Increased nocturnal blood pressure variability is associated with renal arteriolar hyalinosis in normotensive patients with IgA nephropathy

Abnormal blood pressure (BP) variability (BPV), occurring as beat-to-beat, 24 h, and day-to-day fluctuations, is related to target organ damage. However, the associations between abnormal BPV and renal structural changes have not been clearly investigated. We evaluated the day time and night time BP s.d. and average real variability (ARV), which reflected short-term BPV, the night time to day time (N/D) ratio of systolic BP (SBP), and the 7-day BPV, in 29 normotensive IgA nephropathy (IgAN) patients. We further compared the results with renal structural changes. The degree of arteriosclerosis was positively correlated with age, s.d. of night time SBP and the N/D ratio of SBP, and was negatively correlated with the estimated glomerular filtration rate (eGFR). The degree of arteriolar hyalinosis was positively correlated with age, night time SBP, s.d. of day time and night time SBP, day time and night time ARV, the N/D ratio of SBP and 7-day SBP, and was negatively correlated with the eGFR. A multiple linear regression analysis revealed that the level of arteriolar hyalinosis, but not arteriosclerosis, was associated with the s.d. of night time SBP (β=0.63, P<0.01) or night time ARV (β=0.61, P<0.01) after adjustment for age, sex, body mass index, the eGFR and night time SBP. Multiple linear regression analyses indicated no significant correlation between the degree of arteriolar hyalinosis and the N/D ratio of SBP or 7-day SBP s.d. or between the degree of arteriosclerosis and any of the BPV parameters. In conclusion, short-term night time BPV was found to be associated with arteriolar hyalinosis in normotensive IgAN patients.