Tabaei et al. (1) conclude that “Microalbuminuria may not be as sensitive and specific a predictor of diabetic nephropathy as previously suggested. Other markers of risk for diabetic nephropathy are needed for optimal clinical management.”

This conclusion is based on a 7-year follow-up study of nine (eight women) normotensive type 1 diabetic patients with microalbuminuria and seven middle-aged normotensive type 2 diabetic patients (mainly women) with microalbuminuria. Their conclusions and proposals should be interpreted with great caution because numerous flaws are at hand: 1) a subset of only 32% of the original cohort was investigated, giving rise to many different kinds of biases as demonstrated, e.g., in relation to the included patient population; 2) the generally accepted criteria for microalbuminuria was not fulfilled, neither at baseline nor at the end of the study; 3) values for urinary albumin excretion rate or albumin/creatinine ratio were not presented; 4) the results dealing with progression are presented without any confidence interval, and because the number of patients was extremely small, the confidence interval would be extremely wide; 5) six of seven type 2 diabetic patients and two of nine type 1 diabetic patients received ACE inhibitors at the end of the follow-up; 6) no information of relevant treatment during the follow-up was presented; and 7) the authors have selected references that suit their purpose, including a review article (2) that disregarded all studies in microalbuminuric type 1 and type 2 diabetic patients lasting <5 years.

To compensate for this lack of a balanced view, we have included Table 1, which deals with the outcome of microalbuminuria in type 1 and type 2 diabetic patients. It is quite apparent from the table that the study by Tabaei et al. (1) is the smallest ever reported in the literature.

In conclusion, microalbuminuria is the best documented predictor of high risk for development of diabetic nephropathy in both type 1 and type 2 diabetes, and numerous trials in type 1 (39) and type 2 (1217) diabetes have documented and demonstrated the usefulness of microalbuminuria in intervention studies.

1
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Viberti GC, Mogensen CE, Groop L, Pauls JF, the European Microalbuminuria Captopril Study Group: Effect of Captopril on progression to clinical proteinuria in patients with insulin-dependent diabetes mellitus and microalbuminuria.
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4
Laffel LM, McGill JB, Gans DJ: The beneficial effect of angiotensin-converting enzyme inhibition with captopril on diabetic nephropathy in normotensive IDDM patients with microalbuminuria: the North American Microalbuminuria Study Group.
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5
Crepaldi G, Carta Q, Deferrari G, Mangili R, Navalesi R, Santeusanio F, Spalluto A, Vanasia A, Vila GM, Nosadini R: Effects of lisinopril and nifedipine on the progression of overt albuminuria in IDDM patients with incipient nephropathy and normal blood pressure.
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6
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7
Mathiesen ER, Hommel E, Giese J, Parving H-H: Efficacy of captopril in postponing nephropathy in normotensive diabetic patients with microalbuminuria.
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8
Bojestig M, Karlberg BE, Lindstrom T, Nystrom FH: Reduction of ACE activity is insufficient to decrease microalbuminuria in normotensive patients with type 1 diabetes.
Diabetes Care
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919
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9
The ATLANTIS Study Group: Low-Dose ramipril reduces microalbuminuria in type 1 diabetic patients wihout hypertension.
Diabetes Care
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1823
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10
Mogensen CE: Microalbuminuria predicts clinical proteinuria and early mortality in maturity onset diabetes.
N Engl J Med
310
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356
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11
Nelson RG, Bennett PH, Beck GJ, Tan M, Knowler WC, Mitch WE, Hirschman GH, Myers BD: Development and progression of renal disease in Pima Indians with non-insulin-dependent diabetes mellitus.
N Engl J Med
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12
Ravid M, Lang R, Rachmani R, Lishner M: Long-term renoprotective effect of angiotensin-converting enzyme inhibition in non-insulin-dependent diabetes mellitus.
Arch Intern Med
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13
Gæde P, Vedel P, Parving H-H, Pedersen O: Intensified multifactorial intervention in patients with type 2 diabetes mellitus and microalbuminuria: the Steno type 2 randomised study.
Lancet
353
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14
Ahmad J, Siddiqui MA, Ahmad H: Effective postponement of diabetic nephropathy with enalapril in normotensive type 2 diabetic patients with microalbuminuria.
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15
Estacio RO, Jeffers BW, Gifford N, Schrier RW: Effect of blood pressure control on diabetic microvascular complications in patients with hypertension and type 2 diabetes.
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16
Heart Outcomes Prevention Evaluation (HOPE) Study Investigators: Effects of ramipril on cardiovascular and microvascular outcomes in people with diabetes mellitus: results of the HOPE study and MICRO-HOPE substudy.
Lancet
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17
Parving H-H, Lehnert H, Bröchner-Mortensen J, Gomis R, Andersen S, Arner P: The effect of irbesartan on the development of diabetic nephropathy in patients with type 2 diabetes.
N Engl J Med
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18
Parving H-H: Diabetic nephropathy: Prevention and treatment.
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2001

Address correspondence to Professor Hans-Henrik Parving, Steno Diabetes Center, Niels Steensensvej 2, DK-2820 Gentofte, Denmark. E-mail: hhp@novonordisk.com.