Background: Pain reported by a mannequin or predefined figure with body regions is important in evaluation of pain impact and development in general practice. Such reports are also of importance in classification of pain as being regional or widespread, as part of for example the 1990 ACR criteria for fibromyalgia. New proposed criteria for fibromyalgia have however omitted the evaluation of how painful regions are distributed and only focus on the number of regions.

Objectives: The aim was to study if the number of painful regions and their distribution (regional or widespread) independently predicted chronic widespread pain in a 12 year follow up of a cohort from the general population.

Methods: Within the Epipain-project a cohort of 2425 subjects from the general population in south Sweden answered a postal survey on pain and health. The questionnaire included a pain mannequin with 18 predefined regions. The number of regions was calculated and their distribution was analyzed with regard to ACR 1990 criteria for chronic widespread pain (CWP). Subjects were classified as having no chronic pain, chronic regional pain (CRP) or CWP. The survey was repeated after 3, 8 and 12 years. Odds ratios (Ors) for the independent variables pain distribution (NCP, CRP or CWP) and number of painful regions (0-18) with regard to report of CWP at follow up were analyzed with multiple logistic regression.

Results: Report of CWP vs. NCP at 3, 8 and 12 year follow was independently predicted by both pain distribution and the number of painful regions. ORs for subjects with CWP at baseline were 6.3 (95% CI 2.3-17.2), 5.0 (95% CI 1.9-13.3), and 4.0 (95% CI 1.6-9.7) at respectively follow up. Corresponding ORs for number of painful regions at baseline were 1.4 (1.3-1.6), 1.4 (1.2-1.5), and 1.3 (1.2-1.4).

Conclusions: Both the number of painful regions and their distribution (widespread or not) independently contributed to the prognosis for reporting chronic widespread pain in a 12 year follow up of pain development in the general population. This added prognostic value of pain distribution should be considered in evaluation of pain mannequins in general practice.