Endocrine Abstracts

Kidney disease occurs in diabetic patients during disease course in time. Diabetes duration, co-morbid diseases, presence of retinopathy, family history of diabetic nephropathy (DN) predict kidney involvement. Although DN is the initial diagnosis in diabetics with proteinuria, other diseases like primary glomerulonephritis (GN) could be the reason of kidney involvement. DN is increasing in proportion with the increase in diabetes prevalence, and it has been predicted to continue to increase in the future. We aimed to analyze the biopsy findings of diabetic patients who presented with renal findings apart from DN.

Methods: The study included 47 (30 males, 17 females) diabetic patients who performed kidney biopsy between 2002 and 2016. Biopsy indications were atypical presentation, like hematuria, proteinuria without retinopathy, acceleration in proteinuria, and unexpected deterioration of kidney function.

Results: The mean age of patients was 56.2±11 years, diabetes duration was 6±4 years. Serum creatinine levels were 2.24±1.6 mg/dL, albumin 3.16±0.77 g/dL, urinary protein excretion 7.52±6.9 g/day, HbA1C 6.0±0.81%, CRP 2.83±5.2 mg/dL, total cholesterol 242±102 mg/dL, triglyceride 225±101 mg/dL and LDL cholesterol 160±92 mg/dL. The biopsy indications were nephrotic syndrome (74.5%), asymptomatic urinary abnormality (17%), rapidly progressive kidney disease (6.4%) and nephritic syndrome (2.1%). DN was diagnosed in 18 diabetic patients (38.3%). Others were focal segmental glomerulosclerosis in 5 patients, AA amyloidosis in 5, IgA nephropathy in 4, membranous GN in 3, AL amyloidosis in 3, ANCA-associated GN in 2, membranoproliferative GN in 1, post-infectious GN in 1, hypertensive nephrosclerosis in 1, thrombotic microangiopathy in 1 and nonspecific changes in 3. The patients were divided into two groups as DN and non-DN. There was no significant difference between characteristics of both groups. Only the ratio of diabetic retinopathy in DN group was higher than that of non-DN group (44 vs. 6.9%, P=0.003).

Conclusion: The present study suggests that non-diabetic kidney pathologies may be common in diabetic patients. Therefore, a kidney biopsy may be useful in diabetic patients with atypical presentation. Although diabetic retinopathy was found to be an important predictor for DN, it is not known whether it’s presence can completely differentiate DN from non-diabetic etiologies.