In large saucepan, bring rhubarb, ketchup, water, onion, garlic, brown sugar, mustard, vinegar, Worcestershire sauce, salt and hot pepper sauce to boil. Reduce heat and simmer, stirring often, until rhubarb is tender, about 20 minutes.
Transfer to blender or food processor; purée until smooth. Let cool. (Make-ahead: Refrigerate in airtight containers for up to 1 week or freeze for up to 1 month.) Makes 2 ½ cups.