'Progressive diabetic nephropathy. How useful is microalbuminuria?: contra'

Abstract

The concept of microalbuminuria has been central to the development of clinical practice and research in the area of diabetic kidney disease (DKD). However, in recent times, the value of a paradigm of DKD based solely on microalbuminuria has been questioned. Although both the absolute level and rate of change of microalbuminuria are linked to the development and progression of DKD, microalbuminuria on its own lacks the necessary sensitivity or specificity to accurately predict kidney outcomes for people with diabetes. The development of microalbumiuria can no longer be viewed as a committed and irreversible stage of DKD, as spontaneous remission is now reported as a common occurrence. In addition, the absence of microalbuminuria or its progression to proteinuria does not signify that an individual patient is safe from a progressive decline in glomerular filtration rate (GFR). Furthermore, although reductions in albuminuria within the microalbuminuric range can be linked to a slower GFR decline in observational studies, this relationship has not been robustly demonstrated in intervention studies. Conclusions regarding the kidney health of individuals with diabetes will continue to be flawed if an inappropriate emphasis is placed on the presence or absence of albuminuria or changes in albuminuria within the microalbuminuric range. This has important implications in terms of undermining the value of microalbuminuria as a surrogate renal end point for intervention trials. There is a need to develop broader models of progressive DKD that include novel pathways and risk markers apart from those related to the traditional 'albuminuric pathway' to renal impairment.