VIDEO: Risk factors for IgA nephropathy still unclear

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We don't know what causes a patient to develop IgA nephropathy and others not. We know that some forms of IgA nephropathy are familial, suggesting a genetic predisposition that is inherited. We also know that some populations have a higher prevalence of IgA nephropathy than others, such as countries from far East Asia, like China and Japan, which report a much higher prevalence of IgA nephropathy than the rest of the world. And in Africa and among people from African ancestry, IgA nephropathy is nearly absent. We also see IgA nephropathy as being associated with other autoimmune disorders, but we have not pinpointed the exact marker that predicts the risk of developing IgA nephropathy in a given individual.

Once diagnosed, the biggest risk factor for disease progression and major complication is the diagnosis of IgA nephropathy itself. This may sound nonsensical, but a diagnosis of IgA nephropathy alone is a tremendous risk for end-stage kidney disease, as recent epidemiological studies have taught us. Once diagnosed with IgA nephropathy, the factors strongly associated with the risk of a more rapid progression include the level of kidney function decline at the time of diagnosis, and the degree of tissue scarring on the biopsy, which together with the level of kidney function is likely a marker of delayed diagnosis, but can also represent a more aggressive form of IgA nephropathy.

Third, the degree of proteinuria, even levels that we historically considered mild, less than 0.5 gram per gram are associated with a 20% risk of kidney failure within 10 years. Again, this is worse than some cancer diagnosis. And fourth, blood pressure is not a variable that we consider modifiable factor in slowing progression of kidney disease and mitigating secondary cardiovascular complications. And fifth, most importantly, whether the patient receives adequate supportive care, including using maximally tolerated ACE inhibitor, or ARB, and SGL2 inhibitors and guideline-based lipid-lowering therapy all affect the long-term outcomes of patient with IgA nephropathy.