Prevalence, course and risk factors of diabetic nephropathy in type-2 diabetes mellitus

Abstract

Contrary to the well-known features of diabetic nephropathy (DNP) in type-1 diabetic patients (pts), the prevalence, course and risk factors of DNP in in type-2 diabetic pts are not clear. The aim of the present study was to assess the prevalence of microalbuminuria (MA) and macroalbuminuria (MAA), their relationship with other diabetic complications and with some known cardiovascular risk factors in 200 in type-2 diabetic pts (100 females and 100 males). 68 pts (33%) were normalbuminuric (NA), 55 (27.5%) had MA and 77 (38.5%) had MAA. There was no significant difference among these three groups in age, BMI or the time actually elapsed since the diabetes and hypertension were diagnosed. BMI was high in each group (28.8 +/- 5.29, 28.0 +/- 5.2 and 29.8 +/- 4.6 kg/m2 mean +/- SD). 65% of pts with NA, 77% of those with MA and 81% of pts with MAA had hypertension. MAA pts were more frequently smokers and former smokers, than MA and NA pts (56% vs 32% and 22%). Average GRF values (ml/min/1.73 m2) were 71.9 +/- 26.8 in NA pts, 82.3 +/- 36.8 in MA pts and 56.3 +/- 32 in MAA pts. There was no significant correlation between the urinary albumin excretion (UAE) and glycemic control, serum (se) cholesterol and se HDL cholesterol. At the same time UAE showed a significant positive correlation with se trigliceride (P < 0.01), se uric acid (P < 0.01) and se creatinine (P < 0.01) while a significant negative correlation was found with GFR (P < 0.01). Diabetic non-proliferative retinopathy (RP) was detected even in NA pts (27%) while 51% of MAA pts were without RP. 56% of NA pts, 57% of MA pts and 93% of MAA pts had macroangiopathy.

Conclusions: (1) renal function can be impaired even in type-2 diabetic pts with NA and MA, (2) well-known cardiovascular risk factors seem to have a close relation with renal damage in type-2 diabetes (3) renal lesions in type-2 diabetic pts may be caused by diseases other than diabetes (e.g. arteriosclerosis, hypertension) (4) unlike in type-1 diabetes, where the strict glycemic control is the main preventive factor of DNP, in type-2 diabetes, the control of hypertension, hyperlipidemia, obesity, hyperuricemia may have priority.