PURPOSE

To examine the characteristics of ambulatory blood pressure (ABP) including blood pressure variability (BPV) and its association with albuminuria in type 1 diabetic (T1D) children and to identify potential predictors of high-normal albuminuria and microalbuminuria.

METHODS

ABP monitoring was performed in 201 T1D children and adolescents (mean age, 14.7±3.8 years) with T1D duration over 1 year. The level of albuminuria was assessed as the albumin/creatinine ratio (ACR) and patients were further classified as low-normal, high-normal or microalbuminuria.

RESULTS

Fifteen T1D children (7.5%) were hypertensive using office blood pressure (BP) and 10 (5%) according to ABP. T1D subjects had elevated 24-hour systolic BP (SBP) and diastolic BP (DBP) (+0.2 and + 0.3 standard deviation score [SDS]) and nighttime SBP and DBP (+0.6 and +0.8 SDS) compared to reference values. Patients with microalbuminuria had significantly higher 24-hour, daytime and nighttime DBP compared to normoalbuminuric subjects. There was a high percentage of nondippers (74.1%). Nighttime diastolic BPV was significantly higher in subjects with high-normal compared to low-normal albuminuria (p=0.01). A weak correlation was found between ACR and daytime DBP SDS (r=0.29, p<0.001 and nighttime DBP SDS (r=0.21, p=0.003). Age and nighttime diastolic BPV were predictors of high-normal albuminuria while nighttime DBP was a strong predictor for microalbuminuria.

CONCLUSION

T1D children have impaired BP regulation although most of them do not fulfill the criteria for sustained hypertension. There is an association between diastolic ABP and diastolic BPV with rising levels of albuminuria pointing to a clear connection between BP and incipient diabetic nephropathy.