title: Prediction of sickness absence in patients with chronic low back pain: a systematic review.
abstract: OBJECTIVE
  To provide evidence of predictors for sickness absence in patients with non-specific chronic low back pain (CLBP), distinguishing predictors aimed at the decision to report sick (absence threshold) and decision to return to work (return to work threshold).
  
  
  METHODS
  Medical and psychological databases were searched, as well as citations from relevant reviews. In- and exclusion criteria were applied. Two reviewers assessed the methodological quality of the papers independently.
  
  
  RESULTS
  Many different predictors were studied, and few factors were studied more than once. Consistent evidence was found for own expectations of recovery only as predictor for the decision to return to work. Patients with higher expectations had less sickness absence at the moment of follow-up measurement. As expected, different predictors were found aiming at the absence threshold or the return to work threshold. Furthermore, predictors varied also with the measurement instruments used, timing of follow-up measurements, and definition of outcomes. Until now, too few studies are available to overcome several potential sources of heterogeneity.
  
  
  CONCLUSIONS
  No core set of predictors exists for sickness absence in general. The characteristics of the study including the decision to report sick or to return to work determined the influence of several predictors on sickness absence in patients with CLBP. Further research and use of a core set of measurements and uniform definitions are needed to predict sickness absence and return to work in patients with CLBP.
authors.affiliation: Center for Rehabilitation, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands. wietske.kuijer@han.nl
authors.forename: Wietske
authors.initials: W
authors.lastname: Kuijer
authors.forename: Johan W
authors.initials: JW
authors.lastname: Groothoff
authors.forename: Sandra
authors.initials: S
authors.lastname: Brouwer
authors.forename: Jan H B
authors.initials: JH
authors.lastname: Geertzen
authors.forename: Pieter U
authors.initials: PU
authors.lastname: Dijkstra
mesh_terms: D000041:Absenteeism; D016206:Databases, Bibliographic; D004651:Employment / Q000639:trends*; D006801:Humans; D017116:Low Back Pain / Q000453:epidemiology* / Q000534:rehabilitation; D009140:Musculoskeletal Diseases / Q000453:epidemiology* / Q000534:rehabilitation; D009784:Occupational Diseases / Q000453:epidemiology* / Q000534:rehabilitation; D011379:Prognosis; D018582:Sick Leave / Q000706:statistics & numerical data*