Comparison of granulomatosis with polyangiitis clinical features in patients depending of involvement or absence of kidney involvement.

BACKGROUND GPA is a necrotizing inflammation of the small vessels with granulomas. Kidney involvement deteriorated its prognosis. OBJECTIVE Comparison of GPA patients with kidney (KI) and without kidney involvement (nKI). MATERIAL AND METHODS We conducted a cross-sectional study of 50 consecutive adult GPA patients, 25 KI from Nephrology and 25 nKI from Rheumatology Department of Central Clinical Hospital Ministry of Interior in Warsaw. We analyzed clinical features, organ involvement, laboratory, serological, imaging, histopathological data, BVAS, treatment. RESULTS The mean age of KI patients was statistically older then nKI (67.3±9.5 vs 55.1±15.9, p=0.002). Generalized, severe, resistance disease was observed respectively in 92% vs 44%, p<0.001. The number of red blood cells (3.47 vs 4.41T/l, p<0.001), hemoglobin (10.0 vs 12.9g/dl, p<0.001) was lower in KI, higher mean serum creatinine (3.95 vs. 0.89mg/dl, p<0.001), lower GFR (20.1 vs. 79.3, p<0.001), higher CRP (median: 43.4 vs 2.0mg/l, p<0.001), BVAS (16.6±4.4 vs 10.1±6.2, p<0.001), c-ANCA (median: 119.0 vs 15.2CU, p=0.017). Nodules in 28% KI, in 4% nKI (p=0.048) in chest X-ray, infiltration in 43.5% KI, in 15% nKI (p=0.042) in HRCT were observed. Skin granulomas were found in 61.5% nKI vs 18.2% KI, (p=0.047). Renal biopsy revealed in KI patients focal segmental glomerulonephritis in 11.8%, crescentic glomerulonephritis in 17.6%, pauci-immune crescentic glomerulonephritis in 70.6%. CONCLUSIONS In patients with KI more frequently we found generalized, severe, resistant GPA, higher BVAS in comparison in patients without KI. The results of laboratory parameters, were worse in patients with KI. Aggressive immunosuppressive treatment is often used in KI group.