Glomerular hyperfiltration is associated with blood pressure abnormalities in normotensive normoalbuminuric IDDM patients.
OBJECTIVE
To analyze the blood pressure patterns in normoalbuminuric IDDM patients with glomerular hyperfiltration.


METHODS
A controlled cross-sectional study of 38 normotensive normoalbuminuric (urinary albumin excretion rate < 20 micrograms/min) IDDM patients (18 hyperfiltering [glomerular filtration rate > 134 ml.min-1 1.73 m-2] and 20 normofiltering) and 20 normal individuals matched for age, sex, and BMI was performed. The 24-h ambulatory blood pressure was monitored using an auscultatory technique (Pressurometer IV, Del Mar Avionics), the glomerular filtration rate was measured by 51Cr-labeled EDTA method, extracellular volume by the distribution volume of 51Cr-labeled EDTA, and the 24-h urinary albumin excretion rate by radioimmunoassay.


RESULTS
Mean nocturnal diastolic blood pressure was higher in hyperfiltering IDDM patients (70.4 +/- mmHg), when compared with the control group (65.1 +/- 5.3 mmHg, P = 0.04). Diastolic blood pressure night:day ratio was higher in hyperfiltering IDDM patients (92.0 +/- 8.6%), when compared with normofiltering IDDM patients (85.9 +/- 4.8%) and control subjects (87.0 +/- 6.8%, P = 0.02). In IDDM patients, the glomerular filtration rate significantly correlated with the diastolic blood pressure night:day ratio (r = 0.5, P = 0.002), extracellular volume (r = 0.04, P = 0.002), and HbA1 (r = 0.3, P = 0.03). In stepwise multiple regression analysis, factors associated with glomerular filtration rate were diastolic blood pressure night:day ratio, extracellular volume, and HbA1 (adjusted r2 = 0.27, P = 0.003).


CONCLUSIONS
Glomerular hyperfiltration is associated with higher nocturnal diastolic blood pressure and with a blunted nocturnal decrease in diastolic blood pressure levels in normotensive and normoalbuminuric IDDM patients.
Pecis
M
M
Endocrine Unit, Hospital de Clínicas de Porto Alegre, Federal University of Rio Grande do Sul, Porto Alegre, Brazil.
Azevedo
M J
MJ
Gross
J L
JL
D000293:Adolescent; D000328:Adult; D000419:Albuminuria / Q000652:urine*; D001794:Blood Pressure / Q000502:physiology*; D018660:Blood Pressure Monitoring, Ambulatory; D003430:Cross-Sectional Studies; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000503:physiopathology* / Q000652:urine; D005260:Female; D005919:Glomerular Filtration Rate / Q000502:physiology*; D006442:Glycated Hemoglobin / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D012044:Regression Analysis; D012189:Retrospective Studies
D006442:Glycated Hemoglobin