• acute pain
• pain
• postoperative
• opioid-related disorders

We would like to thank Drs Luo, Wang and Nie for their letter entitled ‘Opioid consumption patterns after abdominal, joint, or spine surgery’.1 With respect to their question regarding the distribution of specific surgical procedures and opioid use trajectories we agree that there is some evidence of surgical-specific differences in the data in our study.2 For example, knee arthroplasty (including revisions) accounted for 74% and 75% of the high and persistent group membership among the orthopedic joint procedures, put only 55% of decreasing group membership. The difference in the persistent compared with the decreasing group among the joint procedures being different by 19% (95% CI 5 to 33, p=0.005). Although no other significant surgical-specific differences were found in our sample, we agree that larger, procedure-specific data is needed to identify the unique surgical procedural risk differences in opioid use patterns. Nevertheless, we believe an important contribution of our study was that similar patterns of opioid use were evident even in diverse surgical groups. In addition, the high use patterns were associated with longer opioid consumption postoperatively and with a greater risk of use of opioid beyond 6 months. We also agree with Drs Luo, Wang and Nie that factors such as central sensitization may play an important role in identifying patients at risk for increased opioid use postoperatively. In addition to central sensitization, opioid-induced hyperalgesia, opioid tolerance, widespread pain and psychological constructs such as anxiety and depression are likely important risk factors for increased opioid use postoperatively. We agree that our results should not construed to be definitive, but rather to serve as a catalyst for additional research into this area.