Early Steroid Use Supports Renal Recovery in Drug-Induced Acute Interstitial Nephritis

Ayesha Aziz, MD

Acute interstitial nephritis (AIN) is an underdiagnosed cause of acute kidney injury. The common condition can be reversed. However, with limited data regarding clinial characteristics, the impact of steroids on managing drug-induced AIN has been up for debate within the medical community.

According to reports from biopsy registries, the average incidence of AIN is 2.8%, ranging from 1%-10%. When isolating biospsies performed on patients with acute kidney injury, the prevalence of AIN is 13% and drugs are responsible for a majority (70-75%) of cases.

Some studies have shown that steroids improve outcomes and can help with rapid recovery. Although, in other studies, there were no reported benefits on the rate and improvement of kidney function.

Reviewing Renal Biopsies

Ayesha Aziz, MD, Section of Nephrology, Department of Medicine, Aga Khan University Hospital, and a team of investigators sought to determine the cause and clinical presentation of acute intersititial nephritis and how the initiation of steroids affects recovery.

The retrospective review of medical records at the Aga Khan University Hospital included native renal biopsies that ocurred between 2007-2018 to assess the records of adult patients with biopsy-proven AIN whether the offending drug was identified or not.

Among 978 renal biopsies, a total of 48 (4.9%) were cases of acute interstitial nephritis. Early (≤ 3 weeks) or late (> 3 weeks) renal function recovery was one of the main outcomes of the study, along with hemodialysis (HD) dependence at 12 weeks.

The Results

Early use of steroids (≤ 11 days) was significantly associated with earlier onset of recovery compared with those who began steroid use after 11 days. The mean dose of prednisone was 0.8 ± 0.2 mg/kg per day.

Investigators found that three quarters of patients presented with estimated glomerular filtration rate (eGFR) < 15 mL/min/1.73 m2 (n = 36), out of which 58.3% (n = 21) required HD. 39 (81.3%) patients ended up receiving steroids.

Among the patients, the mean age was 47.6 ± 12.1 years and 56.3% were males. In half of patients with AIN, the offending agent could be identified with the most common being non-steroidal anti-inflammatory drugs (NSAIDs). The others identified were antibiotics, diuretics and proton pump inhibitor (PPI).

"Our data showed the benefit of earlier use of steroids in achieving rapid and complete renal recovery in drug-induced AIN in a low-middle-income country with frequent use of over-the-counter drugs," investigators wrote. "Late steroid use (≥ 3 weeks) was not associated with any further recovery at an additional risk of exposing patients to undue adverse effects."