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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

Dialysis for Chronic Kidney Failure: A Review

Author/s: 
Jennifer E Flythe, Suzanne Watnick

Importance: More than 3.5 million people worldwide and 540 000 individuals in the US receive maintenance hemodialysis or peritoneal dialysis for the treatment of chronic kidney failure. The 5-year survival rate is approximately 40% after initiation of maintenance dialysis.

Observations: Hemodialysis and peritoneal dialysis remove metabolic waste and excess body water and rebalance electrolytes to sustain life. There is no recommended estimated glomerular filtration rate (eGFR) threshold for initiating dialysis, and patient-clinician shared decision-making should help determine when to initiate dialysis. Persistent signs and symptoms of uremia (eg, nausea, fatigue) and volume overload (eg, dyspnea, peripheral edema), worsening eGFR, metabolic acidosis, and hyperkalemia inform the timing of therapy initiation. A randomized clinical trial reported no mortality benefit to starting dialysis at higher eGFR (10-14 mL/min/1.73 m2) vs lower eGFR (5-7 mL/min/1.73 m2) levels. Observational data suggested no differences in 5-year mortality with use of hemodialysis vs peritoneal dialysis. Cardiovascular (eg, arrhythmias, cardiac arrest) and infection-related complications of maintenance dialysis are common. In the US, hemodialysis catheter-related bloodstream infections occur at a rate of 1.1 to 5.5 episodes per 1000 catheter-days and affect approximately 50% of patients within 6 months of catheter placement. Peritonitis occurs at a rate of 0.26 episodes per patient-year and affects about 30% of individuals in the first year of peritoneal dialysis therapy. Chronic kidney failure-related systemic complications, such as anemia, hyperphosphatemia, hypocalcemia, and hypertension, often require pharmacologic treatment. Hypotension during dialysis, refractory symptoms (eg, muscle cramps, itching), and malfunction of dialysis access can interfere with delivery of dialysis.

Conclusions and relevance: In 2021, more than 540 000 patients in the US received maintenance hemodialysis or peritoneal dialysis for treatment of chronic kidney failure. Five-year survival rate after initiation of maintenance dialysis is approximately 40%, and the mortality rate is similar with hemodialysis and peritoneal dialysis. Decisions about dialysis initiation timing and modality are influenced by patient symptoms, laboratory trajectories, patient preferences, and therapy cost and availability and should include shared decision-making.

Keywords 
Acidosis chronic kidney failure Peritoneal Dialysis Renal Dialysis Uremia

Management of Hepatitis C in 2019.

Author/s: 
Kristen, Naggie, Susanna

In the United States, hepatitis C virus (HCV) infection affects more than 2 million adults and is the leading cause of liver-related mortality. Therapies that eradicate HCV may prevent progression to cirrhosis, liver decompensation, hepatocellular carcinoma, need for liver transplant, and death. HCV eradication also appears to reduce the risk of extrahepatic diseases, including cryoglobulinemic vasculitis and cardiovascularevents. Direct-acting antivirals (DAAs), oral drugs that target multiple mechanisms of the HCV lifecycle, have been usedincombination since 2013. Because of their efficacy and safety, the use of DAAshas substantiall yimproved HCV treatment and made HCV eradication possible for most patients, including patients with HIV infection, severe renal and hepatic impairment, and history of organ transplantation. Individuals living with HCV should be treated to reduce liver-related and all-cause morbidity and mortality and to prevent HCV transmission...

Keywords 
Pregnancy U.S. hepatitis vaccination RNA HIV Genotype liver

Proton Pump Inhibitor Use and Risk of Chronic Kidney Disease

Author/s: 
Lazarus, Benjamin, Chen, Yuan, Wilson, Francis P., Sang, Yingying, Chang, Alex R., Coresh, Josef, Grams, Morgan E.

Context

Proton pump inhibitors (PPIs) are among the most commonly used drugs worldwide, and have been linked to acute interstitial nephritis. Less is known about the relationship between PPI use and chronic kidney disease (CKD).

Objective

To quantify the association between PPI use and incident CKD in a population-based cohort.

Design, Setting and Participants

10,482 participants in the Atherosclerosis Risk in Communities (ARIC) study with an estimated glomerular filtration rate (eGFR) of ≥60mL/min/1.73m2 were followed from a baseline visit (1996–1999) to December 31, 2011. Findings were replicated in an administrative cohort of 248,751 patients with eGFR ≥60mL/min/1.73m2 from Geisinger Health System.

Exposure

Self-reported PPI use in ARIC, or an outpatient PPI prescription in the replication cohort. Histamine-2 receptor (H2) antagonist use was considered a negative control and active comparator.

Main Outcome Measure

Incident CKD, using diagnostic codes indicating CKD at hospital discharge or death. In the replication cohort, incident CKD was defined by outpatient eGFR <60 mL/min/1.73 m2.

Results

Compared to non-users, PPI-users were more often white, obese, and taking antihypertensive medication. In ARIC, PPI use was associated with incident CKD in unadjusted analysis (hazard ratio [HR], 1.45; 95% confidence interval [CI], 1.11–1.90), analysis adjusted for demographic, socioeconomic, and clinical parameters (HR, 1.50; 95% CI, 1.14–1.96), and in analysis with PPI ever-use modeled as a time-varying variable (adjusted HR, 1.35; 95% CI, 1.17–1.55). The association persisted when baseline PPI users were compared directly to H2-antagonist users (adjusted HR, 1.39; 95% CI, 1.01–1.91), and to propensity-score matched non-users (HR, 1.76; 95% CI, 1.13–2.74). In the replication cohort, PPI use was associated with CKD in all analyses, including a time-varying new user design (adjusted HR 1.24; 95% CI, 1.20–1.28). Twice-daily PPI dosing was associated with a higher risk (adjusted HR, 1.46; 95% CI, 1.28–1.67) than once-daily dosing (adjusted HR, 1.15; 95% CI, 1.09–1.21).

Conclusions

PPI use is associated with a 20%–50% higher risk of incident CKD. Future research should evaluate whether limiting PPI use reduces the incidence of CKD.

Keywords 
proton pump inhibitors chronic kidney disease interstitial nephritis
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