The relationship between regional pain with or without neuropathic symptoms and chronic widespread pain

This study was performed to test whether the risk of developing chronic widespread pain (CWP) in those with regional pain was augmented in those with symptoms of neuropathic pain (NP). Persons free of CWP completed the Douleur Neuropathique 4 (scores >= 3 indicating NP); demographics; Hospital Anxiety and Depression scale; Pittsburgh Sleep Quality Index; and pain medications. Participants were classified as having no pain, regional pain with no symptoms of NP ((NP) over bar), or regional pain with symptoms of NP ((NP) over bar). At the 12-month follow-up, participants with CWP were identified, Logistic regression estimated the odds ratio, with 95% confidence intervals, of CWP in the (NP) over bar and NP groups compared with no pain, and NP compared with NP. Partial population attributable risks estimated the proportion of CWP attributable to baseline (NP) over bar or NP exposure. One thousand one hundred sixty-two participants completed the baseline DN4 and provided pain data at follow-up: 523 (45.0%) had no baseline pain, 562 (48.4%) (NP) over bar, and 77 (6.6%) NP. One hundred fifty-three (13.2%) had CWP at 12 months: 19 (3.6%) no pain, 108 (19.2%) (NP) over bar, and 26 (33.8%) NP. (NP) over bar (2.9 [1.9-4.3]) and NP (2.1 [1.1-4.0]) predicted CWP after adjusting for demographics, Hospital Anxiety and Depression scale, Pittsburgh Sleep Quality Index, and medications. The partial population attributable risk was 41.3% (25.2-54.0) for (NP) over bar and 6.0% (0.1-11.6) for NP. The NP group were not more likely to develop CWP when compared directly with (NP) over bar (1.5 [0.8-2.8]). Neuropathic pain was relatively rare and predicted a small number of new-onset CWP cases. Using these estimates, treatments targeting NP would at best prevent 6% of CWP cases.