Predicting who develops chronic low back pain in primary care: a prospective study

Objectives To quantify the relative contribution of premorbid and episode specific factors in determining the long term persistence of disabling symptoms of low back pain. Design Prospective cohort study. Setting Two general practices in the south Manchester area. Participants 180 patients, who previously participated in a cross sectional population survey, who consulted because of low back pain during the study period. They were followed at 1 week and 3 and 12 months after consultation. Main outcome measure Persistent disabling low back pain in the 12 months after the consultation. Results Disabling low back pain persisted in one third of participants after consultation and was more common with increasing age, among those with a history of low back pain, and in women. Persistence of symptoms was associated with "premorbid" factors (high levels of psychological distress (odds ratio 3.3; 95% confidence interval 1.5 to 7.2), poor self rated health (3.6; 1.9 to 6.8), low levels of physical activity (2.8; 1.4 to 5.6), smoking(2.1; 1.0 to 4.3), dissatisfaction with employment (2.4; 1.3 to 4.5)) and factors related to thr episode of low back pain (duration of symptoms, pain radiating to the leg (2.6; 1.3 to 5.1), widespread pain (6.4; 2.7 to 15), and restriction in spinal mobility). A multivariate model based on six factors identified groups whose likelihood of persistent symptoms ranged from 6% to 70%. Conclusions The presence of persistent low back pain is determined not only by clinical factors associated with pain but also by the premorbid state.