Nomogram to Predict Kidney Function Recovery After DI-AIN

Drug-induced acute interstitial nephritis (DI-AIN) is a common cause of acute kidney injury. The standard treatment is corticosteroid therapy (CS) and withdrawal of the problem-causing drug, but even with treatment, up to 50% of patients do not fully recover kidney function.

Fernando Caravaca-Fontán and other researchers conducted a retrospective, observational study to develop and validate a predictive nomogram to assess the probability of complete recovery (CR) of kidney function at 6 months after treatment for DI-AIN. Their findings were presented at the 61st European Renal Association Congress.

The dataset was divided randomly into a training group (n=64) and a validation group (n=64). The team used least absolute shrinkage and selection operator (LASSO) regression to screen the main predictors of CR (serum creatinine value <25% of the last value before DI-AIN) and to build the nomogram. They assessed the nomogram’s accuracy using discrimination and risk calibration in both sets.

The study included 224 patients with DI-AIN who were treated with CS between 1996 and 2023. Median age of participants was 70 years (interquartile range, 57-76 years); 115 patients (51%) were male. At 6 months after treatment with CS, 51 (31%) patients in the training group and 19 (32%) in the validation group achieved CR.

LASSO variables used to build the nomogram included age, gender, degree of interstitial fibrosis, and time to CS initiation. The area under the curve (AUC) of the nomogram was 0.809 (95% CI, 0.721-0.880), demonstrating good discrimination. The AUC after 1000 instances of bootstrap self-sampling for validation was 0.837 (95% CI, 0.705-0.931), indicating good predictive stability. Predicted outcomes aligned with observations, and decision curve and clinical impact curve analyses suggested clinical benefit.

Source: Caravaca-Fontán F, Praga M, Fernández-Juárez G. Development and validation of a nomogram for predicting complete kidney function recovery after drug-induced acute interstitial nephritis. Abstract #1347. Presented at the 61st European Renal Association Congress; May 23-26, 2024; Stockholm, Sweden.