Relationship Between Treatment Hours of Selected Disciplines And Change in Pain Impact During the Year Following Referral to an Interdisciplinary Pain Management Center: A Latent Class Analysis.

Introduction: Pain management clinics differ in treatments offered, and little evidence exists regarding which combinations of therapies result in best outcomes. This study analyzed clinical encounters and pain outcomes data for associations between treatment composition and outcomes. Methods: Retrospective observational study of 2,142 predominantly active-duty US service members referred to an interdisciplinary pain management center between 2014 and 2021. Latent class analysis was used to identify treatment groups with distinct outcome patterns during the year following initial assessment. The primary outcome measure was the National Institutes of Health Task Force on Research Standards for Chronic Low-Back Pain impact score. Results: Four distinct treatment groups were identified: 1 group engaged in conventional medical therapies alone ( n = 726, median 3.5 treatment hours), and 3 groups used a combination of conventional, psychological, rehabilitative, and complementary therapies, with different levels of treatment hours: low ( n = 814, median 15.7 h), medium ( n = 177, median 40.1 h), and high ( n = 425, median 72.5 h). All groups showed significant improvement in pain impact score from baseline up to 9 months but not at 12 months following initial assessment. At the 6-month time point, the group with high multimodal treatment hours had the most improvement in pain impact (-3.1 [95% CI -3.8, -2.4]) compared with the group using only conventional therapies (-1.0 points [95% CI -1.8, -0.1]) or with low multimodal treatment hours (-1.3 points [95% CI -1.9, -0.7]). There were no between-group differences at the 9- or 12-month time points. Conclusion: These results suggest that a combination of pain therapy approaches results in greater reduction in pain impact than the use of conventional medical treatment alone for up to 6 months after initiating therapy and that there may be a threshold of treatment hours that must be exceeded to achieve this benefit. Clinical trial registration: As this study is not a clinical trial, no registration was required.