SHORT-TERM VARIABILITY OF 24H SYSTOLIC BLOOD PRESSURE IS ASSOCIATED WITH MICROALBUMINURIA IN PATIENTS WITH PRIMARY HYPERTENSION

Abstract

Objective: Limited and conflicting data are available about the association between shortterm blood pressure (BP) variability and urinary albumin excretion rate (uAER). The objective of our study was to analyze the relationships between microalbuminuria, defined as an uAER between 20 and 200mg/ min, and shortterm BP variability, assessed as average real variability (ARV), weighted standard deviation (SD) of 24h BP, and as SD of daytime and nighttime BP. Design and method: The study population consisted of 315 untreated essential hypertensives with normal estimated glomerular filtration rate (> 60ml/min/1.73 m2), which underwent 24h ambulatory BP monitoring and 24h uAER determination. Results: Microalbuminuriawas detected in 82 (26%) patients.ARVof 24h systolic BP (SBP)was significantly higher in patients with mcroalbuminuria [9.8 (8.5–11.1) mmHg] when compared to those without it [9.1 (8–10.2) mmHg; p = 0.007]. This difference held (p = 0.026) after adjustment for age, mean levels of BP and other potential confounders by ANCOVA. The correlation analysis disclosed that, among the indices of shortterm BPV, only ARV of 24h SBP (r = 0.169; p = 0.003) and ARV of 24h DBP (r = 0.125; p = 0.026) were significantly related to (Log) uAER, whereas the relationships of uAER with SD of daytime SBP and with weighted SD of 24h SBP did not reach the statistical significance (respectively, r = 0.095 and r = 0.085). The correlation of uAER with ARV of 24h SBP, but not that with ARV of 24h DBP, remained significant even after adjustment for average 24 –h SBP (figure). This association remained significant (b = 0.15; p = 0.01), also taking into account the effect of age, gender, diabetes, serum uric acid, triglycerides, eGFR in multiple regression analyses. All the other indices of shortterm BP variability tested were not independently associated with microalbuminuria. Conclusions: Our results seem to suggest that in essential hypertension, short-term BP variability, only when estimated by ARV of 24h SBP, is independently associated with microalbuminuria.