Clinical and pathological significance of circadian blood pressure rhythm change in IgA nephropathy patients with hypertension / 中华肾脏病杂志

ABSTRACT

Objective To investigate whether the clinical and pathological injury of kidney in IgA nephropathy (IgAN) patients with hypertension is associated with circadian blood pressure rhythm change, particularly with elevated nocturnal blood pressure (BP). Methods This study was a retrospective cross-sectional study. Clinic and renal histopathological injury data were obtained from 83 IgAN patients with hypertension. First, 24 h ambulatory BP monitoring (ABPM) data were analyzed. Second, all these IgAN patients were divided into two groups, elevated nocturnal BP group and nocturnal normotensive BP group, and the clinical and pathological differences between this two groups were analyzed. Third, logistic regression analysis was used to analyze the influencing factors of renal tubulointerstitial injury in IgAN patients with hypertension. At last, all these IgAN patients were divided into two groups according to the level of estimated glomerular filtration rate (eGFR), group of patients with eGFR≥60 ml·min-1·(1.73 m2)-1 and the other group with eGFR<60 ml·min-1·(1.73 m2)-1, and the 24 h ABPM data were compared. Results (1) The proportion of non-dipper circadian rhythm of BP in IgAN patients with hypertension was 79.5％. (2) Compared with nocturnal normotensive BP group, patients in elevated nocturnal BP group had significantly higher levels of 24-hour urinary protein quantity and blood uric acid (both P<0.05), and lower eGFR and urine osmotic pressure clinically (both P<0.05). Index of interstitial fibrosis and tubular atrophy was significantly higher in nocturnal normotensive BP group (P<0.05), while the proportion of glomerular ischemia lesion was not significantly different between two groups. (3) Multivariate logistic regression analysis showed that elevated nocturnal BP was an independent risk factor for severe tubulointerstitial injury of IgAN (OR=1.113, 95％CI 1.038-1.192, P=0.002). (4) Compared with the group of eGFR≥60 ml·min-1·(1.73 m2)-1, 24-hour systolic blood pressure (SBP) and diastolic blood pressure (DBP), daytime SBP and DBP, nocturnal SBP and DBP were significantly higher in group of eGFR<60 ml·min-1·(1.73 m2)-1 (all P<0.05). Conclusion The proportion of non-dipper circadian rhythm of BP in IgAN patients with hypertension is as high as 79.5％. Elevated nocturnal BP is associated with the severity of renal damage, and elevated nocturnal BP is an independent risk factor for severe tubulointerstitial injury in IgAN patients with hypertension. Therefore, 24 h ABPM should be emphasized, and elevated nocturnal BP should be well controlled to slow the progression of IgAN.