Steroid therapy in drug induced acute interstitial nephritis- Retrospective analysis of 83 cases

Drug-induced acute interstitial nephritis (DIAIN) is a common cause of acute deterioration of renal function. Early diagnosis and discontinuation of the offending drug usually lead to recovery of renal function. Steroid administration further hastens the recovery. However, the outcome of steroid-treated DIAIN is not well studied in the Indian scenario. We aimed to study the clinical profile and one-year renal outcome of DIAIN patients treated with steroids. We performed a retrospective study in biopsy-proven acute interstitial nephritis (AIN) and presumptive DIAIN patients who did not respond to discontinuation of the offending drug after five days of the diagnosis of AIN. Eighty-three DIAIN patients were included who were treated with 500 mg of methylprednisolone for three consecutive days followed by prednisolone of 0.5-1 mg/kg tapered over four to six weeks. We evaluated clinical profile, serum creatinine (SCr), and need of renal replacement therapy at the end of one year. We divided the patients into two groups: 1^st as complete responders group (CR) when SCr is <1.5 mg/dL at the end of one year and 2^nd as incomplete responders (IR) when it is ≥1.5 mg/dL and evaluated the outcome between two groups. In total, there were 39 (47%) CR and 44 (53%) were IR. Diabetes mellitus, present in a significant number of cases 27 (33%) was associated with poor response to steroids. Most common offending agents recognized were antibiotics (34%), nonsteroidal anti-inflammatory drugs (25%), herbal medications (13%), proton pump inhibitors (10%), and miscellaneous drugs (18%). There was no correlation between drug category and response to steroids. Interstitial fibrosis in renal biopsy was associated with poor response to steroids (4 cases in CR and 35 cases in IR, P ≤0.0001). Neutrophilic predominance in biopsy was associated with favorable response to steroids. Initial SCr and initial the requirement of dialysis support was not helpful in predicting the response to steroids and final recovery.