Focal segmental glomerulosclerosis (FSGS) is a histological pattern of glomerular injury, rather than a single disease, that is caused by diverse clinicopathological entities with different mechanisms of injury with the podocyte as the principal target of lesion, leading to the characteristic sclerotic lesions in parts (i.e., focal) of some (i.e., segmental) glomeruli. The lesion of FSGS has shown an increasing prevalence over the past few decades and is considered the most common glomerular cause leading to ESKD. Primary FSGS, which usually presents with nephrotic syndrome, is thought to be caused by circulating permeability factors that have a main role in podocyte foot process effacement. Secondary forms of FSGS include maladaptive FSGS secondary to glomerular hyperfiltration such as in obesity or in cases of loss in nephron mass, virus-associated FSGS, and drug-associated FSGS that can result in direct podocyte injury. Genetic FSGS is increasingly been recognized and a careful evaluation of patients with atypical primary or secondary FSGS should be performed to exclude genetic causes. Unlike primary FSGS, secondary and genetic forms of FSGS do not respond to immunosuppression and tend not to recur after kidney transplantation. Distinguishing primary FSGS from secondary and genetic causes has a prognostic significance and is crucial for an appropriate management. In this review, we examine the pathogenesis, clinical approach to distinguish between the different causes, and current recommendations in the management of FSGS.

Background and objectives: Drug-induced acute interstitial nephritis represents an emerging cause of acute kidney disease, especially among polymedicated elderly patients. Although corticosteroids are frequently used, controversy exists about the timing of initiation, efficacy, safety, and duration of treatment. Design, setting, participants, & measurements: We performed a retrospective study of 182 patients with biopsy-proven drug-induced acute interstitial nephritis from 13 Spanish centers. Exposure was defined as the length of corticosteroid treatment. The main outcome was the level of serum creatinine at month 6, with respect to baseline values. Results: The most common offending agents were nonsteroidal anti-inflammatory drugs (27%). In 30% of patients, the offending drug could not be identified. The median time to suspected drug withdrawal was 11 days (interquartile range, 5–22). All patients presented with acute kidney disease and were treated with corticosteroids. The mean initial dose of prednisone was 0.8±0.2 mg/kg per day. High-dose corticosteroid treatment was maintained for 2 weeks (interquartile range, 1–4). After 6 months, the mean recovered GFR was 34±26 ml/min per 1.73 m² and ten patients required maintenance dialysis. Use of high-dose corticosteroids for 3 weeks or treatment duration >8 weeks were not associated with better recovery of kidney function. In the multivariable analysis, delayed onset of steroid treatment (odds ratio, 1.02; 95% confidence interval, 1.0 to 1.04) and the presence of interstitial fibrosis of >50% on the kidney biopsy specimen (odds ratio, 8.7; 95% confidence interval, 2.7 to 27.4) were both associated with serum creatinine level at month 6 of >75%, with respect to baseline values. Conclusions: High-dose corticosteroid treatment for 3 weeks or prolonged treatment for >8 weeks were not associated with greater kidney function recovery in drug-induced acute interstitial nephritis. A delay in the initiation of corticosteroids resulted in worse recovery of kidney function.

Background and objectives: C3 glomerulopathy is a complement-mediated disease arising from abnormalities in complement genes and/or antibodies against complement components. Previous studies showed that treatment with corticosteroids plus mycophenolate mofetil (MMF) was associated with improved outcomes, although the genetic profile of these patients was not systematically analyzed. This study aims to analyze the main determinants of disease progression and response to this therapeutic regimen. Design, setting, participants, & measurements: We conducted a retrospective, multicenter, observational cohort study in 35 nephrology departments belonging to the Spanish Group for the Study of Glomerular Diseases. Patients diagnosed with C3 glomerulopathy (n=81) or dense deposit disease (n=16) between January 1995 and March 2018 were enrolled. Multivariable and propensity score matching analyses were used to evaluate the association of clinical and genetic factors with response to treatment with corticosteroids and MMF as measured by proportion of patients with disease remission and kidney survival (status free of kidney failure). Results: The study group comprised 97 patients (84% C3 glomerulopathy, 16% dense deposit disease). Forty-two patients were treated with corticosteroids plus MMF, and this treatment was associated with a higher rate of remission and lower probability of kidney failure (79% and 14%, respectively) compared with patients treated with other immunosuppressives (24% and 59%, respectively), or ecluzimab (33% and 67%, respectively), or conservative management (18% and 65%, respectively). The therapeutic superiority of corticosteroids plus MMF was observed both in patients with complement abnormalities and with autoantibodies. However, patients with pathogenic variants in complement genes only achieved partial remission, whereas complete remissions were common among patients with autoantibody-mediated forms. The main determinant of no remission was baseline proteinuria. Relapses occurred after treatment discontinuation in 33% of the patients who had achieved remission with corticosteroids plus MMF, and a longer treatment length of MMF was associated with a lower risk of relapse. Conclusions: The beneficial response to corticosteroids plus MMF treatment in C3 glomerulopathy appears independent of the pathogenic drivers analyzed in this study.

Acute respiratory distress syndrome associated with coronavirus infection is related to a cytokine storm with large interleukin 6 (IL‐6) release. The IL‐6‐receptor blocker tocilizumab may control the aberrant host immune response in COVID‐19 patients. In this pandemic, kidney transplant (KT) recipients are a high‐risk population for severe infection and showed poor outcomes. We present a multicenter cohort study of 80 KT patients with severe COVID‐19 treated with tocilizumab during hospital admission. High mortality rate was identified (32.5%), related with older age (HR 3.12 for those older than 60 years, p=0.039). IL‐6 and other inflammatory markers, including LDH, ferritin, and D‐dimer increased early after tocilizumab administration and their values were higher in non‐survivors. Instead, C‐reactive protein (CRP) levels decreased after tocilizumab, and this decrease positively correlated with survival (mean 12.3 mg/L in survivors vs. 33 mg/L in non‐survivors). Each mg/L of CRP soon after tocilizumab increased the risk of death by 1% (HR 1.01 [CI 1.004‐1.024], p=0.003). Although patients who died presented with worse respiratory situation at admission, this was not significantly different at tocilizumab administration, and did not impact on outcome in the multivariate analysis. Tocilizumab may be effective in controlling cytokine storm in COVID‐19 but randomized trials are needed.

The role of sodium-glucose cotransporter 2 inhibitors (SGLT2i) in the management glomerular/systemic autoimmune diseases with proteinuria in real-world clinical settings is unclear. Retrospective, observational, international cohort study. Adult patients with biopsy-proven glomerular diseases were included. The main outcome was the percentage reduction in 24-hour proteinuria from SGLT2i initiation to 3,6,9,12 months. Secondary outcomes included percentage change in estimated glomerular filtration rate(eGFR), proteinuria reduction by type of disease, and reduction of proteinuria ≥ 30% from SGLT2i initiation. Four-hundred and ninety-three patients with a median age of 55 years and background therapy with renin-angiotensin system blockers were included. Proteinuria from baseline changed by –35%, –41%, –45% and –48% at 3, 6, 9 and 12 months after SGLT2i initiation, while eGFR changed by –6%, –3%, –8%, –10.5% at 3,6,9 and 12 months, respectively. Results were similar irrespective of the underlying disease. A correlation was found between body mass index (BMI) and percentage proteinuria reduction at last follow-up. By mixed-effects logistic regression model, serum albumin at SGLT2i initiation emerged as predictor of ≥ 30% proteinuria reduction (odds ratio for albumin < 3.5 g/dl: 0.53; 95%CI 0.30–0.91; p = 0.02). A slower eGFR decline was observed in patients achieving a ≥ 30% proteinuria reduction: –3.7 versus –5.3 ml/min/1.73m²/year (p = 0.001). The overall tolerance to SGLT2i was good. The use of SGLT2i was associated with a significant reduction of proteinuria. This percentage change is greater in patients with higher BMI. Higher serum albumin at SGLT2i onset is associated with higher probability of achieving a ≥ 30% proteinuria reduction.

Background and objectives: Some studies suggest that the incidence of IgA nephropathy is increasing in older adults, but there is a lack of information about the epidemiology and behavior of the disease in that age group. Design, setting, participants, & measurements: In this retrospective multicentric study, we analyzed the incidence, forms of presentation, clinical and histologic characteristics, treatments received, and outcomes in a cohort of 151 patients ≥65 years old with biopsy-proven IgA nephropathy diagnosed between 1990 and 2015. The main outcome was a composite end point of kidney replacement therapy or death before kidney replacement therapy. Results: We found a significant increase in the diagnosis of IgA nephropathy over time from six patients in 1990–1995 to 62 in 2011–2015 (P value for trend =0.03). After asymptomatic urinary abnormalities (84 patients; 55%), AKI was the most common form of presentation (61 patients; 40%). Within the latter, 53 (86%) patients presented with hematuria-related AKI (gross hematuria and tubular necrosis associated with erythrocyte casts as the most important lesions in kidney biopsy), and eight patients presented with crescentic IgA nephropathy. Six (4%) patients presented with nephrotic syndrome. Among hematuria-related AKI, 18 (34%) patients were receiving oral anticoagulants, and this proportion rose to 42% among the 34 patients older than 72 years old who presented with hematuria-related AKI. For the whole cohort, survival rates without the composite end point were 74%, 48%, and 26% at 1, 2, and 5 years, respectively. Age, serum creatinine at presentation, and the degree of interstitial fibrosis in kidney biopsy were risk factors significantly associated with the outcome, whereas treatment with renin-angiotensin-aldosterone blockers was associated with a lower risk. Immunosuppressive treatments were not significantly associated with the outcome. Conclusions: The diagnosis of IgA nephropathy among older adults in Spain has progressively increased in recent years, and anticoagulant therapy may be partially responsible for this trend. Prognosis was poor. Podcast: This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2019_07_16_CJASNPodcast_19_08_.mp3