Background: Central blood pressure (cBP) predicts cardiovascular events. Regarding subclinical organ damage, the relationship between urinary albumin excretion (UAE) and cBP is rather unknown.
Objective: We aimed to determine whether cBP is related to UAE, and if this relationship is stronger than that observed with peripheral blood pressure (pBP).
Methods: Three hundred and twenty-four hypertensives (61% men, aged 65 ± 10 years) with insulin-resistance (77% diabetics; 23% nondiabetics with metabolic syndrome) were studied. Office pBP and cBP (radial applanation tonometry) were determined. UAE (albumin/creatinine) was averaged from three first-morning-void urine samples. Differences between patients with/without microalbuminuria, and the relationship between UAE and both pBP and cBP were analyzed. The strength of such relationship (cBP vs. pBP) was compared using a noninferiority test.
Results: Microalbuminuria was detected in 25% of all patients. After age-adjustment and sex-adjustment, both central and peripheral SBP and pulse pressure (PP) (mmHg) were higher in microalbuminurics than in normoalbuminurics [central SBP (cSBP): 130 ± 20 vs. 124 ± 19; peripheral (pSBP): 147 ± 22 vs. 139 ± 20; central pulse pressure (cPP): 52 ± 15 vs. 47 ± 14; peripheral pulse pressure (pPP): 67 ± 16 vs. 62 ± 16, P < 0.05 for all]. Partial correlation coefficients (age-adjusted and sex-adjusted) between blood pressure (BP) and UAE were 0.175 for cSBP, 0.143 for pSBP, 0.124 for cPP (P < 0.05 for all), and 0.092 for pPP (P = 0.117). Neither cBP nor pBP were superior to each other in their association with UAE or with microalbuminuria. Comparisons between cBP and pBP by means of noninferiority tests revealed no differences in the magnitude of correlation coefficients (P = 0.265 for SBP; P = 0.212 for PP), or differences in means between patients with/without microalbuminuria (P = 0.327 for SBP; P = 0.054 for PP).
Conclusion: Although cBP is related with UAE, this relationship is not superior to that of office peripheral BP.