Glycaemic Variability and Urinary Albumin Excretion in Type 2 Diabetes Mellitus: A Retrospective Observational Study

Abstract

Background: Albuminuria is an early and clinically meaningful expression of diabetic kidney involvement. Mean HbA1c reflects average glycaemic exposure, but it does not fully capture long-term oscillation in glycaemic control. Whether visit-to-visit HbA1c variability parallels urinary albumin excretion in routine general-medicine practice remains a practical question.

Objective: To evaluate the association between retrospective HbA1c variability and urinary albumin excretion rate (UAER) among patients with type 2 diabetes mellitus.

Materials and Methods: This retrospective observational study included 100 patients with type 2 diabetes mellitus evaluated in the Department of General Medicine between June 2025 and January 2026. Three consecutive annual HbA1c values were used to calculate mean HbA1c, standard deviation, and coefficient of variation (CV). UAER was classified as normoalbuminuria (<30 mg/24 h), microalbuminuria (30-300 mg/24 h), and macroalbuminuria (>300 mg/24 h). Group comparisons were performed using analysis of variance and chi-square tests. Spearman correlation assessed the relation of UAER with glycaemic, renal, and blood-pressure variables.

Results: The cohort had a mean age of 59.52 ± 8.06 years, with equal sex distribution. Normoalbuminuria, microalbuminuria, and macroalbuminuria were observed in 29%, 39%, and 32% of patients, respectively. Mean HbA1c increased from 7.24% in normoalbuminuria to 10.32% in macroalbuminuria (p<0.001). HbA1c CV also rose across the same groups (2.41% to 4.31%, p<0.001). Across HbA1c CV tertiles, mean UAER increased from 56.67 ± 41.79 to 559.41 ± 270.71 mg/24 h, while mean eGFR declined from 79.94 ± 15.52 to 43.50 ± 13.55 mL/min/1.73 m² (both p<0.001). Macroalbuminuria was concentrated in the high HbA1c CV tertile (82.4%).

Conclusion: Higher mean HbA1c and greater visit-to-visit HbA1c variability were strongly associated with higher UAER and lower eGFR in type 2 diabetes mellitus. Glycaemic consistency, not only point-in-time HbA1c control, may deserve greater emphasis during diabetic kidney disease risk assessment.