As far as I know, if there are tracked changes in a document, Word will always open with those changed displayed, no matter what display state the document was in when it was last saved/closed.
If you just want to hide the changes temporarily you go into the Review ribbon and click Track Changes (in the Tracking group) to unhighlight it and then, in the same group, click the arrow next to All Markup and select either Simple Markup or No Markup.
As Bob says, if you want to get rid of it permanently, you have to either Accept All or Reject All. Those options are in the Changes group.