Association between albuminuria and both office and 24 hours ambulatory blood pressure

Abstract

Objective: Albuminuria has been linked more closely with blood pressure (BP) values in ambulatory blood pressure monitoring (ABPM) than with the BP in consultation. Our purpose was to analyse this association. Design and method: Observational, crossectional study in patients with EH. Albuminuria was calculated as the average of 2 determinations (turbidimetry). The office BP was determined as the average of 3 measurements and ABPM was performed with a SPACELAB monitor, mod. 90217. Results: We included a total of 1130 patients (50.3% male) with a mean age of 57 (14) years, 25% with type 2 DM. Office BP values were 147 (19)/81 (12) mm Hg and ABPM 133(15)/80 (10) mm Hg in the daytime and 121 (16)/70 (10) mm Hg in the night time. The mean values of albuminuria and eGFR-EPI-creatinine were 30 (121) mg/g creatinine and 84 (21) ml/min/1.73 m2, respectively. Albuminuria, adjusted for age and sex, was positively correlated with BMI (r = .075, p = 0.038), office SBP (r = .082, p = 0.024), office DBP (r = .073, p = 0.043), daytime SBP (r = .119, p = 0.001) and night time DBP (r = .094, p = 0.010) and negatively for eGFR-EPI-creatinine (r = -.104, p = 0.004). The ratio of night-time/day-time SBP and DBP was not correlated with albuminuria. There were no differences in albuminuria within patients classified as non-dipper vs. dipper neither for the SBP (32 vs. 27 mg./gr., respectively, p = 0.581) nor DBP (34 vs. 27 mg./ g., p = 0.386). In multivariate analysis the only independent determinants of albuminuria were daytime SBP (beta = 1.136, 95% CI .547–1.72, p < 0.0001) and BMI (beta = 1.80, 95% CI .082–3.52, p = 0.069). Conclusions: In our patients with EH, albuminuria was only associated, in addition to BMI, with the values of diurnal SBP in 24 h. Neither the night time BP values nor the pattern of nocturnal dipping showed this association. The 24-hour ABPM may well be a more effective tool than office BP for assessing this cardiovascular risk factor.