title: After an episode of acute low back pain, recurrence is unpredictable and not as common as previously thought.
abstract: METHODS
  Inception cohort study.
  
  
  OBJECTIVE
  To provide the first reliable estimate of the 1-year incidence of recurrence in subjects recently recovered from acute nonspecific low back pain (LBP) and to determine factors predictive of recurrence in 1 year.
  
  
  BACKGROUND
  Previous studies provide potentially flawed estimates of recurrence of LBP because they do not restrict the cohort to those who have recovered and are therefore eligible for a recurrence.
  
  
  METHODS
  We identified 1334 consecutive patients who presented to primary care with acute LBP; of these 353 subjects recovered before 6 weeks and entered the current study. The primary outcome measure was recurrence of LBP in the next year. Specifically, an episode of recurrence was defined in 2 ways: recall of recurrence at the 12-month follow-up and report of pain at the 3- or 12-month follow-up. Risk factors for recurrence were assessed at baseline. Pain intensity was assessed at 6 weeks, 3 months, and 12 months and recurrence at 12 months. Factors that could plausibly affect recurrence were chosen a priori and evaluated using a multivariable regression analysis.
  
  
  RESULTS
  Recurrence of LBP was found to be much less common than previous estimates suggest, ranging from 24% (95% CI = 20%-28%) using "12-month recall" definition of recurrence, to 33% (95% CI = 28%-38%) using "pain at follow-up" definition of recurrence. However, only 1 factor, previous episode(s) of LBP, was consistently predictive of recurrence within the next 12 months (odds ratio = 1.8-2.0, P = 0.00-0.05).
  
  
  CONCLUSIONS
  This study challenges the assumption that the majority of subjects will have a recurrence of LBP in a 1-year period. After the resolution of an episode of acute LBP, about 25% of subjects will have a recurrence in the next year. It is difficult to predict who will have a recurrence within the next year.
authors.affiliation: The George Institute For International Health, University of Sydney, Australia. tstanton@george.org.au
authors.forename: Tasha R
authors.initials: TR
authors.lastname: Stanton
authors.forename: Nicholas
authors.initials: N
authors.lastname: Henschke
authors.forename: Chris G
authors.initials: CG
authors.lastname: Maher
authors.forename: Kathryn M
authors.initials: KM
authors.lastname: Refshauge
authors.forename: Jane
authors.initials: J
authors.lastname: Latimer
authors.forename: James H
authors.initials: JH
authors.lastname: McAuley
mesh_terms: D000328:Adult; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D017116:Low Back Pain / Q000175:diagnosis / Q000453:epidemiology* / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement / Q000379:methods; D011237:Predictive Value of Tests; D012307:Risk Factors; D055502:Secondary Prevention