Drug-induced acute interstitial nephritis: A clinicopathological study and comparative trial of steroid regimens

Impact of Proton Pump Inhibitors on Kidney Function and Chronic Kidney Disease Progression: A Systematic Review

Proton pump inhibitors (PPIs) are widely prescribed medications for the management of various gastrointestinal disorders, primarily gastroesophageal reflux disease (GERD) and peptic ulcers. However, recent concerns have emerged regarding their potential adverse effects on kidney function and their role in the progression of chronic kidney disease (CKD). This systematic review aims to comprehensively analyze the existing literature to assess the impact of PPI use on kidney function and CKD progression. We took information from PubMed, PubMed Central (PMC), and Google Scholar articles from the last 10 years, from 2013 to 2023, and looked for links between PPI use and a number of kidney-related outcomes. These included acute kidney injury, a drop in the estimated glomerular filtration rate (eGFR), and new cases of CKD. The findings of this systematic review highlight the need for a thorough evaluation of the benefits and risks associated with PPI use, particularly in patients with pre-existing kidney conditions, in order to inform clinical decision-making and improve were taken out and looked at to see if there were any links between PPI use and different kidney-related events, such as acute kidney injury, a drop in the estimated eGFR, and the development of CKD. The review also explores potential mechanisms underlying PPI-induced nephrotoxicity. The findings of this systematic review highlight the need for a thorough evaluation of the benefits and risks associated with PPI use, particularly in patients with pre-existing kidney conditions, in order to inform clinical decision-making and improve patient care. Further research is warranted to better understand the complex interplay between PPIs, kidney function, and CKD progression.

Prognosis of severe drug-induced acute interstitial nephritis requiring renal replacement therapy

Objective

Drug-induced acute interstitial nephritis (DAIN) is often associated with improved outcomes, whereas some patients may still progress to chronic kidney disease (CKD). The aim of this study was to evaluate the prognosis of patients with severe DAIN requiring renal replacement therapy (RRT) at baseline, and to explore the risk factors of progression to CKD.

Methods

We performed a retrospective study of patients with severe DAIN confirmed by renal biopsies in our center over a 10 years period, all the patients received RRT at presentation. The clinical and pathological characteristics at baseline were recorded, and the outcomes (renal function recovered or progressed to CKD) during follow-ups were also evaluated. Univariate and multivariate logistic regression analysis were performed to identify the independent risk factors of progression to CKD.

Results

Seventy-two patients who met the inclusion criteria were enrolled, 13 patients (18.0%) progressed to CKD (GFR < 60 ml/min/1.73 m²) after at least 6 months of follow-up, the remaining 59 patients achieved a favorable renal function recovery. Compared with patients who achieved renal function recovery (recovery group), the patients progressed to CKD (progression group) were older and had longer interval from symptom onset to treatment with steroids. The peak serum cystatin C concentration was higher in progression group than recovery group. Higher score of interstitial fibrosis/tubular atrophy (IFTA) and more interstitial inflammatory cells infiltration were detected in renal tissue in progression group. According to multivariable analysis, higher peak cystatin C concentration (OR = 2.443, 95% CI 1.257, 4.746, p = 0.008), longer interval to treatment with corticosteroids (OR = 1.183, 95% CI 1.035, 1.352, p = 0.014) were independent risk factors of progression to CKD. The cutoff value of cystatin C concentration was 4.34 mg/L, at which the sensitivity and specificity were 76.9% and 89.3%, respectively; the cutoff value of interval to treatment with corticosteroids was 22.5 days, at which the sensitivity and specificity were 81.8% and 79.5%, respectively.

Conclusion

Renal function was reversible in majority of patients with severe DAIN requiring RRT when early identification and treatment. Higher peak cystatin C concentration and longer interval to treatment with corticosteroids associated with worse renal prognosis.

Clinical characteristics of childhood acute tubulointerstitial nephritis

BACKGROUND

Acute tubulointerstitial nephritis (ATIN) is a rare cause of acute kidney injury in children that can lead to chronic kidney disease. The aim of this study was to describe the presenting features, etiology, and clinical characteristics of childhood ATIN, and to evaluate treatment modalities and renal outcomes.

METHODS

The study included 38 patients who had been diagnosed with ATIN, were younger than 18 years old, and were admitted for at least 6 months of follow up.

RESULTS

The median age at diagnosis was 13.1 years (range 1.2-16.6 years). The female / male ratio was 1.37. The most common symptoms were abdominal pain (65.7%) and nausea / vomiting (55.2%). Twenty-three of the patients had a history of drug intake (60.5%), and the most active drugs in the etiology were non-steroidal anti-inflammatory drugs (56.5%). Eleven patients were given steroid therapy due to severe kidney involvement and rapid increases in serum creatinine values, and ten of those patients were drug-related ATIN cases. Other patients were given symptomatic treatment. Four patients needed several sessions of dialysis due to the severity of their acute renal failure. The follow-up creatinine and estimated glomerular filtration rate levels were not statistically different between the symptomatic and corticosteroid treated groups (P > 0.05).

CONCLUSIONS

Although our study was unable to show the beneficial effect of corticosteroid therapy on the extent of renal recovery, the use of steroids may be preferable in severe nephritis because of the rapid recovery of estimated glomerular filtration rate with corticosteroid therapy.

The safety of pulse corticosteroid therapy- Systematic review and meta-analysis

OBJECTIVE

To amass all available evidence from randomized controlled trials regarding the safety of pulse corticosteroids therapy, in order to establish its safety.

PATIENTS AND METHODS

All electronic databases from 1/1966 up to 02/2019 were reviewed to find all randomized controlled trials comparing pulse corticosteroids to oral corticosteroids or to placebo/no treatment. Two reviewers independently extracted and recorded data regarding type of corticosteroid treatment, dosages, length of treatment and follow-up. Risk ratios (RR) with 95% (CI) for differences between pulse corticosteroids and comparator were pooled using a fixed effect meta-analysis. The primary outcome was occurrence of severe adverse events (SAEs). Secondary outcomes included any adverse events (AEs), AEs requiring discontinuation, AEs per system involved and all-cause mortality.

RESULTS

A total of 64 trials were included: 18 trials which compared pulse corticosteroids to oral corticosteroids and 46 trials which compared pulse corticosteroids to placebo/no intervention. Pulse corticosteroids was not associated with increased risk for SAEs for both comparators: RR 0.77 (95% CI 0.52-1.14), and RR 0.99 (95% CI 0.93-1.06), respectively. Sensitivity analysis based on adequate allocation concealment and use of a valid AE grading did not alter the results. Subgroup analysis revealed no increased risk of specific SAEs or AEs with pulse corticosteroids compared to oral corticosteroids.

CONCLUSION

Pulse corticosteroids was not associated with an increase risk of SAEs and should be regarded as safe.

AIN’t got no easy answers: recent advances and ongoing controversies around acute interstitial nephritis

Acute interstitial nephritis (AIN) is a common cause of acute kidney injury that was first described in 1898. It is most commonly caused by drugs and infections, although other aetiologies are implicated. Here we review two papers published in this issue of Clinical Kidney Journal and provide an update on current advances and controversies relating to AIN. Nussbaum and Perazella describe the diagnostic tools (namely urinary and serum biomarkers) available for AIN and highlight that there is no single test that can accurately predict the diagnosis. As such, renal biopsy remains the gold standard. Wendt et al. present findings from a 20-year retrospective study of biopsy-proven AIN. They found that a high degree of inflammation was associated with a greater chance of renal recovery, in contrast to the presence of cortical scars, which were associated with a worse outcome. There was also a significant number who required renal replacement therapy. They advocate the use of a scoring system for AIN to help direct management. We also discuss new drugs associated with AIN (in particular new anticancer drugs) and unusual forms including granulomatous AIN. Finally, we discuss the opportunities for future research and how this may impact clinical practice.

Etiology and renal outcomes of acute tubulointerstitial nephritis: a single-center prospective cohort study in China

Background

The aim of this study was to explore the etiology, long-term renal outcomes and affecting factors of acute tubulointerstitial nephritis (ATIN).

Methods

Patients with biopsy-proven ATIN from 1 January 2005 to 31 December 2013 at Peking University First Hospital were enrolled in the study and received scheduled follow-up for at least 24 months. The causes of ATIN were defined at biopsy and reclassified during follow-up. Factors affecting renal recovery at 6 months post-biopsy and estimated glomerular filtration rate (eGFR) at 12 months post-biopsy and at the end of follow-up were analyzed.

Results

A total of 157 ATIN patients were enrolled, with an average follow-up of 48 months (range 24-108 months). A modified etiology spectrum was identified, with a decreased proportion of drug-induced ATIN (D-ATIN, 64% at biopsy to 50% after follow-up) and an increase in autoimmune-related ATIN (22-41%) with late-onset systemic manifestations in patients who had been classified as D-ATIN or ATIN of unknown cause. Recurrent kidney injury was observed in 51% of the patients with tubulointerstitial nephritis and uveitis syndrome (TINU), 53% of those with an autoimmune disease and 8% of those with D-ATIN, resulting in prolonged immunosuppressive treatment. By 12 months, decreased eGFR (<60 mL/min/1.73 m2) was observed in 47% of the patients with D-ATIN, 74% of those with TINU and 57% of those with other autoimmune diseases. In multivariable analysis, female sex, older age, presence of hypertension and recurrent kidney injury were independent risk factors for worse renal outcomes.

Conclusions

Our data demonstrate that autoimmune-related ATIN may present with systemic manifestations after kidney injury and is, therefore, commonly misdiagnosed. Repeated kidney injury is not uncommon in patients with ATIN. Scheduled follow-up is, therefore, critical for defining the exact etiology and proper management of ATIN.

Effect of steroids and relevant cytokine analysis in acute tubulointerstitial nephritis

Background

Acute tubulointerstitial nephritis (ATIN) is an important cause of acute kidney injury and often a potentially reversible disease. However, the role of steroids in ATIN remains controversial and the underlying mechanisms remain unresolved.

Methods

A total of 113 adult patients with biopsy-proven ATIN were recruited from three tertiary referral centers. Of 102 patients with idiopathic or drug-induced ATIN, outcomes such as renal recovery, end-stage renal disease, and all-cause mortality were compared between the steroid-treated and non-treated groups. Plasma and urine inflammatory cytokine levels at the time of biopsy were analyzed in patients (n = 33) using a bead-based multiplex assay and compared with those of healthy individuals (n = 40).

Results

Steroids were used in 92 (81.4%) of the total patients and in 82 (80.3%) patients with idiopathic or drug-induced ATIN. The rate of renal recovery and the risks of end-stage renal disease and mortality were not different between the steroid-treated and non-treated groups. Despite using a propensity score matching method (n = 20 in each group), none of the outcomes were different between the two groups. Several cytokines, such as monocyte chemotactic protein-1, interferon-α, and interleukin-6 and interleukin-8 levels, were markedly elevated in plasma and urine of patients compared with those in healthy individuals. However, cytokines related to Th2 response, such as IL-10, IL-33, were not different between the two groups.

Conclusions

Steroid use does not affect the overall outcome of ATIN. Based on the fact that targeting therapy should be investigated to improve outcomes, the present cytokine results will be helpful for developing a novel therapy for ATIN.

Electronic supplementary material

The online version of this article (10.1186/s12882-019-1277-2) contains supplementary material, which is available to authorized users.

The relationship between proton pump inhibitors and renal disease

Proton pump inhibitors (PPIs) bind to enzyme H⁺/K⁺-ATPase and inhibit its activity in the stomach, thus decreasing the secretion of gastric acid. PPIs may trigger acute interstitial nephritis, a potentially severe adverse event commonly associated with acute kidney injury. Studies have found that prolonged use of PPIs may increase the risk of chronic kidney disease (CKD). The increase in prescription and inadequate use of this class of medication calls for studies on the effects of prolonged PPI therapy on renal function. Therefore, this review aimed to analyze recent studies on the matter and discuss the possible consequences of the long-term use of PPIs on renal function.

Medication-Induced Interstitial Nephritis in the 21st Century

Interstitial nephritis is an immune mediated form of tubulointerstitial kidney injury that may occur secondary to drugs, autoimmune disease, infections, and hematologic disorders or as a reactive process. Drug-induced acute interstitial nephritis (DI-AIN) occurs in 0.5%-3% of all kidney biopsies and in 5%-27% of biopsies performed for acute kidney injury. Drugs are implicated in 70%-90% of biopsy-proved IN with a prevalence of 50% in less developed to 78% in more developed countries. DI-AIN typically is idiosyncratic because of a delayed hypersensitivity reaction, although some chemotherapeutic agents are permissive for immune upregulation and injure the kidney in a dose-related manner. Antibiotics are the most implicated class of medication in DI-AIN, followed by proton pump inhibitors, nonsteroidal anti-inflammatory agents, and 5-aminosalicylates. Diuretics, allopurinol, phenytoin and other anti-seizure medications, and H2 receptor antagonists are known offenders while chemotherapeutic agents are an under-recognized cause. The symptoms of DI-AIN are variable and often not specific; thus, kidney biopsy is required to make a firm diagnosis. The incidence of DI-AIN appears to be increasing, particularly in the elderly in whom kidney biopsy is underused, and identification of the offending agent may be complicated by polypharmacy. As rapid drug discontinuation may improve prognosis, the possibility of DI-AIN should always be considered in a patient with acute kidney injury.

Infection associated acute interstitial nephritis; a case report

Background

Acute interstitial nephritis (AIN) is a clinico-pathological syndrome associated with a variety of infections, drugs, and sometimes with unknown causes. It is a common cause of acute kidney injury (AKI) and subsequent renal impairment, which often times is under-diagnosed. Infection-associated AIN occurs as a consequence of many systemic bacterial, viral, and parasitic infec-tions; however, its incidence has decreased significantly after the advent of antimicrobials. Infection-associated AIN presents with both oliguric or non-oliguric renal insufficiency, without the classical clinical triad of AIN (fever, rash, and arthralgia). In this scenario the renal function is usually reversible after the infection is treated. In most cases, patients with acute renal failure present with extra-renal manifestations typically detected in underlying infections. Renal biopsy serves as the most definitive test for both the diagnosis and prognosis of AIN.

Case Presentation

In this paper, we will address one such case of biopsy-proven AIN. In this case, the patient presented with severe AKI induced by anaerobic streptococcus, leading to a periodontal abscess, which was successfully treated with corticosteroids and requiring renal replacement therapy (RRT).

Conclusions

AIN should be considered in the differential for unexplained AKI. Initial management should include conservative therapy by withdrawing any suspected causative agent. Renal biopsy is needed for confirmation in cases where kidney function fails to improve within 5–7 days on conservative therapy. Risk of immunosuppression is very important to consider when giving steroids in patients with infection induced AIN, and steroids may have to be delayed until the active infection is completely controlled.