Nondipping and its relation to glomerulopathy and hyperfiltration in adolescents with type 1 diabetes.
OBJECTIVE
To determine whether there is a relation between dipping/nondipping status and end-organ damage (measured as renal glomerulopathy) and long-term renal function in order to predict the development of nephropathy in normoalbuminuric patients with type 1 diabetes.


METHODS
Analysis of renal biopsy and ambulatory blood pressure measurements was done in relation to renal function tests performed during a 10-year period. Forty unselected patients (16 girls), with a mean age of 17.7 years and a mean duration of 10.7 years, were studied. The renal biopsies were examined by electron microscopy. Ambulatory blood pressure was monitored (Space Labs 90 207). Systolic nondippers were defined as a <7%, diastolic nondippers as a <14%, and mean arterial blood pressure (MAP) nondippers as a <12% fall in blood pressure during the night. Renal function was evaluated every other year by clearances of inulin (glomerular filtration rate [GFR]) and para-amino hippurate (effective renal plasma flow [ERPF]), and filtration fraction (GFR/ERPF) was calculated. Overnight urinary albumin excretion rate and long-term mean HbA(1c) were measured.


RESULTS
MAP (27% of the patients) and diastolic nondippers (12%) had a significantly thicker basement membrane; larger mesangial matrix volume fraction; and higher long-term GFR, nighttime heart rate, and mean HbA(1c) than dippers.


CONCLUSIONS
Nondipping status was related to more renal morphological changes and long-term hyperfiltration in normoalbuminuric adolescents and young adults, despite a short duration of type 1 diabetes. Nondipping status may be an early predictor of later nephropathy.
Torbjörnsdotter
Torun B
TB
Department of Pediatrics, Karolinska Institutet, Huddinge University Hospital, Stockholm, Sweden. torun.torbjornsdotter@klinvet.ki.se
Jaremko
Georg A
GA
Berg
Ulla B
UB
D000293:Adolescent; D001706:Biopsy; D001794:Blood Pressure; D018660:Blood Pressure Monitoring, Ambulatory; D002940:Circadian Rhythm; D003922:Diabetes Mellitus, Type 1 / Q000503:physiopathology*; D003929:Diabetic Neuropathies / Q000473:pathology / Q000503:physiopathology*; D005260:Female; D005919:Glomerular Filtration Rate / Q000502:physiology*; D006339:Heart Rate; D006801:Humans; D007668:Kidney / Q000473:pathology / Q000648:ultrastructure; D007677:Kidney Function Tests; D008297:Male; D012044:Regression Analysis