MO204: IGA Nephropathy: FACTORS that Influence Renal Survival and Progression to End-Stage Renal Disease

Abstract

BACKGROUND AND AIMS IgA nephropathy (IgAN) is the most common form of primary glomerulonephritis worldwide and an important cause of kidney failure requiring kidney replacement therapy [1]. Given that IgAN has no specific treatment and the options available are often associated with significant side effects, searching for risk factors for disease progression can improve the prognosis determination and, therefore, support the therapeutical approach decision. Our aim was to evaluate factors that lead to poor renal survival and progression to end-stage renal disease (ESRD) in patients with histological diagnose of IgAN. METHOD A retrospective study was conducted including the patients with histological diagnose of IgAN between 2007 and 2019 that maintained regular follow-up in our center. Clinical, analytical and histological data were collected and analyzed. Renal survival was defined by a status free of ESRD and renal function decline lower than 50% over time. ESRD was defined as an estimated glomerular filtration rate (eGFR) <15 mL/min/1.73 m2 or need for chronic dialysis. RESULTS A total of 59 patients were included, 39 males, with a mean age at diagnoses of 42.7 ± 17.4 years and a mean follow-up time of 8.2 ± 3.8 years. The initial mean eGFR was 84 ± 31.4 mL/min/1.73 m2 and 40.7% of patients had hypertension at time of diagnoses. A total of 41 patients (69.5%) were treated with renin–angiotensin–aldosterone system inhibitors and 16 (27.1%) with immunosuppressive agents, 13 with corticosteroids and 3 with corticosteroids and cyclophosphamide. A total of 12 patients (20.3%) showed an impaired renal survival during the follow-up, and 7 (11.9%) progressed to ESRD. We found that time-average proteinuria was significantly higher in patients who presented poor renal survival (1.26 ± 0.89 g/24 h versus 3.21 ± 2.2 g/24 h; P < .001). Also, the proportion of patients reaching ESRD or a 50% reduction of renal function was significantly greater among patients with persistent hematuria during the follow-up than in those who presented resolution of hematuria (28.2% versus 17.9% and 53.8% versus 0%; P = .002). Furthermore, we found that patients who presented on the kidney biopsy a more intense immunofluorescence staining of C3 were more likely to evolve to ESRD or have greater loss of kidney function (p=.001). Other variables, such as male gender, lower eGFR and presence of hypertension at diagnoses, also showed to be related to poor renal survival, although they did not reach statistical significance. The treatment with renin–angiotensin–aldosterone system inhibitors or immunosuppressive agents did not show impact on renal survival. CONCLUSION The grade of proteinuria is a well-established predictor of worse outcomes in patients with IgAN, and its reduction is one of the main objectives in these patients. On the other hand, the role of hematuria in disease progression is still controversial and the relationship between the level of C3 deposition and the long-term prognosis has rarely been reported [1, 2, 3]. With our data, we reinforce the need to integrate all different pathophysiological mechanisms to establish the disease prognosis.