ABSTRACT
George Jerums, Sianna Panagiotopoulos and Richard MacIsaac Endocrinology Unit & Department of Medicine, University of Melbourne, Austin Hospital, Studley Rd, Heidelberg, Victoria 3084, Australia,
INTRODUCTION
Microalbuminuria is an early component in a continuum of progressive increases in albumin excretion rate (AER) associated with diabetic nephropathy. The development of microalbuminuria has been equated with incipient nephropathy but microalbuminuria is also a risk factor for macrovascular disease, especially in patients with type 2 diabetes. Recent data suggest that a substantial minority of non-diabetic and diabetic people with impaired glomerular filtration rate (GFR) may not pass through the phase of microalbuminuria. This has led to the concept that both albuminuric and nonalbuminuric pathways contribute to renal impairment in diabetic mephropathy.
This chapter will review the evidence linking changes in AER and GFR, both temporally as well as causatively in people with microalbuminuria. The data presented are based on a review of publications over the last 10 years, identified by the Ovid search engine, using the key words ‘microalbuminuria’ and ‘GFR’.
Additional publications were found by searching for GFR data in the placebo or untreated arm of clinical trials lasting more than two years in people with microalbuminuria, and comparing these with data obtained from similar trials in normo-and macroalbuminuric patients. The following aspects are covered: traditional concepts of diabetic nephropathy, methodology, changing treatment
targets of microalbuminuria, the influence of hyperfiltration on AER, the influence of albuminuria on GFR, AER-GFR relationships in microalbuminuric patients with type 1 compared with type 2 diabetes, albuminuric and nonalbuminuric pathways to impaired GFR, and new understanding of albumin handling by the kidney.
