September 2002 - Monitoring nighttime blood pressure is a simple, painless and noninvasive method of identifying patients with type 1 diabetes who are at increased risk for kidney disease, according to a study published in the Sept. 12 issue of The New England Journal of Medicine.
Daniel Batlle, M.D., professor of medicine at The Feinberg School of Medicine at Northwestern University and researchers from Spain showed that in persons with type 1 diabetes, an increase in systolic blood pressure during sleep precedes the development of microalbuminuria -- or a protein called albumin in the urine -- a condition that is predictive of kidney disease.
In their prospective study, the investigators used 24-hour ambulatory blood pressure monitoring in 75 adolescents and young adults with type 1 diabetes who had normal blood pressure and urinary albumin excretion levels at enrollment. Over a follow-up period of five years, 14 of the patients had developed microalbuminuria.
This group also had nighttime systolic blood pressure that was significantly higher than those in study participants with normal urinary albumin levels. By contrast, in those whose blood pressure during sleep decreased normally, the progression from normal albumin excretion to microalbuminuria appeared to be less likely.
Blood pressure has a normal circadian rhythm and varies depending on levels of stress and physical activity.
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"Thus, blood pressure measured randomly at the physician's office cannot fully reflect blood pressure levels around the clock, particularly when it is close to the normal range at earlier stages of diabetes," Batlle said.
The researchers said that an increase in nighttime systolic pressure appears to be the earliest detectable manifestation of altered blood pressure regulation in patients with type 1 diabetes and may provide a good way for choosing or avoiding unnecessary therapies to prevent microalbuminuria and kidney disease in patients with type 1 diabetes.
Source: Northwestern University
