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 (3–9) and type 2 (12–17) diabetes have documented and demonstrated the usefulness of microalbuminuria in intervention studies.
Table 1—
Progression of microalbuminuria to nephropathy in diabetic patients
Footnotes
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Address correspondence to Professor Hans-Henrik Parving, Steno Diabetes Center, Niels Steensensvej 2, DK-2820 Gentofte, Denmark. E-mail: hhp@novonordisk.com.
References
- ↵
Tabaei BP, Al Kassab AS, Ilag LL, Zawacki CM, Herman WH: Does microalbuminuria predict diabetic nephropathy? Diabetes Care 24:1560–1566, 2001
- ↵
Caramori ML, Fioretto P, Mauer M: The need for early predictors of diabetic nephropathy risk. Is albumin excretion rate sufficient? Diabetes 49:1399–1408, 2000
- ↵
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. JAMA 271:275–279, 1994
- ↵
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. Am J Med 99:497–504, 1995
- ↵
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. Diabetes Care 21:104–110, 1998
- ↵
The Euclid Study Group: Randomised placebo-controlled trial of lisinopril in normotensive patients with insulin-dependent diabetes and normoalbuminuria or microalbuminuria. Lancet 349:1787–1792, 1997
- ↵
Mathiesen ER, Hommel E, Giese J, Parving H-H: Efficacy of captopril in postponing nephropathy in normotensive diabetic patients with microalbuminuria. Br Med J 303:81–87, 1991
- ↵
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 24:919–924, 2001
- ↵
The ATLANTIS Study Group: Low-Dose ramipril reduces microalbuminuria in type 1 diabetic patients wihout hypertension. Diabetes Care 23:1823–1829, 2000
- ↵
Mogensen CE: Microalbuminuria predicts clinical proteinuria and early mortality in maturity onset diabetes. N Engl J Med 310:356–360, 1984
- ↵
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 335:1636–1642, 1996
- ↵
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 156:286–289, 1996
-
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 353:617–622, 1999
- ↵
Ahmad J, Siddiqui MA, Ahmad H: Effective postponement of diabetic nephropathy with enalapril in normotensive type 2 diabetic patients with microalbuminuria. Diabetes Care 20:1576–1581, 1997
- ↵
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. Diabetes Care 23:B54–B64, 2000
- ↵
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 355:253–259, 2000
- ↵
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 345:870–878, 2001
- ↵
Parving H-H: Diabetic nephropathy: Prevention and treatment. Kidney Int 60: 2001
