USUBJID: subject ID.
AVISIT: visit number.
ARMCD: treatment, TRT or PBO.
RACE: 3-category race.
SEX: sex.
FEV1_BL: FEV1 at baseline (%).
FEV1: FEV1 at study visits.
WEIGHT: weighting variable.
VISITN: integer order of the visit.
VISITN2: coordinates of the visit for distance calculation.