The prognosis of acute low back pain in primary care in the United States: a 2-year prospective cohort study.

STUDY DESIGN: Prospective cohort study.

OBJECTIVE: To assess the prognosis of patients presenting with acute low back pain (LBP) in a primary care setting in the United States.

SUMMARY OF BACKGROUND DATA: Practice guidelines for acute LBP based on return-to-work outcomes underestimate the development of chronic pain in the primary care setting. Because of differences in inclusion criteria, chronic pain definitions, and national health systems, prognostic cohort studies have reported a wide range of results limiting interpretation and generalization. Current data from carefully designed prognostic studies of acute LBP are lacking for the US primary care system.

METHODS: Members of a large health service organization were enrolled after seeking medical care for acute LBP, with or without sciatica, of up to 30 days duration, with no episode in the past 12 months and no history of spine surgery. We conducted phone interviews at baseline, 6 months, and 2 years. Based on receiver operating characteristic analyses, a combination of global perceived recovery with pain intensity was used as primary outcome for chronic pain. Recurrence and multiple secondary outcomes were assessed to allow for comparison with other studies.

RESULTS: Six hundred five patients had an average pain intensity of 5.6 (numeric rating scale = 0-10) and disability of 15.8 (Roland-Morris scale = 0-24). Eight percent had declared sick leave between pain onset and baseline interview. Thirteen percent of 521 patients (86% follow-up) experienced chronic pain at 6 months and 19% of 443 patients at 2 years. At 6 months, 54% had experienced at least 1 LBP recurrence, and 47% in the subsequent 18 months.

CONCLUSION: The prognosis of strictly defined acute LBP, with or without sciatica, is less favorable than commonly stated in practice guidelines based on failure to return to work. Broad initiatives to develop new means for the primary and secondary prevention of recurrent and chronic LBP are urgently needed.