Pattern of Cumulative Treatment Hours on Pain Impact and PROMIS Outcomes

Participation in interdisciplinary treatments is associated with improvement in pain intensity, physical function, and additional pain-related outcome domains. However, the effect of cumulative treatment hours on outcomes remains unknown among military patients. The present analysis examined the relationship between cumulative interdisciplinary treatment hours and pain management outcomes at a single interdisciplinary pain management center (IPMC).

This is a retrospective observational study of data previously collected as standard of care at the Madigan Army Medical Center, approved by the Institutional Review Board. We included patients who received treatment at the IPMC and completed at least two self-report assessment batteries: one at baseline and at least one between 90 and 180 days after baseline (n = 882). The primary outcome was pain impact. Secondary outcomes included fatigue, depression, anxiety, and sleep-related impairment.

Generalized additive models indicated that cumulative treatment hours were significantly associated with improvement in pain impact, fatigue, and depression. Patients who had higher baseline pain impact, who had mild or no depressive symptoms, and who were >40 years of age had greater improvements in pain impact following treatment, relative to those with lower pain impact, moderate-to-severe depressive symptoms, and were 40 years of age or younger, respectively. Additional research is needed to elucidate the effect of different therapies and additional patient factors in understanding the "therapeutic dose" of interdisciplinary pain management.

A higher number of cumulative treatment hours was associated with improvement of pain impact, fatigue, and depression among military personnel receiving interdisciplinary pain treatment. At least 30 hours of sustained interdisciplinary treatment appears to be the threshold for improvement in pain impact and related outcomes.