proc sql;
create table Baseline_A_1 as
select
subject_id,
a1 as base_a1,
/* .. etc. .. , */
a10 as base_a10
from Scores
where visit=1;
/* pode ser feito dessa forma */
create table baseline_A_2 as
select *
from Scores(rename=(a1-a10=base_a1-base_a10) drop=b:)
where visit=1;
quit;