I don't think this is possible. The only solution is to keep the same value in a variable.
EDIT: It's possible with scriping. For example, to get "Outline" effect parameter from an object by UID
var i = runtime.getInstanceByUid(localVars.objUID);
i.effects.forEach(function (e) {
if (e.name=="Outline") {
localVars.result = e.getParameter(localVars.parameterIndex);
}
});