Long-Term Outcomes in IgA Nephropathy
Clinical Journal of the American Society of Nephrology – 2023
IgA nephropathy is the most common primary glomerular disease.2 Defined by glomerular injury, patients experience proteinuria, hematuria, and progressive loss of estimated glomerular filtration rate (eGFR), ultimately leading to kidney failure (KF) due to IgA nephropathy.3,4
Advanced stages of chronic kidney disease (CKD) have been associated with cardiovascular disease (CVD) events and all-cause mortality.5 Proteinuria and lower eGFR have also been associated with a greater risk of CVD events.6 Changes in proteinuria have been associated with kidney failure.7,8 A registry-based study observed that almost all patients with IgA nephropathy progressed to kidney failure,9 indicating that patients are exposed to progressive CKD and thus likely an increased risk of CVD events.1
There is a need to assess the link between proteinuria reduction and slowing of eGFR decline with CVD events.1
The objective of this study was to assess the impact of proteinuria on CVD/all-cause mortality and KF/all-cause mortality outcomes.1
This observational, retrospective cohort study used Optum’s deidentified Market Clarity Data and proprietary Natural Language Processing (NLP) data.1
The study population included American adults with at least1:
Patients were divided into cohorts1:
Patients were excluded from the proteinuria-CVD/mortality cohort if there was1:
Patients were excluded from the proteinuria-KF/mortality cohort if there was1:
Patients were excluded from the KF-CKD/mortality cohort if there was1:
Elevated proteinuria was significantly associated with CVD and KF all-cause mortality (P<0.001)1
Proteinuria-CVD/mortality cohort
Patients with <1 g/d and patients with ≥1 g/d of proteinuria experienced CKD/all-cause mortality events over a median follow-up of 39.3 and 24.9 months, respectively.1 Proteinuria ≥1 g/day was significantly associated with CVD/all-cause mortality events (P<0.001).1
Proteinuria-KF/mortality cohort
Patients with <1 g/d and patients with ≥1 g/d of proteinuria experienced KF/all-cause mortality events over a median follow-up of 37.0 and 23.9 months, respectively.1 Proteinuria ≥1 g/day was significantly associated with KF/all-cause mortality events (P <0.001).1
Post-KF at baseline was significantly associated with CVD/all-cause mortality (P<0.001)1
Patients with a pre-KF status at baseline experienced CVD/all-cause mortality over a median follow-up of 44.4 months; patients with a post-KF status at baseline experienced CVD/all-cause mortality over a median follow-up of 33.5 months.1 A post-KF status at baseline was significantly associated with a greater risk of CVD/all-cause mortality (P<0.001).1
CKD stage progression and CVD events were linked with substantial incremental costs1
Exploratory analyses found that although highly variable, progressing CKD stages were associated with CVD events with substantial incremental costs.1
Elevated proteinuria and progression to KF due to IgA nephropathy were significantly associated with CVD/all-cause mortality.1 Additionally, pre-KF proteinuria was associated with KF/all-cause mortality.1
The authors hypothesize that reduction of proteinuria and slowing of progression to KF by novel IgA nephropathy therapies may reduce CVD risk and improve outcomes for patients.1
CKD, chronic kidney disease; CVD, cardiovascular disease; eGFR, estimated glomerular filtration rate; IgA, immunoglobulin A; KF, kidney failure; NLP, Natural Language Processing; SDS, signs, disease, and symptoms.
MA-DS-24-0028 | September 2024