Actually, until Trump came into office, CBO's numbers was spot on. For example, they said that in 2016/2017, that health care spending would go up as ppl who had delayed taking care of issues came in to take care of them. 
And had it continued, per CBO, then by end of 2017, the health care spending would have plummeted, and we would have been back on a max 2-3% growth. That was the lowest that we have seen since the 80s.