Yes, they do. It's 8.833% of the index. Health insurance makes up 13% of that part, or about 1% of the overall CPI. So even a large increase in health care contributes only a tiny amount to inflation.
They account for health insurance in a different way than you might think just looking at those 13% / 1% numbers might suggest. The short version is that if you pay $10000 in insurance premiums, but get $8000 of health care costs covered, they call that $2000 of insurance cost (since youd be paying the $8000 out of pocket otherwise). Of course, with the state of insurance in the US, its more complicated that that in reality.
I think the overall 8.8% figure is probably reasonably accurate for total health care costs, on average.
