Recurrence of an Episode of Low Back Pain: An Inception Cohort Study in Emergency Departments

OBJECTIVES: To (1) determine the 1-year estimate of recurrence of low back pain (LBP) in a cohort of people presenting to emergency departments who have recently recovered from an episode of acute LBP in a middle-income country, (2) estimate a recurrence of LBP stratified by the STarT Back Screening Tool (SBST), and (3) determine prognostic factors for the recurrence of LBP. DESIGN: Prospective inception cohort study. METHODS: We included 238 patients who presented to emergency departments with recent-onset nonspecific LBP in Sao Paulo, Brazil. The outcome was the recurrence of an episode of LBP, assessed using 2 definitions: (1)12-month recall alone and (2) pain measurements at follow-up. Prognostic factors were determined by logistic regression. RESULTS: Within 1 year. the estimated recurrence of an episode of LBP ranged from 35% (79/225 events) (first definition) to 44% (100/226 events) (second definition). When patients were stratified by the SBST, the estimate of recurrence ranged from 29% to 37% (21.27/73 events) for low-risk patients, from 33% to 39% (24-28/72 events) for medium-risk patients, and from 43% to 56% (34.45/80 events) for high-risk patients. Age, perceived risk of persistent LBP, and disability were independent prognostic factors associated with LBP recurrence within 1 year. CONCLUSION: After recovering from a previous episode of acute LBP, 4 in every 10 patients experienced a recurrence within 1year. This estimate varied depending on the classification used in the SBST. Within 1 year, age, perceived risk of persistent LBP. and baseline disability were predictors of recurrence. (AU)