Big data is a major potential area of opportunity in health care.

And investors would do well to keep a close eye on it. Especially when companies start putting serious money behind decisions made based on predictive analytics.

Cigna (NYSE:CI), for example, recently signed a deal with AstraZeneca (NYSE:AZN) which could have big implications for both companies. Cigna will allow AstraZeneca's statin Crestor to be prescribed without prior authorization provided its computer model indicates that the patient is at a higher risk of atherosclerosis. This would help assure that members who need to go straight on Crestor -- instead of another statin -- are able to move to Crestor quickly. Typically, members have to go through traditional "step therapy" where they must try cheaper generics first.

Of course, IBM (NYSE:IBM) is a major player with Watson and its incredible potential to help identify appropriate treatment regimens with big data.

In the video below, from Market Checkup, the Motley Fool's health care-focused investing show, health care analysts Michael Douglass and David Williamson talk about big data and the exciting opportunities in this area.