Two retrospective studies in the early 1980s demonstrated that small increases in urinary AER predicted the development of overt nephropathy in people with type 1 diabetes.53,54 This increase in AER was termed microalbuminuria and by consensus, referred to levels of AER of 20–200 µg/min in at lease two of three samples.
By comparison, in healthy subjects, AER ranges from 3 to 11 µg/min54 and routine dipstick tests do not become positive until AER exceeds 200 µg/min (equivalent to total proteinuria of 0.5 g/24h). AG-014699 nmr Subsequent studies showed that microalbuminuria also predicts the development of clinical overt diabetic nephropathy in type 2 diabetes55,56 although it is not as strong a predictor as it is in type 1 diabetes. Persistent microalbuminuria confers an approximately 5-fold increase in the risk of overt nephropathy BTK inhibitor over 10 years in Caucasian persons with type 2 diabetes (approximately 20% cumulative
incidence), compared with a 20 fold increase in risk of nephropathy in type 1 diabetes (approximately 80% cumulative incidence). However, in certain ethnic populations with a high prevalence of type 2 diabetes and diabetic nephropathy, including Pima Indians, Mexican Americans, African Americans, Maoris and Australian Aborigines, microalbuminuria is as strong a predictor of nephropathy as in type 1 diabetes.56–58 The prospective cohort type study of 599 normoalbuminuric people with type 2 diabetes,59 found the baseline AER as a significant predictor of a subsequent decline in renal function as well as the risk of mortality and CVD (median follow-up of 8 years). The usefulness of microalbuminuria as a predictor of overt nephropathy in people with type 2 diabetes
Sitaxentan is shown in the accompanying Table A2 adapted from Parving et al.60 The selected studies are RCTs of varying size and duration that measured the progression of albuminuria as a primary outcome. Parving et al.60 concluded that the studies collectively show the value of microalbuminuria as a predictor of overt nephropathy based on the rate of development of overt nephropathy among the placebo groups. Other prospective studies where the rate of decline in GFR was found to be enhanced in people with microalbuminuria are: Murussi et al.61 (n = 65) – normoalbuminuric people with type 2 diabetes showed a similar rate of decline in GFR over a 10 year period (<2 mL/min per 1.73 m2 per year) as people without type 2 diabetes. In contrast in people with type 2 diabetes and microalbuminuria a GFR decline of 4.7 mL/min per 1.73 m2 per year was recorded. While microalbuminuria in people with type 2 diabetes is an important risk factor for CKD and CVD, it is important to recognize that kidney disease in type 2 diabetes is more heterogeneous than in type 1 diabetes and that a significant number of people will develop CKD (i.e. declining GFR) without development of persistent microalbuminuria as shown in the following studies.