IgA nephropathy (IgAN) is a chronic kidney disease where an antibody called immunoglobulin A (IgA) builds up in the kidney’s filters, known as glomeruli. This accumulation leads to inflammation and damage, impairing the kidneys’ ability to properly filter waste and fluids from the blood. Prognosis refers to the likely course or outcome of a disease, predicting how IgA nephropathy might progress for an individual.
Key Indicators of Prognosis
Several factors help predict the course of IgA nephropathy. One significant indicator is persistent proteinuria, which is the presence of excessive protein in the urine. Higher levels of protein in the urine, measured by tests like the albumin-to-creatinine ratio (uACR), suggest a less favorable outlook and a higher risk of faster progression to kidney failure. Regular monitoring of proteinuria is important for managing IgA nephropathy, helping adjust treatments and prevent further kidney damage.
High blood pressure (hypertension) is another factor influencing prognosis. Uncontrolled hypertension has been linked to disease progression, and its presence at diagnosis is often associated with a less favorable outcome. Reduced kidney function at the time of diagnosis, often assessed by the estimated glomerular filtration rate (eGFR), plays a role. A lower eGFR at diagnosis indicates significant kidney impairment, suggesting a less positive long-term outlook.
Age at diagnosis also affects the prognosis, with older age associated with a less favorable course. Men often experience a more aggressive form of the disease compared to women. Beyond these clinical markers, kidney biopsy findings provide insights into disease severity and progression. The Oxford classification system, also known as MEST-C, evaluates several features from a kidney biopsy: mesangial hypercellularity (M), endocapillary hypercellularity (E), segmental glomerulosclerosis (S), tubular atrophy/interstitial fibrosis (T), and crescents (C).
Each of these biopsy findings contributes to the prognostic assessment. For instance, tubular atrophy and interstitial fibrosis (T score) indicate chronic kidney damage and a worse prognosis. Segmental glomerulosclerosis (S score), which indicates scarring in parts of the glomeruli, points to a less favorable outcome. These pathological insights, combined with clinical indicators, help refine the prediction of disease trajectory.
Understanding Disease Progression
The progression of IgA nephropathy varies considerably among individuals, ranging from mild forms with stable kidney function to more aggressive courses. Some individuals may experience stable disease where kidney function remains preserved over many years, or even spontaneous remission, where the disease signs disappear. However, a significant proportion of people with IgA nephropathy will experience a gradual worsening of kidney function over time.
For some, the disease can progress slowly, and they may never reach kidney failure. For others, the progression can be more rapid, potentially leading to kidney failure within months or a few years. Studies indicate that about 25% to 30% of individuals with IgA nephropathy may develop end-stage kidney disease (ESKD) within 10 to 25 years of diagnosis. End-stage kidney disease signifies kidneys have lost most function and can no longer adequately filter waste.
When IgA nephropathy progresses to ESKD, individuals require treatments such as dialysis or a kidney transplant. Dialysis filters waste and excess fluid from the blood; a kidney transplant replaces the damaged kidney with a healthy one. The rate of decline in kidney function, measured by the estimated glomerular filtration rate (eGFR), is an important aspect of understanding progression. For instance, an annual eGFR decline of 3 ml/min per 1.73 m² is associated with a high risk of kidney failure within a person’s lifetime, particularly for those diagnosed at a younger age.
Managing IgA Nephropathy for Better Outcomes
Medical management and lifestyle adjustments play an important role in influencing the prognosis and improving long-term outcomes. A primary goal of treatment is to slow the rate of kidney damage and delay or prevent the onset of kidney failure. This often begins with supportive care measures focused on controlling blood pressure and reducing proteinuria.
Blood pressure control uses medications like renin-angiotensin system inhibitors (RASi), such as ACE inhibitors or ARBs, which also help reduce protein in the urine. Current guidelines suggest aiming for a systolic blood pressure less than 120 mm Hg in most patients. Reducing proteinuria to less than 1 gram per day is a significant treatment target, as lower levels are associated with improved kidney outcomes.
Lifestyle modifications also contribute to managing the disease. These include regular physical activity, maintaining a healthy body weight, and restricting dietary sodium intake. These changes can help manage blood pressure and overall kidney health. Regular monitoring of kidney function through blood and urine tests is part of the ongoing management plan, allowing providers to track the disease and adjust treatments.
Newer medications show promise in slowing disease progression. For example, sodium-glucose cotransporter-2 (SGLT2) inhibitors, originally used for diabetes, have demonstrated benefits in reducing proteinuria and kidney disease progression in individuals with chronic kidney disease, including those without diabetes. These interventions aim to preserve kidney function, impacting the long-term outlook for individuals with IgA nephropathy.