Most patients with medication-related acute interstitial nephritis (AIN) will have significant impairment of kidney function after an episode of AIN.[1]Raghavan R, Eknoyan G. Acute interstitial nephritis - a reappraisal and update. Clin Nephrol. 2014 Sep;82(3):149-62.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4928030
http://www.ncbi.nlm.nih.gov/pubmed/25079860?tool=bestpractice.com
[11]Perazella MA, Markowitz GS. Drug-induced acute interstitial nephritis. Nat Rev Nephrol. 2010 Aug;6(8):461-70.
http://www.ncbi.nlm.nih.gov/pubmed/20517290?tool=bestpractice.com
About 40% to 60% of patients have chronic kidney disease (glomerular filtration rate <60 mL/minute) after AIN, some of whom will require chronic renal replacement therapy.[41]Caravaca-Fontán F, Shabaka A, Sánchez-Álamo B, et al. Recurrent acute interstitial nephritis: what lies beneath. Clin Kidney J. 2021 Jan;14(1):197-204.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7857806
http://www.ncbi.nlm.nih.gov/pubmed/33564419?tool=bestpractice.com
Tubulointerstitial fibrosis on biopsy remains a long-term consequence of AIN, and a higher degree of fibrosis is associated with a lower rate of kidney function recovery after AIN.[11]Perazella MA, Markowitz GS. Drug-induced acute interstitial nephritis. Nat Rev Nephrol. 2010 Aug;6(8):461-70.
http://www.ncbi.nlm.nih.gov/pubmed/20517290?tool=bestpractice.com
Delay in diagnosis, longer exposure to triggering drugs, and delay in initiation of corticosteroids are also associated with worse recovery of kidney function.[3]Muriithi AK, Leung N, Valeri AM, et al. Biopsy-proven acute interstitial nephritis, 1993-2011: a case series. Am J Kidney Dis. 2014 Oct;64(4):558-66.
http://www.ncbi.nlm.nih.gov/pubmed/24927897?tool=bestpractice.com
[42]Chen D, Luo C, Tang Z, et al. Delayed renal function recovery from drug-induced acute interstitial nephritis. Am J Med Sci. 2012 Jan;343(1):36-9.
http://www.ncbi.nlm.nih.gov/pubmed/22143122?tool=bestpractice.com
In patients prescribed immune checkpoint inhibitors, similar to other immune related adverse events, immune checkpoint inhibitor-related AIN is associated with lower mortality at 1 year than immune checkpoint inhibitor-unrelated acute kideney disease. AIN may be a marker of immune checkpoint inhibitor therapy efficacy in these patients.[43]Baker ML, Yamamoto Y, Perazella MA, et al. Mortality after acute kidney injury and acute interstitial nephritis in patients prescribed immune checkpoint inhibitor therapy. J Immunother Cancer. 2022 Mar;10(3):e004421.
https://www.doi.org/10.1136/jitc-2021-004421
http://www.ncbi.nlm.nih.gov/pubmed/35354588?tool=bestpractice.com