Hospital systems spent more than $6.6 billion between April 2009 and April 2011 to build new facilities and update old ones, according to Illinois Hospital Association data. The spending spree underscores a race to gain and hold on to market share in one of the most competitive health care markets in the country. It also comes at a time of vast uncertainty in the industry, which faces drastic changes in the way care is delivered and paid for as part of the rollout of the national health care overhaul. The ramifications for patients, insurers and the hospitals themselves are myriad.