Every sentence below is grammatical, and the paragraph is still exhausting to read — because each one dumps its new material at the front and its familiar material at the back. Re-phrase them one at a time. A sentence should open on what the reader already has and end on what is new, so the chain closes and the grammatical subjects stop wandering.
0 What the previous paragraph handed you
… and the effect showed up in one clinic after another. That pattern is the thing this paragraph now has to explain.
Old first, new last. English readers read the front of a sentence as its topic and the end as its emphasis. Break that pattern and every sentence becomes a small act of reorientation.