GJ WILSON1,2, A KARK1,2, L FRANCIS3, WE HOY2,4, HG HEALY1,2, A MALLETT1,2,4
1Department of Renal Medicine, Royal Brisbane and Women’s Hospital, Herston, Queensland; 2CKD.QLD & NHMRC CKD.CRE, University of Queensland, Herston, Queensland; 3Department of Pathology, Royal Brisbane and Women’s Hospital, Herston, Queensland; 4Centre for Chronic Disease, University of Queensland, Herston, Queensland
Aim: To determine the rates, causes and characteristics of patients with AIN in an Australian single centre.
Background: The Australian Institute of Health and Welfare’s (AIHW) first report into acute kidney injury demonstrated a significant increase in the incidence of acute tubulo-interstitial nephritis, the ICD-10 code representing both AIN and pyelonephritis, in women aged under 55 years. The incidence of AIN is increasing worldwide and an increased incidence of AIN among younger Australian women may be contributing to this trend.
Methods: Patients who underwent a renal biopsy at the RBWH from 2000-2015 were reviewed and those with biopsy confirmed AIN were selected. Cause of AIN, patient co-morbidities and renal indices were recorded when available and compared.
Results: 915 patients who underwent renal biopsy from 2000-2015 were reviewed and 40 patients were identified with biopsy confirmed AIN. The rate of AIN increased significantly over the study period (4 patients in 2000-03 vs. 19 patients in 2012-15; p=0.002). There was a marked increase in the number of women with AIN in the last four years of the study (2 patients in 2000-2003 vs. 13 patients in 2012-2015). Immune mediated causes of AIN (e.g. tubulo-interstitial nephritis and uveitis, sarcoidosis, Sjogren’s Syndrome) were more common in women (5 females vs. 2 males) and only occurred in women aged less than 55 years.
Conclusions: We demonstrate a significant increase in the number of patients with biopsy confirmed AIN and provide evidence of an increase in rates of younger women with immune mediated AIN. Although preliminary, these results support the trend identified by the AIHW and suggest that younger women may have a heightened risk of immune mediated AIN.