Chronic disease: #22 Does increase in blood pressure predict increase in urinary albumin excretion rate in the first 9 years of type 1 diabetes?

PURPOSE: The prevalence of hypertension and microalbuminuria (MA) has been described for individuals with type 1 diabetes of many years duration, but less is known about the early years of this condition. This study sought to determine the frequency of MA (greater-or-equal, slanted20 mcgs/min), a marker for early diabetic kidney disease, and hypertension in the first 9 years of diabetes, and to determine if changes in blood pressure precede kidney disease. METHODS: This population-based cohort includes 517 predominantly white individuals <29 years of age followed prospectively from diagnosis of type 1 diabetes. An average of four blood pressure and UAE measurements were collected over a 9-year period. Early (the first 5 years of diabetes) and late (6–9 years) frequencies, within-individual means and slopes were determined for blood pressure and urinary albumin variables. Multivariable linear regression was used to compare within individual means and slopes. RESULTS: Early and late mean urinary albumin excretion (UAE) rates were 8.36 and 9.36 mcgs/min, respectively. In years 6–9, 6.9% of individuals had MA, 3.1% had systolic and 6.8% had diastolic blood pressures considered hypertensive according to age and height standardized data. The rate of hypertension in this cohort is similar to the general population as described by the Working Group Report from the National High Blood Pressure Education Program. Early increased diastolic blood pressure (slope) marginally significantly predicted late increased UAE (slope) in males, but not females, after adjustment for age. CONCLUSION: Microalbuminuria and hypertension are infrequent in the first 9 years of diabetes. Microalbuminuria is less frequent than expected. The marginal relationship between blood pressure and UAE in males may provide insight into the greater lifetime risk of overt diabetic renal disease observed in males.