Evaluation of long-term outcomes with intrathecal opioid treatment: a comparison utilizing data derived from pain clinic populations in Australia and New Zealand.

Introduction: An obstacle to analysis of the long-term effectiveness of intrathecal (IT) opioids is absence of historical patient baseline data. The electronic Persistent Pain Outcomes Collaboration (ePPOC) is an initiative of the Faculty of Pain Medicine of the Australian and New Zealand College of Anaesthetists. Recently published ePPOC data has provided justifiable surrogate baseline data allowing opportunities for pain outcomes research into select patient treatment groups. Our aim was to compare long-term outcomes of IT opioid therapy with a surrogate baseline utilizing a large ePPOC data set for patients at the time of initial presentation to 36 pain clinics in Australia and New Zealand.

Methods: Study participants were 49 consenting patients receiving IT opioids as part of a long-term pain management regime for treating chronic non-cancer pain. Their data were compared with the large ePPOC data set (n = 13,343). The questionnaires comprised a demographic questionnaire, the Brief Pain Inventory, the Depression, Anxiety and Stress Scale, the Pain Catastrophizing Questionnaire, and the Pain Self-Efficacy Questionnaire.

Results: Compared with the ePOCC group, participants who received IT opioids long-term for the relief of chronic non-cancer pain reported significantly lower (p ≤ 0.001) pain severity (4.3 vs. 6.4), and pain interference scores (5.5 vs. 7), significantly lower depression (20.2 vs. 13.7), anxiety (9.6 vs. 14.1), stress (15.5 vs. 21), rumination (6.9 vs. 10), magnification (3.8 vs. 5.9), helplessness (9.7 vs. 14.1), general catastrophizing (20.4 vs. 29.8), and higher self-efficacy (29.5 vs. 20.7).

Discussion: The observed improvements in all measured pain variables have occurred in the context of comprehensive pain management, and therefore, may be attributable to pain reduction and not directly to IT opioid use or the device itself. Favourable pain management outcomes, in a select patient treatment group utilizing long-term IT opioid therapy, were demonstrated using the large-data ePPOC initiative, highlighting the research opportunities it provides.