when did patient 86786 have the minimum value of creatinine last until 11/2105?
select labevents.charttime from labevents where labevents.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 86786 ) and labevents.itemid in ( select d_labitems.itemid from d_labitems where d_labitems.label = 'creatinine' ) and strftime('%y-%m',labevents.charttime) <= '2105-11' order by labevents.valuenum asc, labevents.charttime desc limit 1