Microalbuminuria in patients with NIDDM: An overview

The introduction of the concept of microalbuminuria, i.e., elevated but clinically undetectable urinary albumin excretion, has unveiled new and exciting information with profound clinical implications for the care of diabetic patients. For largely historical reasons, however, progress in this area has been confined predominantly to patients with IDDM. Important issues such as definition, natural history, and clinical significance of microalbuminuria as well as merits of therapeutic intervention have been extensively addressed in the case of patients with IDDM. Far less recognition and dedication, however, has been awarded to the study of microalbuminuria in NIDDM until very recently. Emerging new facts are slowly changing the scene, gradually restoring the spotlight in favor of NIDDM. To begin with, NIDDM is ten times more common than IDDM in the community at large and its toll in terms of morbidity and mortality is disturbing. Thus, while the proportion of NIDDM patients who will ultimately develop end-stage renal failure is much smaller than that for patients with IDDM, the sheer numerical superiority of NIDDM ensures that the human and economic burden of diabetic end-stage renal disease is at least equally distributed between the two types of diabetes. Secondly, it has been demonstrated in numerous studies over the past decade that microalbuminuria is not only an independent predictor of progressive renal disease (as has been the case in patients with IDDM) but also an important marker of atherosclerotic disease and premature death in people with NIDDM. Indeed, the development of microalbuminuria in patients with NIDDM is closely related to abnormalities of hemostasis, coagulation, and glucose and lipid metabolism. Microalbuminuria may precede and even predict later onset of NIDDM. Finally, the recent revelations that microalbuminuria per se may represent an independent manifestation of the cardiometabolic disorder syndrome X have added a new dimension to the study of microalbuminuria in NIDDM. Thus, the clinical importance of microalbuminuria in patients with NIDDM cannot be overstated, and greater awareness of its significance by clinicians and health care providers should be actively reinforced. In this article, therefore, I will review the topic of microalbuminuria as it pertains to NIDDM, placing emphasis on past difficulties, recent developments, and the rationale and limitations of medical intervention.