PS-C32-6: ASSOCIATION BETWEEN BLOOD PRESSURE COMPONENTS AND RENAL HISTOLOGIC FINDINGS IN PATIENTS WITH IGA NEPHROPATHY

Abstract

Objective: The diverse histological findings in IgA nephropathy are often evaluated using the Oxford classification for glomerular, tubular/interstitial, and vascular lesions. Patients with IgA nephropathy are prone to hypertension, but the relationship between the histological findings and blood pressure (BP) is not well known. In addition to systolic BP (SBP) and diastolic BP (DBP), mean arterial pressure (MAP) as a steady component and pulse pressure (PP) as a pulsatile component are also important BP components. Therefore, we investigated the detailed relationship between these BP components and renal histological findings. Design and method: Among 340 patients with IgA nephropathy diagnosed by renal biopsy between June 1996 and December 2008, 230 patients aged 15–65 years who were not taking antihypertensive medications other than renin-angiotensin-aldosterone system (RAAS) inhibitors and had serum creatinine levels < 2.0 mg/dL were included in this cross-sectional analysis. Multiple logistic regression analysis was used to examine the association between four BP components and pathological factors. Pathological factors were evaluated using parameters included in the Oxford classification: mesangial hypercellularity (mesangial score > 0.5 or ≦ 0.5), segmental glomerulosclerosis (yes/no), endocapillary hypercellularity (yes/no), global glomerulosclerosis (≦ 13.6% of the total number of glomeruli, which indicates the highest quartile of the total population, or < 13.6%), tubular atrophy/interstitial fibrosis (> 10% of cortical area, or ≦ 10%), cellular/fibrocellular crescents (yes/no), and arteriosclerosis (yes/no). Results: The prevalence of mesangial hypercellularity, segmental glomerulosclerosis, endocapillary hypercellularity, tubular atrophy/interstitial fibrosis, cellular/fibrocellular crescents and arteriosclerosis were 47.8%, 84.8%, 37.4%, 20.9%, 33.9%, and 32.2%, respectively. After adjustment for age, sex, smoking status, alcohol status, and use of RAAS inhibitors, global glomerulosclerosis and tubular atrophy/interstitial fibrosis were significantly associated with DBP, and arteriosclerosis was associated with SBP, DBP, and MAP, whereas mesangial hypercellularity, segmental glomerulosclerosis, endocapillary hypercellularity, and cellular/fibrocellular crescents were not associated with any BP component. The multiple-adjusted odds ratio of global glomerulosclerosis for DBP per 10 mmHg was 1.67 (95% CI 1.09–2.55), and that of tubular atrophy/interstitial fibrosis for DBP per 10 mmHg was 1.66 (95% CI 1.06–2.60). The multiple-adjusted odds ratios of arteriosclerosis were 1.58 (95% CI 1.16–2.15), 1.89 (95% CI 1.26–2.83), and 1.62 (95% CI 1.15–2.29) for SBP, DBP, and MAP per 10 mmHg, respectively. Conclusions: In the cross-sectional study of patients with IgA nephropathy, global glomerulosclerosis, tubular atrophy/interstitial fibrosis, and arteriosclerosis were associated with DBP, and arteriosclerosis was also associated with SBP and MAP. On the other hand, segmental glomerulosclerosis, endocapillary hypercellularity, and cellular/fibrocellular crescents had no association with any BP component.