Evaluation of the frequency of normal to mildly increased albuminuria, in patients with type 2 diabetes with CKD referred to clinics of Ahwaz teaching Hospitals in the years 2014–2020

Background
Diabetic nephropathy is the main cause of impaired renal function and chronic kidney disease (CKD) in diabetic patients.

Objectives
The aim of this study was to estimate the prevalence and characteristics of normal to mildly increased albuminuria in type 2 diabetes mellitus (T2DM) patients with chronic kidney disease.

Material and methods
This retrospective study was performed on 310 patients diagnosed with T2DM and renal insufficiency (eGFR < 60 mL/min/1.73 m2) referred to Ahvaz hospitals between 2014–2020. Demographic and clinical data, as well as laboratory parameters, were extracted from patients’ medical records. After considering the inclusion criteria (adult diabetic patients with renal failure (eGFR < 60 mL/min/1.73 m2) and exclusion criteria (patients with hypertension, cardiovascular disease (ischemic heart disease, chronic heart failure, peripheral vascular disease, cerebrovascular disease), urinary tract infection, anatomical disorders of the urinary tract, kidney stones, benign prostatic hyperplasia, history of diuretic use, nephrotoxic drugs such as ACEI, ARB, NSAIDs, physiological causes of albuminuria such as prolonged standing and exercise, systematic disease (e.g. systemic lupus erythematosus) and dialysis patients), in terms of age, gender and duration of diabetes and lipid profile and retinopathy and neuropathy and HbA1C, patients were divided into three groups based on the severity of albuminuria (albumin-to-creatinine ratio): normal to mildly increased albuminuria (ACR < 30 mg/g), moderately increased (ACR: 30–300 mg/g) and severely increased (ACR > 300 mg/g).

Results
A total of 310 T2DM patients with a mean age of 57.2 ± 9.5 years, including 164 women (52.9%) and 146 men (47.1%), participated in the study, of which 4 patients (1.3%) had normal albuminuria, 76 patients (24.5%) had mildly increased albuminuria, 142 patients (45.8%) had moderately increased albuminuria, and 88 patients (28.4%) had severely increased albuminuria. Individuals with normal to mildly increased albuminuria compared with moderate to severe albuminuria had lower duration of diabetes, age, creatinine, retinopathy, neuropathy, HbA1c, LDL, Tchol (p < 0.001), higher GFR (p < 0.001) and lower TG (p = 0.003), while HDL-c (p = 0.07) and patients’ gender (p = 0.2) were not significantly different. Examination of the odds ratio (OR) showed that retinopathy, high age and high HbA1c levels had the greatest effect on the development of moderate to severe albuminuria, whereas increased GFR and a small increase in LDL had a preventive effect on moderate to severe albuminuria.

Conclusions
The results of the present study showed that although the majority of diabetic patients with renal insufficiency had moderate to severe albuminuria, a considerable proportion of patients with diabetes and renal insufficiency had normal to mildly increased albuminuria. This can limit the role of microalbuminuria as a screening tool to detect the onset of diabetic nephropathy.