Perioperative Opioid Use and Dosage Trajectories Vary Depending on Pain Outcome Classification and Bodily Pain in Patients who Catastrophize About Their Pain: A Secondary Analysis of a Randomized Trial in Knee Arthroplasty.

Opioid use and dosage following knee arthroplasty (KA) has not been reported for subgroups with persistent moderate pain versus rapidly improving mild pain, externally validated from prior work. We determined if opioid use and dosage varied for persons classified into these externally validated subgroups. A secondary purpose determined if bodily pain scores are associated with the outcome subgroup. This was a secondary analysis of a prospective no-effect randomized clinical trial conducted on 384 participants with pain catastrophizing and scheduled for KA. Data were collected preoperatively and at 2-, 6-, and 12-month following surgery. Two-piece latent class growth curve analyses applied previously validated pain outcomes to determine subgroup outcome trajectories for the proportion of opioid users and oral morphine equivalent (OME) dosages. Substantial trajectory separation was found for opioid use and OME. Specifically, the average OME dosage for the persistent moderate pain subgroup was more than double that for the other outcome subgroup. The average preoperative opioid daily OME dosage for 170 patients reporting opioid use was 24.94 (95% [confidence interval] CI = 20.52, 29.38). Bodily pain was consistently higher for the persistent moderate pain subgroup compared to the other subgroup. Outcome subgroups in patients with pain catastrophizing demonstrated substantial differences in opioid use and dosage and were predicted by high pain catastrophizing, more bodily pain, and changes in bodily pain over time. The persistent moderate pain subgroup is at greater risk of opioid use and greater opioid dosages and should be targeted for preoperative screening and interventions to reduce opioid use and potential opioid misuse. PERSPECTIVE: More frequent and higher opioid dosage following KA was found for the persistent moderate pain subgroup compared to the other subgroup. Patients with persistent pain had worse catastrophizing, contralateral and ipsilateral lower extremity pain, low back pain, and whole body pain compared to the rapidly improving mild pain subgroup.