The growth in numbers of accountable care organizations continued in 2014, although at a slower pace than in previous years. It may be too soon to know whether the slowdown is a blip or a sign of growth about to hit the wall.

Consultant Oliver Wyman studied Department of Health and Human Services data, and added its own research findings, to produce the report on 2014 ACO growth. What it found was that the numbers of Medicare patients covered by ACOs increased from 10 percent in 2013 to 11 percent in 2014. That represented a brake-slam compared to the uptick from 2012 to 2013 — 5 percent to 10 percent.

Meantime, non-Medicare patients covered by ACOs rose at about the same rate, with the 2014 numbers representing a drastic slowdown from 2012-2013 growth. Oliver Wyman said that the total number of ACOs stood at 585 at the end of 2014, a 12 percent increase over 2013. These numbers include 426 identified by HHS as Medicare approved ACOs and another 159 identified by Oliver Wyman's research.