P. Sathya Murthy1, Vamsi Krishna Makkena2, Muthaiah Kothandaraman Sudhakar3

Diabetes mellitus is one of the most prevalent metabolic diseases which is characterised by elevated blood sugar levels. Type 2 diabetes mellitus constitutes about 90 percent of this group. Untreated DM leads to many complications which are traditionally classified as acute and chronic. The microvascular complications include retinopathy, nephropathy and peripheral neuropathy. Diabetic nephropathy is the most common cause for dialysis and end-stage renal failure across the world. Diabetic nephropathy usually starts with microalbuminuria (UAE 30-300 mg/dL) followed by macroalbuminuria (UAE > 300 mg/dL) and eventually there is progressive loss of renal function by tissue scarring leading on to end-stage renal disease. However, in type 2 DM, there can be a group of patients who can have impaired renal function without albuminuria (UAE<30 mg/ day).
This is being called as “non-albuminuric renal failure”. Reduced GFR in long duration diabetic patients with normal urine albumin excretion have been reported in increasing frequency. There are very few Indian studies which have been done on this group of type 2 diabetic patients. Hence, this study is aimed to evaluate the clinical profile of non-albuminuric renal insufficiency in type 2 diabetes mellitus.
To study the clinical profile of non-albuminuric renal insufficiency in type 2 DM.
The study population included 97 patients with non-albuminuric (urine microalbumin less than 30 mg/day, renal insufficiency (GFR less than 60 mL/min. as per Cockcroft–Gault formula) and are diabetic (type 2) admitted in the Department of General Medicine and Nephrology. Patients with comorbidities other than diabetes which can cause renal insufficiency were excluded from the study.
A detailed history was taken and clinical assessment was done for all patients. All patients underwent a panel of tests which included complete blood count, blood urea nitrogen, serum creatinine, electrolytes (Na, Cl, K, HCO3), LFT, urine routine examination, urine microalbumin, urine culture, USG abdomen, ECG, fundus assessment, calcium, phosphorus, uric acid. GFR was calculated in all the study population with Cockcroft–Gault formula and the study group was divided into different stages of CKD.
Categorical variables were expressed as number (%) and continuous variables expressed as mean (SD, Range). Descriptive statistics (age, gender, comorbid illness,) were explained using bar charts, pie diagrams. Correlation between two variables was checked using the Pearson's correlation coefficient method (HbA1c, GFR, Microalbumin).
In the present study, a total of 97 patients met the inclusion criteria.
Among these 97 patients, 62 are male and 35 are female. The minimum and maximum age of the patient in the study group is 43 & 85. The mean age observed in the present study is 61.85. Among the study group of 97 participants, 68 (70.1 %) had trace proteinuria in routine urine examination, while 29 (29.9 %) had negative proteinuria in routine urine examination. The mean HbA1C value in the trace proteinuria is 9.80, and the mean value of HbA1c in the negative proteinuria group is 10.67. In the study population, 9 patients (9.27%) are under CKD-3 as per KDOQI classification of the stages of CKD, 59 (60.8 %) are under CKD-4, 29 (29.89 %) are under CKD-5. In the study group of 97 patients, 54 had non-proliferative diabetic retinopathy, 43 had proliferative diabetic retinopathy. The minimum and maximum duration of diabetes in years in our study is 5 & 37. The mean value is 13.98.
Non-albuminuric renal insufficiency seems to be more prevalent among males more than 60 years of age. In this group, most of them were in CKD stage 4. Severity of the retinopathy correlated with the degree of renal insufficiency. Uncontrolled diabetes mellitus status (larger HbA1c value) correlated with proliferative diabetic retinopathy than the larger duration of diabetes mellitus. Patients with higher HbA1c values had negative proteinuria. Hence non-albuminuric renal insufficiency is a unique clinical entity which should be kept in mind while managing type 2 DM patients.