what was the first value of rdw of patient 15905 since 110 months ago?
select labevents.valuenum from labevents where labevents.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 15905 ) and labevents.itemid in ( select d_labitems.itemid from d_labitems where d_labitems.label = 'rdw' ) and datetime(labevents.charttime) >= datetime(current_time,'-110 month') order by labevents.charttime asc limit 1