[Chronic widespread pain and tender points in low back pain: a population-based study]

Abstract

Background: Clinical observation suggests a frequent coincidence of back pain (BP) and fibromyalgia (FMA). Based on data from a population survey on back pain we studied the hypothesis of FMA being a frequent underlying condition of BP. We additionally studied the association of the severity of back pain and both chronic widespread musculoskeletal pain and active tender points.

Probands and methods: Data from a regional two-stage survey on urban German residents (aged 25-74 years) of Luebeck/Northern Germany (N=3969) were reanalyzed. The survey combined a postal questionnaire screening with a subsequent medical-psychological examination. Only subjects with back pain on the day of filling in the questionnaire were invited (n = 875). The response and participation rates were 82% and 73%, respectively. The severity of back pain was graded according to Kohlmann and Raspe (1994; based on pain severity and disability). In assessing widespread pain and tender points and classifying FMA-cases, we followed the criteria of the American College of Rheumatology (Wolfe et al. 1990). Standardized psychometric scales were used to measure general health status, bodily complaints, depressiveness, and catastrophizing cognitions.

Results: In Luebeck, the overall point prevalence of back pain reached 39%. Among those invited and examined we found 27%, 25%, and 19% with back pain grade 1, 2 or 3, respectively. 29% reported no back pain on the day of examination. 12.6% of probands with actual back pain reported chronic widespread pain. The number of active tender points showed a significant and relevant association with back pain grade and was additionally correlated with all indicators of somatic and psychological distress.

Conclusion: Our data do not support the hypothesis of FMA as a frequent underlying condition of BP. We found, however, a close correlation between BP grade (and amount of distress) and tender points count. More severe forms of BP imply an increasing allodynia/hyperalgesia, itself being associated with a higher amount of somatic and psychological distress (Chronic severe) back pain seems to be more than simply pain in the back.