Day-night blood pressure variation in normotensive, normoalbuminuric type I diabetic subjects. Dippers and non-dippers.

OBJECTIVE

To examine day-night blood pressure (BP) variation in normotensive, normoalbuminuric subjects with type I diabetes and to assess the prevalence of an impaired nocturnal BP fall.

RESEARCH DESIGN AND METHODS

Fourteen healthy volunteers and 13 normotensive, normoalbuminuric subjects with type I diabetes were studied with an ambulatory sphygmomanometric device for 24 h.

RESULTS

No significant difference was found between diabetic and control groups with regard to daytime systolic blood pressure (sBP) or diastolic blood pressure (dBP). However, the mean nighttime sBPs (P < 0.01) and dBPs (P = 0.01) were significantly higher in the diabetic group compared with the control group. Furthermore, the night/day ratio for both sBP (P < 0.01) and dBP (P < 0.01) was significantly higher in the diabetic group. Approximately half of the diabetic subjects studied were non-dippers when defined either by a nocturnal fall in sBP/dBP of < 10/5 mmHg (5/13 vs. 0/14, P < 0.05: diabetic group vs. control group) or a day to night fall in either sBP (7/13 vs. 2/14, P < 0.05) or dBP (6/13 vs. 0/14, P < 0.01) of < 10%.

CONCLUSIONS

Ambulatory BP may reveal impaired nocturnal BP fall in normotensive, normoalbuminuric subjects with type I diabetes. These subjects may be at greater risk of certain complications as a consequence of an increased BP burden.