THU0694 The excess risk of disability in people with neuropathic pain when compared to those with nociceptive pain is explained by pain catastrophising and physical inactivity
Authors: J. Mcbeth, M. Mulvey, J. Anderson, A. Rashid, K. Druce
Journal: Annals of the Rheumatic Diseases (2018)

<h3>Background</h3> Neuropathic pain (NP) is associated with worse patient outcomes including poorer quality of life and increased disability and mortality when compared to persons with pain that is predominantly nociceptive (NCP). It is not known if the higher rate of co-morbid psychosocial factors (e.g. depression, fatigue) in persons with NP explains the increased risk of poor outcomes. <h3>Objectives</h3> To test the hypotheses that pain predominantly of NP origin would be associated with higher levels of disability when compared to NCP, and the excess risk would be independent of putative confounders. <h3>Methods</h3> 1587 participants in a population based prospective study completed a baseline and follow up questionnaire 12 months later. Participants were asked about the presence, location and duration of musculoskeletal pain and they completed the Douleur Neuropathique 4 (scores≥3 indicating NP). Participants were classified according to their pain reports as having no pain (NP), some pain with (SPn) and without (SP) NP, and chronic widespread pain American College of Rheumatology 1990 criteria) with (CWPn) and without (CWP) NP. The primary outcome was the Stanford Health Assessment Questionnaire (HAQ) from which the Standard Disability Index (HAQ-DI) was calculated. Participants also completed the Hospital Anxiety and Depression Scale (HADS), Chalder Fatigue scale (CF); the Pain Catastrophising Scale (PCS); Rapid Assessment of Physical Activity (RAPA); Social Support scale (SS); Joint Hypermobility scale (JH); Jenkins Sleep Scale (JSS). Ordered logistic regression tested the relationship between pain status at baseline and HAQ-DI at follow up with results expressed as odds ratios (OR) with 95% confidence intervals (CI). <h3>Results</h3> 1235 (77%) participants provided complete data and formed the cohort for this analysis. At 12 month follow up the mean (standard deviation) HAQ-DI score was 0.31 (0.62), with higher scores in women and older participants. After adjusting for age and sex, when compared to those with NP at baseline participants with SP were 3 times (OR=2.9, 95% CI (2.2, 3.9)) and those with SPn almost 9 times (8.7 (5.4, 14.0)) more likely to have higher HAQ-DI scores at follow up. Those with CWP were 8 (7.8 (5.7, 10.8)) and those with CWPn 38 (38.1 (23.3, 62.5)) times more likely to have higher HAQ-DI scores. When these associations were adjusted for putative confounders and baseline HAQ-DI scores having pain remained associated with increased HAQ-DI scores at follow up although the relationships were significantly attenuated, and the 95% CIs were similar across pain groups: SP 1.8 (1.3, 2.5); SPn 2.6 (1.4, 4.8); CWP 2.3 (1.6, 3.4); 3.3 (1.9, 6.0). The PCS helplessness scale (1.07 (1.01, 1.13)) and RAPA (0.93 (0.87, 0.99)) were significantly associated with 12 month HAQ-DI scores. <h3>Conclusions</h3> The increased risk of disability in persons with NP was not independent of common pain co-morbidities. Screening and targeting treatment for pain-related helplessness and physical inactivity has the potential to significantly improve disability outcomes for persons with NP. <h3>Disclosure of Interest</h3> None declared