Burden of Immunoglobulin A Nephropathy (IgAN) and Risk Factors

Chee Kay Cheung, MBCHB, MRCP, PhD: IgA [immunoglobulin A] nephropathy is a serious autoimmune condition. It’s the most common primary glomerular disease worldwide. Interestingly, its prevalence increases as you go from the West to the East. It can affect people of any age but very commonly affects young adults and, therefore, the socioeconomic burden is very high. We estimate that about one-third of patients will develop kidney failure within about 20 years of diagnosis. Interestingly, there was a recent UK study of a renal registry that demonstrated higher rates of this. We studied about 2500 adults, and almost 80% of that cohort reached kidney failure within about 30 years of their diagnosis.

Common to other glomerular diseases, risk factors for disease progression include high blood pressure [and] reduced kidney function at diagnosis. And we know that levels of proteinuria are strongly correlated with risk of disease progression. Proteinuria is one of the strongest modifiable risk factors in IgA nephropathy. There are also some characteristics of IgA nephropathy, too, [that] are specific to the disease in determining prognosis in terms of kidney biopsy features. These have been now grouped into the Oxford classification of IgA nephropathy. Specific to these are degrees of mesangial hypercellularity, endocapillary hypercellularity, segmental sclerosis, and tubular interstitial fibrosis, and the presence of crescents. We can now, for an individual, use the IgA risk prediction tool to better determine an individual’s risk of a 50% decline in kidney function or in [reaching] kidney failure within around 7 years of their diagnosis. This can be done at the time of a kidney biopsy or 1 to 2 years following. That risk calculator uses certain variables, which include the factors that I described before. And you can put those into a website or an app through the QxMD website in order to calculate that. It’s important to note, however, that this risk prediction tool has not been validated for use in determining treatment decisions.

Transcript is AI-generated and edited for clarity and readability.