This Week in Nephrology — Sep 23, 2026

Welcome to This Week in Nephrology. This week we're covering 10 notable papers spanning kidney transplantation — from insurance-driven access barriers to intentional immune tolerance — glomerular disease diagnostics and immunosuppression, and a cluster of studies on chronic kidney disease risk, diet, drug safety and functional outcomes. Let's dive in.

We start with transplantation, where the most consequential paper this week isn't about a drug at all — it's about insurance. In JAMA, Shah and colleagues examined what happened after the 21st Century Cures Act opened Medicare Advantage enrolment to people with end-stage kidney disease [1]. Across more than six hundred thousand Medicare beneficiaries with kidney failure followed from 2021 through 2023, those enrolled in Medicare Advantage were transplanted at roughly 2.5 per thousand person-months compared with about 4.6 in traditional Medicare — after adjustment for demographics, dual eligibility, socioeconomic status, duration of kidney failure and referral region, that's close to a thirty percent lower transplant rate. New wait-listing was lower too, by about a quarter. And even among patients already on the wait list, Medicare Advantage enrolees were still transplanted less often, though the gap there was narrower. The absolute differences were widest in the youngest beneficiaries, those aged eighteen to forty-four — precisely the group with the most to gain from a transplant — and the pattern was stable across all three calendar years. This is observational, and unmeasured differences in who chooses Medicare Advantage could contribute, but the consistency and the magnitude are hard to dismiss. The practical implication is immediate: when you counsel a patient approaching kidney failure about plan enrolment, transplant access belongs in that conversation, and if your patient is in a Medicare Advantage plan, referral and wait-listing may need more active advocacy from you. Staying with transplantation but moving to the operating room and beyond, American Journal of Transplantation published two papers that sit at opposite ends of the ambition spectrum. The first is a randomized, double-blind, placebo-controlled trial of eculizumab to prevent delayed graft function in adult deceased donor kidney transplantation, reported by Marks and colleagues [2]. Just under three hundred patients received either complement blockade immediately before transplant and again eighteen to twenty-four hours afterwards, or placebo. The primary result was negative: eculizumab did not significantly reduce delayed graft function, with about thirty-six percent of the eculizumab group needing dialysis in the first week compared with about forty-two percent on placebo — a difference whose range of plausible values included no benefit at all. Safety was comparable between groups. The authors report a post hoc signal in recipients of expanded criteria donor kidneys managed with cold storage, where the absolute difference was close to eighteen percentage points, but that is hypothesis-generating only and should not change practice. For now, there remains no approved therapy that prevents delayed graft function.

The second transplant paper is a small but striking case series from Lum and colleagues, also in American Journal of Transplantation, describing intentional immune tolerance achieved years after transplantation rather than at the time of surgery [3]. Six healthy, stable recipients of HLA-matched sibling kidneys underwent nonmyeloablative conditioning followed by haematopoietic stem cell transplantation from their original donor. All six engrafted with durable mixed chimerism, all came off immunosuppression, and none developed graft-versus-host disease. Allograft function actually improved once immunosuppression was withdrawn. At publication five of the six remained immunosuppression-free, one of them for over three years; a single patient rejected fifteen months off therapy and required restarting maintenance immunosuppression. This is six patients with two-haplotype matched sibling donors, so its immediate applicability is narrow — but it establishes that the tolerance window is not limited to the peri-transplant period, which matters for the large population of stable recipients carrying the cumulative burden of lifelong immunosuppression. Turning to glomerular disease, Kidney International reports a step toward making anti-nephrin antibody testing something you could actually order. Gu and colleagues developed an automated chemiluminescence immunoassay using recombinant human nephrin ectodomain on magnetic microparticles, and tested it in 121 children with biopsy-confirmed minimal change disease or primary focal segmental glomerulosclerosis alongside disease and healthy controls [4]. Agreement with the research-standard immunoprecipitation Western blot was substantial, with overall concordance approaching eighty-seven percent, and the automated assay picked up antibody more often — about forty-one percent of patients versus twenty-eight percent — largely by detecting low-level positives. Clinically, antibody-positive patients with nephrotic-range proteinuria had more proteinuria, lower albumin, and steroid-sensitive disease, and higher antibody levels predicted shorter relapse-free survival. Most interesting for longitudinal care, among children in complete remission, anti-nephrin positivity was associated with relapse within three months, and the risk rose with antibody level. This is a paediatric cohort and needs external validation, but it points toward a serological monitoring tool for autoimmune podocytopathy analogous to what anti-PLA2R has become in membranous nephropathy.

On the treatment side, Kidney International Reports offers a sobering real-world look at avacopan. Juanet and colleagues conducted a retrospective comparative cohort study at Mayo Clinic of patients with ANCA-associated vasculitis and an estimated GFR below thirty at induction, comparing rituximab plus avacopan in thirty patients against rituximab alone in a hundred and twenty, with median GFRs around fifteen and roughly one in eight patients dialysis-dependent at baseline [5]. Avacopan delivered exactly what it was designed to deliver on steroids: cumulative prednisone exposure at twelve months fell from about 4.3 grams to 1.8 grams, and time to prednisone discontinuation shortened from over seven months to just over three. But renal remission rates did not differ significantly between groups, and longitudinal GFR trajectories were superimposable. One patient stopped avacopan for drug-induced liver injury, which resolved. So in severe renal vasculitis, treat avacopan as a glucocorticoid-sparing agent — a real and worthwhile benefit — rather than as something that rescues kidney function, and keep watching transaminases.

Rounding out this theme, American Journal of Kidney Diseases published a Core Curriculum review on the approach to haematuria [6], which is a useful refresher on confirming a positive dipstick with microscopy, the three red cells per high-power field threshold, and the newer American Urological Association emphasis on risk-stratified workup — tailoring imaging and cystoscopy to malignancy risk rather than subjecting every patient to the full evaluation. Our last theme is chronic kidney disease risk, diet, drug safety and function. American Journal of Kidney Diseases reports a large pharmacovigilance study by Ortega-Montiel and colleagues applying a tree-based scan statistic — essentially an automated hunt across the whole diagnostic code tree — to SGLT2 inhibitor safety in people with type 2 diabetes and stage three to four chronic kidney disease [7]. Using Medicare fee-for-service and commercial claims, they propensity-matched over twenty-two thousand pairs in the older cohort and nearly nine thousand in the commercial cohort, comparing new SGLT2 inhibitor users against new GLP-1 receptor agonist users. The method rediscovered the known signal — genital infections in both sexes, from outpatient codes — and found nothing new. Notably, no signals emerged from inpatient or emergency department codes. That's reassuring for a population routinely excluded from trials, though the authors acknowledge residual confounding and limited power.

Also in American Journal of Kidney Diseases, Uwatoko and colleagues randomized 36 Japanese patients with an estimated GFR under twenty, all on renin-angiotensin blockade, to four weeks of pre-prepared normoproteic diets at 0.8 grams per kilogram per day, with either seventy percent or fifty percent of protein from plant sources [8]. Of the three co-primary uraemic toxins, only trimethylamine N-oxide fell significantly with the plant-dominant diet; indoxyl sulfate and p-cresyl sulfate did not differ. The plant-dominant arm also raised venous bicarbonate and serum acetate, lowered parathyroid hormone, shifted the faecal microbiota away from pro-inflammatory genera toward short-chain fatty acid producers — and critically, serum potassium did not rise. That last point is the one to carry into clinic: the reflexive fear of hyperkalaemia with plant-based eating in advanced chronic kidney disease was not borne out here, albeit in a small, short, highly controlled feeding trial in patients selected for baseline potassium under 5.5.

Two more papers address who is at risk and how we measure them. In Hypertension, Ezzat and colleagues linked a history of hypertensive disorders of pregnancy to cardiovascular-kidney-metabolic syndrome staging in over two hundred thousand parous UK Biobank participants, with replication in the Women's Health Initiative [9]. Prior hypertensive disorders of pregnancy were associated with more than triple the odds of being at a higher cardiovascular-kidney-metabolic stage, and over a median follow-up approaching fourteen years, roughly a twenty-four percent higher rate of progression to established cardiovascular disease. Obstetric history is cheap, underused prognostic information — ask for it. And finally, from the CONVINCE trial cohort, also in American Journal of Kidney Diseases, Brinker and colleagues compared self-reported and performance-based physical function as predictors of death in 1,360 dialysis patients, about one in five of whom died over a median thirty months [10]. The four-item PROMIS patient-reported measure, the performance-based Physical Performance Test, and a composite of the two all predicted mortality comparably, with modest and essentially identical discrimination. Severe impairment flagged substantially higher mortality risk regardless of which instrument was used. In other words, a brief questionnaire performs about as well as a supervised physical test — which removes the main practical barrier to measuring function routinely in the dialysis unit. If you only have time for one paper this week, make it the JAMA analysis of Medicare Advantage and transplant access [1]. It documents a systematic, sizeable and persistent disadvantage in access to the single highest-value therapy in our field, tied to a coverage choice patients make with almost no awareness of its consequences — and you are the person positioned to inform that choice.

Here are the key takeaways from this week in Nephrology. Medicare Advantage enrolment is associated with roughly thirty percent lower kidney transplant rates and lower wait-listing than traditional Medicare, so raise transplant access during plan counselling and advocate actively for listed patients. Eculizumab did not significantly reduce delayed graft function in a randomized trial, so there is still no proven pharmacologic prevention. In severe renal ANCA-associated vasculitis, avacopan halved cumulative steroid exposure but did not improve renal remission or GFR trajectory — use it for what it does. An automated anti-nephrin assay tracked disease activity and predicted relapse in paediatric podocytopathy, moving this marker closer to clinical use. And in advanced chronic kidney disease, a plant-dominant but protein-adequate diet lowered trimethylamine N-oxide, improved acidosis and parathyroid hormone, and did not raise potassium, while a brief patient-reported physical function questionnaire predicted mortality as well as formal performance testing.

That's your roundup for This Week in Nephrology. The full transcript and references are available on the episode page in your AudioScholar library. This is an AI-curated summary — for clinical decisions, always consult primary sources and current guidelines. See you next week.

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This is an automated summary generated by artificial intelligence, which can make mistakes. Always review the original source materials.