with reduced eGFR, NGAL discriminated this status with AUC 0.852 (95% CI 0.774–0.931), lower than UACR (AUC 0.940, 95% CI 0.895–0.985). NGAL was significantly elevated in T2DM and correlated strongly with conventional renal markers, supporting a potential complementary, rather than an early-detection or predictive, role alongside serum creatinine, eGFR and UACR; the cross-sectional design cannot establish temporal precedence, and larger longitudinal studies are needed before clinical application.