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IgAN is the most common cause of primary glomerulonephritis. Generally, 30% of IgAN patients progress slowly to ESKD. Disease progression and prognosis of IgAN are mainly associated with clinical factors such as proteinuria, serum creatinine and pathological features including glomerular sclerosis, interstitial fibrosis and tubular atrophy. Many clinicians should make effort to minimize progression of IgAN through identifying risk factors associated with the progression of IgAN. Therefore, it is important for nephrologists to take a clinical approach through correlation analysis of various factors, including clinical or pathological factors of IgAN. We evaluated the relationship between various clinical or pathological factors in patients with IgAN during recent 10 years.
Total 112 patients were diagnosed with IgAN by the kidney biopsy for recent 10 years were retrospectively analyzed. The enrolled patients were monitored about 2 years. The IgAN was confirmed if IgA staining of ≥ 1+ in mesangium was shown on immunofluorescence (IF) microscopic findings, and patients suspected of having secondary glomerulonephritis including lupus nephritis and infectious glomerulonephritis were excluded. Comparative analysis with baseline serum creatinine, serum BUN, various histological features (global sclerosis (GS), segmental sclerosis (SS), interstitial fibrosis and tubular atrophy (IF and TA), foot process effacement (FPE), crescent, mesangial proliferation, endocapillary proliferation, serum C3 and C4, Anti neutrophil antibody, urine protein-creatinine ratio (UPCR, g/g), urine albumin-creatinine ratio (UACR, g/g), serum creatinine after 1 year and 2 years and baseline and 1, 2 year estimated glomerular filtration rate (eGFR) (CKD-EPI and MDRD). Clinical factors associated with renal death for recent 10 years were also analyzed. We used categorical principal component analysis and linear discriminant analysis to perform weight correlation analysis of the various factors.
The various risk factors of IgAN patients showed a significant relevance. Especially, baseline serum creatinine and BUN showed deeply positive correlation with specific histologic factors (GS (%), SS (%), and degree of IF and TA, respectively). Baseline UPCR and UACR showed stronger positive correlation with several factors such as serum C3, C4, diabetes, age and degree of endocapillary proliferation. In addition, chronic pathological features, such as GS, SS and IF and TA, and mesangial proliferation and FPE showed completely opposite correlations in pathological features of IgAN patients. (Fig. 1A) Finally, total 13 patients initiated renal replacement therapy during follow-up period. In our study, the factors such as GS (%), baseline serum creatinine, diabetes, UPCR and UACR showed deeply positive correlation with renal death (ESKD). On the other hand, several factors such as endocapillary proliferation, mesangial proliferation and degree of FPE, serum C3 level and estimated GFR (MDRD or CKD-EPI) showed deeply negative correlation with renal death (ESKD). (Fig. 1B)
Conclusions
GS and serum creatinine including UPCR or UACR can be an important risk factors associated with renal death, and the FPE and mesangial proliferation having negative correlation with chronic pathological factors including GS may be good indicators.