Nocturnal blood pressure in young patients with insulin-dependent diabetes mellitus: Correlation with cardiac function

Lack of a decline in nocturnal blood pressure is associated with an adverse effect on end organs in adults with insulin-dependent diabetes mellitus (IDDM). The role of the decline in nocturnal blood pressure in young patients with IDDM is not known. We studied 25 white subjects with IDDM (age = 20.8 ± 3.7 years, mean ± SD), 8 of whom were female. The duration of IDDM in these subjects was 12.9 ± 5.4 years (mean ± SD). We determined the values for glycosylated hemoglobin (HgbA1), 24-hour ambulatory blood pressure, diastolic cardiac function (the ratio of peak E wave to peak A wave velocity [E/A] and indexed peak filling rate {PFR/SV} by Doppler echocardiography), and albumin excretion rate. The HgbA1 level was 10.9% ± 1.9% (mean ± SD; normal range = 4.5%-8.5%). The HgbA1 concentration was inversely correlated ( p < 0.005) with the decline in systolic ( r = –0.57) and diastolic ( r = –0.55) nocturnal blood pressure. Diastolic cardiac dysfunction {E/A ratio [ r = 0.42, p < 0.03) and PFR/SV ( r = 0.52, p < 0.01)} correlated with a smaller decrease in nocturnal diastolic blood pressure. An inverse correlation between decline in nocturnal systolic blood pressure and log albumin excretion rate ( r = –0.37, p = 0.07) approached statistical significance. We conclude that poor glycemic control adversely affects nocturnal blood pressure and that the latter may play an important role in cardiac and possibly renal dysfunction in early IDDM. (J Pediatr 1998;133:46-50)