Differences in activity-related behaviour among patients with chronic low back pain.

The aim of the present study was to compare the subjectively reported and objectively assessed activity-related characteristics of patients with Chronic Low Back Pain (CLBP) who were classified according to their scores on the Patterns of Activity Measure-Pain (POAM-P) into avoiders, persisters, mixed performers (i.e. high scores on both avoidance and persistence behaviour) or functional performers (i.e. low scores on avoidance and persistence behaviour). Patients carried an electronic diary during 14 days to assess the self-reported activity and pain intensity levels in daily life. An accelerometer was used to objectively assess their activity level during the same time period. Results were available for 79 patients. Avoiders, persisters and mixed performers showed a higher level of self-reported disability than functional performers. Avoiders were characterized by a low level of self-reported habitual activities and persisters by long objectively measured daily uptime. The objectively assessed level of physical activity did not differ between the four groups. A further analysis tested the association between pain intensity levels and self-reported and objectively assessed daily life activity levels in avoiders and persisters. In persisters, a higher level of self-reported activities in daily life was related to increased pain. The objectively assessed activity level was not associated with pain intensity.