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

Abstract

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.

Keywords: Opioid; arthroplasty; knee; outcome; pain.

Figure 1.

Trajectories for rapidly improving mild pain subgroup (bottom trajectory) versus persistent moderate pain subgroup (top trajectory) opioid use proportion outcomes. The middle (darker gray) line represents the trajectory for the entire sample. Sample size was n = 321 for the rapidly improving mild pain subgroup, 63 for the persistent moderate pain subgroup and 384 for the entire sample. The data were collected prior to surgery and 2-months, 6- and 12-months following knee arthroplasty.

Figure 2.

Trajectories for rapidly improving mild pain subgroup (bottom trajectory) versus persistent moderate pain subgroup (top trajectory) oral morphine equivalents (OME) outcomes. The middle (darker gray) line represents the trajectory for the entire sample. Sample size was n = 321 for the rapidly improving mild pain subgroup, 63 for the persistent moderate pain subgroup and 384 for the entire sample. The data were collected prior to surgery and 2-months, 6- and 12-months following knee arthroplasty.

Figure 3.

The four panels indicate the scores for each of the four bodily pain measures, obtained at baseline and 12-months following knee arthroplasty. Scores are the marginal means derived from the within-person effects from the repeated measures MANOVA. Panel A illustrates trajectories for the persistent moderate pain versus rapidly improving mild pain subgroups for contralateral lower extremity pain scores. Panel B illustrates trajectories for the two outcome subgroups for ipsilateral lower extremity pain scores. Panel C illustrates trajectories for the two outcome subgroups for low back pain scores. Panel D illustrates trajectories for the two outcome subgroups for bodily pain scores.