since 5 years ago what was the last id of the ward of patient 2498?
select transfers.wardid from transfers where transfers.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 2498 ) and transfers.wardid is not null and datetime(transfers.intime) >= datetime(current_time,'-5 year') order by transfers.intime desc limit 1