Dr Laura Cuthbertson1, Dr REBECCA LING2, Dr CAMILLE KAY1, Dr GEOFFREY KIRKLAND1, Professor MATTHEW JOSE1,3, Dr RICHARD YU1
1Royal Hobart Hospital, Hobart, Australia , 2Launceston General Hospital , Launceston , Australia , 3University of Tasmania , Hobart, Australia
Background: Interstitial nephritis (IN) is characterized by inflammatory infiltrate in the kidney interstitium. Consensus guidelines for treatment are not yet established.
Aim: Evaluate the aetiology and treatment of kidney biopsy-proven IN across a 10-year period in Tasmania.
Methods: Patients in Tasmania from 2011 to 2021 with biopsy-proven IN and adequate digital medical records were included. Aetiology, kidney function and steroid use were recorded.
Results: Of 1650 biopsies performed, 47 (12 female) met our inclusion criteria. Mean age was 56-years (range 12 to 80 years) and mean eGFR at time of biopsy was 30ml/min/1.73m2 (range 12 to 96ml/min/1.73m2, 2 patients on haemodialysis). 36 (77%) were drug induced, 4 (8%) due to autoimmune/systemic disorders, 2 (4%) due to infection and in 5 (11%) the cause was not identified. Of drug induced IN, proton pump inhibitors (PPI) were the most common (35%). There were no cases of PPI induced IN in our dataset after 2019. NSAIDs were the second most common causative medication (4%), with 4 of 5 cases occurring in the second half of the study period. The first case of immune check-point inhibitor (ICI) IN was recorded in 2017, 2 subsequent cases in 2021. 19 (40%) patients were treated with varying doses and duration of steroids.
Conclusion: There is a wide range of aetiologies implicated in IN. Until 2019, PPIs accounted for 1/3 of drug induced IN, yet in our dataset there was no PPI induced IN after 2019, possibly reflecting increasing awareness and changes in PPI PBS prescribing. ICIs are an emerging cause of IN. There was great heterogenicity in the dosage and duration of steroids used in treatment of IN.
Biography:
Laura Cuthbertson is a first year Nephrology Advanced Trainee at Royal Hobart Hospital, Tasmania. She is an early career researcher and enjoys all topics kidney related. Outside of work, she enjoys running and listening to heavy metal music.