Nondipping and Its Relation to Glomerulopathy and Hyperfiltration in Adolescents With Type 1 Diabetes
- Torun B. Torbjörnsdotter, MD1,
- Georg A. Jaremko, MD, PHD2 and
- Ulla B. Berg, MD, PHD1
- 1Department of Pediatrics, Karolinska Institutet, Huddinge University Hospital, Stockholm, Sweden
- 2Department of Pathology, Karolinska Institutet, Karolinska Hospital, Stockholm, Sweden
- Address correspondence and reprint requests to T. Torbjörnsdotter, MD, Department of Pediatrics, Karolinska Institutet, Huddinge University Hospital, S-14186 Stockholm, Sweden. E-mail: torun.torbjornsdotter{at}klinvet.ki.se
Abstract
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.
RESEARCH DESIGN AND 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 HbA1c 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 HbA1c 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.
- BMT, basement membrane thickness
- ERPF, effective renal plasma flow
- GFR, glomerular filtration rate
- MAP, mean arterial blood pressure
- UAE, urinary albumin excretion rate
Footnotes
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- Accepted November 3, 2003.
- Received June 18, 2003.
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