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

Introduction: Limited and conflicting data are available about the association between short-term blood pressure (BP) variability and urinary albumin excretion rate (uAER). Aim: To analyse the relationships between microalbuminuria, defined as an uAER between 20 and 200 lg/min, and short-term BP variability, assessed as average real variability (ARV), weighted standard deviation (SD) of 24-h BP, and as SD of daytime and nighttime BP. Methods: The study population consisted of 316 untreated essential hypertensive patients with normal estimated glomerular filtration rate ([60 ml/min/1.73m2), which underwent 24-h ambulatory BP monitoring and 24-h uAER determination. Results: Microalbuminuria was detected in 83 (26 %) patients. ARV of 24-h systolic BP (SBP) was significantly higher in patients with microalbuminuria [9.9 (8.6\u201311.1) mmHg] when compared to those without it [9.1 (8\u201310.2) 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 short-term BPV, only ARV of 24-h SBP (r = 0.17; p = 0.003) and ARV of 24-h DBP (r = 0.13; p = 0.03) were significantly related to (Log) uAER, whereas the relationships of uAER with SD of daytime SBP and with weighted SD of 24-h SBP did not reach the statistical significance (respectively, r = 0.095 and r = 0.085).The correlation of uAER with ARV of 24-h SBP, but not that with ARV of 24-h DBP, remained significant even after adjustment for average 24-h SBP. This association remained significant (b = 0.14; 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 24-h SBP, is independently associated with microalbuminuria