[Modifications of 24-h blood pressure profile associated with reduction of the heart rate variability in type 1 diabetic patients].

Unlabelled: The purpose of this study was to assess the blood pressure modifications in type 1 diabetic patients who present reduction of heart rate variability.

Patients And Methods: This study included 70 type 1 diabetic patients (mean age: 42 +/- 13 years, diabetes duration: 13.2 +/- 9 years. They were free for complications and did not receive other treatment than insulin. Heart rate variability was evaluated using 24-h continuous ECG record spectral analysis. Patients were divided into two groups according to whether log high frequency power was lower (group 1, N=36) or higher (group 2, N=3 4) than 70 patients'mean. Clinical and biological features and 24-h ambulatory blood pressure measurement were compared in both groups.

Results: Patients of group 1 were older than group 2 (47.8 +/- 11.2 vs. 35.7 +/- 12.2 years, p<0.0001) and diabetes duration was higher (16.9 +/- 8.4 vs. 9.4 +/- 8 years, p<0.001). BMI and Hb A1c did not differ from significant in both. Night-time blood pressure was upper in group 1 (SBP: 112 +/- 13 vs. 103 +/- 11 mmHg, p<0.01 and DBP: 66 +/- 8 vs. 60 +/- 7 mmHg, p<0.001). The difference between blood pressures during day and night (DeltaBP) were lower in group 1 than in group 2 (DeltaSBP: 10 +/- 9 vs. 15 +/- 7 mmHg, p<0.02 and DeltaDeltaBP: 9 +/- 7 vs. 12 +/- 5 mmHg, p<0.04). DSBP and DDBP were found to be correlated with log HF power (r=0.356, p<0.003), which could explain 11.8% and 12% of their variance. Urinary albumin excretion rate was higher in group 1 (8 +/- 4 vs. 5 +/- 3 mg/24h, p<0.01).

Conclusion: In type 1 diabetic patients free for complications, reduction in heart rate variability linked to age and diabetes duration is associated with a reduction in nighttime BP fall. These two parameters of autonomic neuropathy could have a pathogenic role in the development of incipient nephropathy.