Utility of accumulated opioid supply days and individual patient factors in predicting probability of transitioning to long-term opioid use: an observational study in the Veterans Health Administration - Hadlandsmyth, K; Mosher, H J; Vander Weg, M W; O'Shea, A M; McCoy, K D; Lund, B C (Pharmacol Res Perspect, 2020)