What it is very clearly saying is this: > The patient is a Black man, and the procedure may have special significance for Black patients [because they] suffer

What it is very clearly saying is this: > The patient is a Black man, and the procedure may have special significance for Black patients [because they] suffer high rates of end-stage kidney disease. I grant you that the grammar of the sentence does leave a smidgen of ambiguity. But I don't see any other plausible reading if you bring even a little bit of context to the interpretive exercise--which is just as much a part of reading as understanding the syntax. The author is justified in expecting that good faith readers will understand the final clause as explaining the clause that goes immediately before it. It's also a huge and unreasonable leap to go from "this sentence has a slight ambiguity" to "the sentence can be reasonably interpreted to mean that the procedure only works on black people." It can't.