Mean Opioid Use Estimates May Mask Different Longitudinal Use Patterns in Orthopaedic Populations: Group-Based Trajectory Modeling is an Alternative.

Abstract

Using opioid use before and after knee arthroplasty as an illustrative example, we aimed to demonstrate the advantages of group-based trajectory modeling when investigating changes in opioid use over time. We used individual-level data on opioid use among patients aged ≥ 40 years undergoing knee arthroplasty retrieved from Danish national registries. We used milligram oral morphine equivalents per day as an outcome in group-based trajectory models to identify opioid use trajectories 4.5 years before and after knee arthroplasty. In total, 8,785 patients were included in the analyses. There were five distinct trajectories of opioid use identified through the group-based trajectory modeling: 'minimal' (32% of patients), 'minimal-to-low' (29%), 'low' (25%), 'low-to-high' (8%), and 'high' (6%). We identified five distinct opioid use trajectories among patients undergoing knee arthroplasty in Denmark using group-based trajectory modeling. The results highlight the importance of using alternative approaches when analyzing opioid use trajectories, as different use patterns can be overlooked when relying on group means.