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IgA Nephropathy in Adults: A Review

Author/s: 
Sinead Stoneman, Jia Wei Teh, Michelle Marie O'Shaughnessy

Importance: IgA nephropathy (IgAN) is a chronic kidney disease involving deposition of IgA-containing immune complexes in the glomerulus, causing glomerular inflammation and scarring. It is the most common immune-mediated glomerular disease worldwide, and affects an estimated 198 887 to 208 184 persons in the US. Up to 50% of patients with IgAN develop kidney failure within 10 years of diagnosis.

Observations: IgAN typically presents with nephritic syndrome and usually occurs in younger adults, with a mean age at diagnosis of 34 to 45 years. Incidence is highest in East Asia. Approximately 60% of cases are detected incidentally with hematuria or proteinuria on urinalysis. Up to 30% of patients present with episodic visible hematuria, often concomitantly with an upper respiratory or gastrointestinal tract infection (synpharyngitic hematuria). Less common presentations include nephrotic syndrome (<5%) and rapidly progressive glomerulonephritis (<5%). When IgAN is suspected (due to hematuria, proteinuria, or reduced kidney function), initial workup should include quantification of proteinuria and assessment for other causes of nephritic syndrome (eg, lupus nephritis). Adults with suspected IgAN and proteinuria greater than or equal to 0.5 g per day should undergo kidney biopsy. The diagnosis of primary IgAN is based on presence of IgA-dominant immune deposits in the glomerular mesangium after excluding other causes of this histologic appearance, ie, IgA vasculitis, IgA-dominant infection-related glomerulonephritis, and secondary IgAN from diseases such as cirrhosis, inflammatory bowel disease, celiac disease, infection (eg, viral hepatitis), and autoimmune diseases (eg, axial spondyloarthritis). Based on the Kidney Disease: Improving Global Outcomes 2025 clinical practice guideline for the management of IgAN, treatment for patients with proteinuria greater than 0.5 g per day includes behavioral modifications (eg, dietary sodium <2 g/d, smoking cessation, weight control, exercise), antihypertensive medications for goal blood pressure less than 120/70 mm Hg, and therapies to reduce the formation of IgA-containing immune complexes (eg, targeted-release budesonide), decrease glomerular injury (eg, systemic glucocorticoids, iptacopan), and manage existing IgAN-induced nephron loss (eg, renin-angiotensin system inhibitor or dual endothelin angiotensin receptor antagonist [eg, sparsentan] alone or in combination with a sodium-glucose cotransporter 2 inhibitor).

Conclusions and relevance: IgAN is the leading cause of immune-mediated glomerular disease worldwide. Patients with suspected IgAN and proteinuria greater than or equal to 0.5 g per day should undergo kidney biopsy to confirm the diagnosis. Treatment of IgAN includes behavioral modifications, blood pressure management, and therapies to decrease formation of IgA-containing immune complexes (eg, targeted-release budesonide), reduce immune complex-mediated glomerular injury (eg, systemic glucocorticoids, iptacopan), and manage IgAN-induced nephron loss (eg, renin-angiotensin system inhibitor, dual endothelin angiotensin receptor antagonist, and sodium-glucose cotransporter 2 inhibitor).

Keywords 
Glomerulonephritis IGA Renal Insufficiency nephropathy glomerulus

Sodium-Glucose Cotransporter-2 Inhibitors and Major Adverse Cardiovascular Outcomes: A SMART-C Collaborative Meta-Analysis

Author/s: 
Siddharth M Patel, Yu Mi Kang, KyungAh Im, Brendon L Neuen, Stefan D Anker, Deepak L Bhatt, Javed Butler, David Z I Cherney

Background: Sodium-glucose cotransporter-2 inhibitors (SGLT2i) consistently improve heart failure and kidney-related outcomes; however, effects on major adverse cardiovascular events (MACE) across different patient populations are less clear.

Methods: This was a collaborative trial-level meta-analysis from the SGLT2i Meta-analysis Cardio-Renal Trialists Consortium, which includes all phase 3, placebo-controlled, outcomes trials of SGLT2i across 3 patient populations (patients with diabetes at high risk for atherosclerotic cardiovascular disease, heart failure [HF], or chronic kidney disease). The outcomes of interest were MACE (composite of cardiovascular death, myocardial infarction , or stroke), individual components of MACE (inclusive of fatal and nonfatal events), all-cause mortality, and death subtypes. Effect estimates for SGLT2i versus placebo were meta-analyzed across trials and examined across key subgroups (established atherosclerotic cardiovascular disease, previous myocardial infarction, diabetes, previous HF, albuminuria, chronic kidney disease stages, and risk groups).

Results: A total of 78 607 patients across 11 trials were included: 42 568 (54.2%), 20 725 (26.4%), and 15 314 (19.5%) were included from trials of patients with diabetes at high risk for atherosclerotic cardiovascular disease, HF, or chronic kidney disease, respectively. SGLT2i reduced the rate of MACE by 9% (hazard ration [HR], 0.91 [95% CI, 0.87-0.96], P<0.0001) with a consistent effect across all 3 patient populations (I2=0%) and across all key subgroups. This effect was primarily driven by a reduction in cardiovascular death (HR, 0.86 [95% CI, 0.81-0.92], P<0.0001), with no significant effect for myocardial infarction in the overall population (HR, 0.95 [95% CI, 0.87-1.04], P=0.29), and no effect on stroke (HR, 0.99 [95% CI, 0.91-1.07], P=0.77). The benefit for cardiovascular death was driven primarily by reductions in HF death and sudden cardiac death (HR, 0.68 [95% CI, 0.46-1.02] and HR, 0.86 [95% CI, 0.78-0.95], respectively) and was generally consistent across subgroups, with the possible exception of being more apparent in those with albuminuria (Pinteraction=0.02).

Conclusions: SGLT2i reduce the risk of MACE across a broad range of patients irrespective of atherosclerotic cardiovascular disease, diabetes, kidney function, or other major clinical characteristics at baseline. This effect is driven primarily by a reduction of cardiovascular death, particularly HF death and sudden cardiac death, without a significant effect on myocardial infarction in the overall population, and no effect on stroke. These data may help inform selection for SGLT2i therapies across the spectrum of cardiovascular-kidney-metabolic disease.

Keywords: diabetes mellitus; heart failure; meta-analysis; metabolic syndrome; renal insufficiency, chronic; sodium-glucose cotransporter-2 inhibitors.

Keywords 
heart failure metabolic syndrome Renal Insufficiency sodium-glucose cotransporter-2 inhibitors

Arteriovenous Access for Hemodialysis: A Review

Author/s: 
Charmaine E Lok, Thomas S Huber, Ani Orchanian-Cheff, Dheeraj K Rajan

Importance: Hemodialysis requires reliable vascular access to the patient’s blood circulation, such as an arteriovenous access in the form of an autogenous arteriovenous fistula or nonautogenous arteriovenous graft. This Review addresses key issues associated with the construction and maintenance of hemodialysis arteriovenous access.

Observations: All patients with kidney failure should have an individualized strategy (known as Patient Life-Plan, Access Needs, or PLAN) for kidney replacement therapy and dialysis access, including contingency plans for access failure. Patients should be referred for hemodialysis access when their estimated glomerular filtration rate progressively decreases to 15 to 20 mL/min, or when their peritoneal dialysis, kidney transplant, or current vascular access is failing. Patients with chronic kidney disease should limit or avoid vascular procedures that may complicate future arteriovenous access, such as antecubital venipuncture or peripheral insertion of central catheters. Autogenous arteriovenous fistulas require 3 to 6 months to mature, whereas standard arteriovenous grafts can be used 2 to 4 weeks after being established, and “early-cannulation” grafts can be used within 24 to 72 hours of creation. The prime pathologic lesion of flow-related complications of arteriovenous access is intimal hyperplasia within the arteriovenous access that can lead to stenosis, maturation failure (33%-62% at 6 months), or poor patency (60%-63% at 2 years) and suboptimal dialysis. Nonflow complications such as access-related hand ischemia (“steal syndrome”; 1%-8% of patients) and arteriovenous access infection require timely identification and treatment. An arteriovenous access at high risk of hemorrhaging is a surgical emergency.

Conclusions and Relevance: The selection, creation, and maintenance of arteriovenous access for hemodialysis vascular access is critical for patients with kidney failure. Generalist clinicians play an important role in protecting current and future arteriovenous access; identifying arteriovenous access complications such as infection, steal syndrome, and high-output cardiac failure; and making timely referrals to facilitate arteriovenous access creation and treatment of arteriovenous access complications.

Keywords 
Renal Replacement Nephrology Reproductive Health Arteriovenous Shunt Renal Insufficiency
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