A weird thought:

If you do this, it introduces an additional disincentive for wealthy people regarding public healthcare.

Not only would they have to carry the tax burden for the healthcare, they would also have to pay for the additional years of lifespan that result from improved health.

I'm not taking a stance either way, and in fact I have been impressed that some countries in Latin America have a functioning public health apparatus while far richer countries like the USA struggle to put such a thing in place. Just think it's an interesting multiplicative effect.