P224
Outcomes of Patients With Acute Tubulointerstitial Nephritis at the Oxford Kidney
Unit
PK Judge1, T Dasgupta1, I Roberts1, CG Winearls1
1
Oxford Kidney Unit, Churchill Hospital, Oxford.
Introduction
Non-randomised studies suggest that withdrawal of causative agents, and early institution of
glucocorticoid therapy may be associated with better outcomes in acute tubulointersitial
nephritis (TIN). We quantified and assessed predictors of improvement in renal function
among those with biopsy proven acute TIN.
Methods
A retrospective review of all patients with biopsy-proven TIN presenting to the Oxford
Kidney Unit between 1999 and 2011 identified 134 patients. . Those with primary systemic
disease (n=14) were excluded. Estimated glomerular filtration rate was calculated using the
CKD-EPI formula. T tests were used to compare means. Multivariate regression was used to
model predictors for recovery of renal function.
Results
At presentation, the mean age was 61.5 years, and 43% were males. The median serum
creatinine at presentation was 339umol/L. Proton pump inhibitors were the attributed cause in
49 of 85 patients diagnosed to have drug-induced TIN.
103 patients were treated with glucocorticoids [median (IQR) dose: 40 (22.5) mg]. The mean
difference in baseline eGFR between groups receiving or avoiding steroids was not
statistically significant. The mean (SD) eGFR at final follow up was 57.7 (22.7)
ml/min/1.73m2, and was significantly better in those treated with steroids [mean difference
22.12 ml/min/1.73m2, 95%CI 30.62 to 13.61 ml/min/1.73m2 (p < 0.01)]. 57 (among 74
patients with known prior function) patients treated with steroids recovered to baseline
filtration function.
At final follow up, patients by CKD Stage were as follows: CKD Stage I or II: 19%, CKD
Stage III: 54.6%, CKD Stage IV: 15.5%, CKD Stage 5: 4.6%, CKD Stage Vd: 2.7%.
Stepwise selection procedures revealed a model containing steroid dose and baseline renal
function as the best predictors of improvement in filtration function, which was confirmed by
internal validation.
Conclusions
In our cohort, proton pump inhibitors were implicated in every second patient with druginduced TIN. Although non-randomised, our data suggest that steroid therapy is associated
with significantly better recovery of filtration function, such that at least every second patient
recovered prior filtration function.