Diabetes Care, Vol 22, Issue 7 1151-1157, Copyright © 1999 by American Diabetes Association
Circadian blood pressure during the early course of type 1 diabetes. Analysis of 1,011 ambulatory blood pressure recordings in 354 adolescents and young adults
RW Holl, M Pavlovic, E Heinze and A Thon
Department of Pediatrics, University of Ulm, Germany. reinhard.w.holl@paediat.med.uni-giessen.de
OBJECTIVE: Little information is available on the early course of
hypertension in type 1 diabetes. The aim of our study, therefore, was to
document circadian blood pressure profiles in patients with a diabetes
duration of up to 20 years and relate daytime and nighttime blood pressure
to duration of diabetes, BMI, insulin therapy, and HbA1c. RESEARCH DESIGN
AND METHODS: Ambulatory profiles of 24-h blood pressure were recorded in
354 pediatric patients with type 1 diabetes (age 14.6 +/- 4.2 years,
duration of diabetes 5.6 +/- 5.0 years, follow-up for up to 9 years). A
total of 1,011 profiles were available for analysis from patients not
receiving antihypertensive medication. RESULTS: Although daytime mean
systolic pressure was significantly elevated in diabetic subjects (+3.1
mmHg; P < 0.0001), daytime diastolic pressure was not different from
from the height- and sex-adjusted normal range (+0.1 mmHg, NS). In
contrast, both systolic and diastolic nighttime values were clearly
elevated (+7.2 and +4.2 mmHg; P < 0.0001), and nocturnal dipping was
reduced (P < 0.0001). Systolic blood pressure was related to overweight
in all patients, while diastolic blood pressure was related to metabolic
control in young adults. Blood pressure variability was significantly lower
in girls compared with boys (P < 0.01). During follow-up, no increase of
blood pressure was noted; however, diastolic nocturnal dipping decreased
significantly (P < 0.03). Mean daytime blood pressure was significantly
related to office blood pressure (r = +0.54 for systolic and r = +0.40 for
diastolic pressure); however, hypertension was confirmed by ambulatory
blood pressure measurement in only 32% of patients with elevated office
blood pressure. CONCLUSIONS: During the early course of type 1 diabetes,
daytime blood pressure is higher compared with that of healthy control
subjects. The elevation of nocturnal values is even more pronounced and
nocturnal dipping is reduced. The frequency of white-coat hypertension is
high among adolescents with diabetes, and ambulatory blood pressure
monitoring avoids unnecessary antihypertensive treatment.