968 Impact of the presence of acute kidney injury at the time of renal biopsy on long-term prognosis of IgA nephropathy

Abstract Background and Aims IgA nephropathy is the most common primary glomerular disease and an important cause of end-stage renal disease. Factors such as decreased renal function, persistent proteinuria, hypertension, and older age predict a poor prognosis in IgA nephropathy. Current international prediction tools for IgA nephropathy determine prognosis based on renal function using estimated glomerular filtration rate (eGFR) at the time of kidney biopsy. However, we observed differences in prognosis between patients with and without concurrent acute kidney injury (AKI) at the time of kidney biopsy. Therefore, we aimed to investigate whether renal function at the time of renal biopsy is a suitable indicator for assessing the long-term prognosis of patients with IgA nephropathy with AKI. Method We retrospectively analyzed a total of 185 patients who were diagnosed with IgA nephropathy between 2009 and 2016 at the Gyeongsang National University Hospital. Clinical data, including pathological, demographic, and laboratory findings of patients, were used. We divided the patients into two groups based on the progression rate of kidney function per year, ‘Progression’ or ‘Non-progression group’. AKI was defined according to the KDIGO Clinical Practice Guidelines. Results Among a total of 185 patients, 113 showed a sustained decline in eGFR of more than 1 ml/min/1.73 m2 per year. The mean eGFR level of the non-progression group was significantly lower than that of the progression group (p = 0.027). The percentage of patients with AKI in the non-progression group was 25%, which was higher than that in the progression group (p < 0.001). The two groups had no significant differences in comorbid disease, medications at kidney biopsy, and treatment. In sub-analysis, the mean eGFR at kidney biopsy was significantly lower than that in the non-AKI group (p < 0.001). The mean estimated risk, calculated by the international prediction tool, was significantly lower in the AKI group. On the other hand, the mean rate of actual GFR decline per year was higher in the non-AKI group (p < 0.001). Conclusion We confirmed a discrepancy between the predicted prognosis and the actual decline in GFR, particularly in the AKI group. We found that AKI at the time of renal biopsy was a good long-term prognostic factor. There is a need to conduct further research to confirm whether this is due to early detection of AKI and early active treatment.