There are direct measures: someone needs a transplant or something of that nature, refusal is effectively shortening their life and some aggressive prosecutors might craft a case. There are less direct things, I expect a lot of them. say people dealing with long recoveries from things, there are good days and bad days and bouts of depression aren’t uncommon; could antidepressants prevent depression on related suicides? That’s an entire can of worms, people have fallen into depression because they’ve become addicted and can’t kick it, what if it was medical pain killers you’re addicted to? Then suppose some company spent half the funds on ED pills and breast augmentation and some more medically things were denied, you can spin that both ways as they might be doing what the bulk of their customers want. That one is interesting, you could break a bone and have surgical reconstruction and hopefully get a full recovery or maybe you just set it and naturally heal and maybe it’s not 100% fixed, only 85%, there is a substantial cost difference there…
For profit medicine and for profit health insurance is just riddled with moral hazard.