Prediction of albuminuria by different blood pressure measurement methods in type 1 diabetes: a pilot study

In type 1 diabetes, the risk of nephropathy is strongly influenced by the level of blood pressure (BP). Ambulatory BP (ABP) monitoring has revealed an association between disturbed nocturnal BP drop and albuminuria and suggested a role of BP in microalbuminuria development. This study investigated the relationship between the urinary albumin excretion ratio (AER) and home BP (HBP) compared with ABP and clinical BP (CBP) measurements. A total of 50 adolescents and young adults with type 1 diabetes without hypertension or overt proteinuria (mean age 20 +/- 3.8 (s.d.) years, 21 male) had measurements of CBP (3 visits), HBP (6 days), 24-h ABP and AER (daytime and nighttime in the same 24 h with ABP monitoring). AER of 24 h was correlated with systolic 24-h (r=0.31), daytime (r=0.33) and nighttime ABP (r=0.36), without significant correlation with diastolic ABP, CBP or HBP (systolic or diastolic). Nighttime AER was correlated with 24-h (r=0.39/0.35, systolic/diastolic), daytime (r=0.36/0.32) and nighttime ABP (r=0.44/0.28). HBP was not associated with nighttime AER, but CBP was (diastolic BP only, r=0.41). No significant correlations were found between daytime AER and BP measurements. The nocturnal BP dip was not associated with any BP value. In non-dippers, nighttime AER showed strong correlations with ABP (24-h: r=0.45/0.42, systolic/diastolic; daytime: r=0.46/0.45; nighttime: r=0.49/0.35), HBP (r=0.34/0.31) and CBP (r=0.39/0.47). No such associations were found in dippers (r=0.05-0.10). These preliminary data suggest that in the early stage of diabetes-1, 24-h ABP monitoring seems to be the optimal method of revealing the association between BP and albuminuria, and cannot be replaced by HBP monitoring. Hypertension Research (2009) 32, 680-684; doi:10.1038/hr.2009.82; published online 5 June 2009