[Role of nocturnal hypertension in the deterioration of diabetic nephropathy].

UNLABELLED

Nocturnal hypertension (HTA), even a relative one, consequence of the change of the circadian pattern of blood pressure, may increase the whole day blood pressure in diabetic patients.

MATERIALS AND METHODS

blood pressure has been measured every 15 minutes for 24 hours in 101 diabetic patients (43 insulin-dependent: type 1, 58 non insulin-dependent: type 2) by ambulatory blood pressure monitoring. 39 of them are hypertensive patients. Among these 101 patients, 19 have a nocturnal relative HTA corresponding in a lack or a negative difference between the diurn and the nocturn systolic or diastolic pressure (Group 1). The Group 2 is constituted by the 82 other patients; 24 hour-microalbuminuria was assayed by immunoturbidimetry for two days on end.

RESULTS

patients of Group 1 were significantly older (p less than 0.01) than in the Group 2 (61 +/- 9 years vs 54 +/- 13 years). There was no significant change between the two Groups concerning the kind of diabetes (type 1 or type 2), the glycosylated hemoglobin and the frequency of degenerative complications. Microalbuminuria was significantly higher (p less than 0.01) in Group 1 (72 +/- 104 mg/24 h) than in Group 2 (20 +/- 30 mg/24 h). Both nervous dysautonomic cardiac failure and HTA treated were significantly higher in Group 1 than in Group 2, respectively (14/19 vs 28/82; p less than 0.01) and (15/19 vs 24/82; p less than 0.001). The causal blood pressure measurement was similar in the two Groups, but the whole day ambulatory blood pressure monitoring revealed a significant increase of the average of systolic (Group 1: 133 +/- 14 mmHg vs Group 2: 119 +/- 12 mmHg; p less than 0.001) and diastolic (Group 1: 81 +/- 12 mmHg vs Group 2: 75 +/- 8 mmHg; p less than 0.01) blood pressure during 24 hours.

COMMENTS

the causal blood pressure measurement fails to appreciate the increase of the whole day blood pressure consequent to the suppression of nocturnal hypotension and sometimes to the occurrence of real nocturnal hypertension. This observation is probably in relation with the nervous dysautonomic cardiac failure and is associated with an increase of the microalbuminuria (patients with microalbuminuria greater than 30 mg/24 h--Group 1: 9/19 vs Group 2: 17/82; p less than 0.05). This situation can lead to an aggravation of degenerative complications. Such results should urge practitioners to assess the circadian pattern of blood pressure in diabetic patients more accurately.