Among 77,703 statin initiators, prediction using baseline
variables only was poor (cross-validated C statistic ≤0.61). When
using 3 months of initial adherence to predict trajectory, prediction
was greatly improved among patients with an index supply
≤30 days (0.62 ≤C ≤0.91). With 4 months of initial adherence in the
model, prediction was strong for all patients (C ≥0.72), especially
for the best and worst trajectories (C = 0.90 and 0.94, respectively,
in patients with an index supply ≤30 days; and C = 0.83 and 0.90,
respectively, in patients with an index supply >30 days).