The Impact of Type 2 Diabetes Mellitus on Renal Function: Assessment Using the CKD-EPI 2021 Equation in Derna City, Libya

Abstract

Long‑standing type 2 diabetes mellitus (T2DM) is a major risk factor for diabetic kidney disease and chronic kidney disease (CKD), yet early diagnosis remains difficult because serum creatinine often stays normal until substantial renal tissue is lost. Local data in Derna, Libya, are scarce. This case‑control study evaluated the CKD‑EPI 2021 race‑free equation for early detection of renal impairment in 77 T2DM patients and 20 healthy controls recruited from the Cardiac and Diabetes Center in Derna. Fasting glucose, HbA1c, serum urea, and serum creatinine were measured, and eGFR was calculated using the 2021 equation. Diabetic patients had significantly lower eGFR than controls (98.5 ± 12.8 vs. 112.8 ± 11.4 mL/min/1.73 m²; p < 0.001). 13.0% of patients were in Stage 2–3 CKD despite normal creatinine values. Age was the strongest predictor of eGFR decline (r = −0.654; p < 0.001), while HbA1c showed no cross‑sectional correlation (r = −0.062; p = 0.592). Smoking status did not influence eGFR in either group. These findings demonstrate that the CKD‑EPI 2021 equation unmasks early renal impairment missed by creatinine alone and support routine eGFR reporting, particularly for older patients, in Libyan diabetes care.