title: Estimating the Risk of Chronic Pain: Development and Validation of a Prognostic Model (PICKUP) for Patients with Acute Low Back Pain.
abstract: Low back pain (LBP) is a major health problem. Globally it is responsible for the most years lived with disability. The most problematic type of LBP is chronic LBP (pain lasting longer than 3 mo); it has a poor prognosis and is costly, and interventions are only moderately effective. Targeting interventions according to risk profile is a promising approach to prevent the onset of chronic LBP. Developing accurate prognostic models is the first step. No validated prognostic models are available to accurately predict the onset of chronic LBP. The primary aim of this study was to develop and validate a prognostic model to estimate the risk of chronic LBP.
  
  
  
  We used the PROGRESS framework to specify a priori methods, which we published in a study protocol. Data from 2,758 patients with acute LBP attending primary care in Australia between 5 November 2003 and 15 July 2005 (development sample, n = 1,230) and between 10 November 2009 and 5 February 2013 (external validation sample, n = 1,528) were used to develop and externally validate the model. The primary outcome was chronic LBP (ongoing pain at 3 mo). In all, 30% of the development sample and 19% of the external validation sample developed chronic LBP. In the external validation sample, the primary model (PICKUP) discriminated between those who did and did not develop chronic LBP with acceptable performance (area under the receiver operating characteristic curve 0.66 [95% CI 0.63 to 0.69]). Although model calibration was also acceptable in the external validation sample (intercept = -0.55, slope = 0.89), some miscalibration was observed for high-risk groups. The decision curve analysis estimated that, if decisions to recommend further intervention were based on risk scores, screening could lead to a net reduction of 40 unnecessary interventions for every 100 patients presenting to primary care compared to a "treat all" approach. Limitations of the method include the model being restricted to using prognostic factors measured in existing studies and using stepwise methods to specify the model. Limitations of the model include modest discrimination performance. The model also requires recalibration for local settings.
  
  
  
  Based on its performance in these cohorts, this five-item prognostic model for patients with acute LBP may be a useful tool for estimating risk of chronic LBP. Further validation is required to determine whether screening with this model leads to a net reduction in unnecessary interventions provided to low-risk patients.
authors.affiliation: Prince of Wales Clinical School, University of New South Wales, Sydney, New South Wales, Australia.|Neuroscience Research Australia, Sydney, New South Wales, Australia.
authors.forename: Adrian C
authors.initials: AC
authors.lastname: Traeger
authors.affiliation: Institute of Public Health, University of Heidelberg, Heidelberg, Germany.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Henschke
authors.affiliation: Prince of Wales Clinical School, University of New South Wales, Sydney, New South Wales, Australia.|Neuroscience Research Australia, Sydney, New South Wales, Australia.
authors.forename: Markus
authors.initials: M
authors.lastname: Hübscher
authors.affiliation: Hunter Medical Research Institute and School of Medicine and Public Health, University of Newcastle, Callaghan, New South Wales, Australia.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Williams
authors.affiliation: The George Institute for Global Health, University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Kamper
authors.affiliation: The George Institute for Global Health, University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Christopher G
authors.initials: CG
authors.lastname: Maher
authors.affiliation: Neuroscience Research Australia, Sydney, New South Wales, Australia.|Sansom Institute for Health Research, University of South Australia, Adelaide, Australia.
authors.forename: G Lorimer
authors.initials: GL
authors.lastname: Moseley
authors.affiliation: Prince of Wales Clinical School, University of New South Wales, Sydney, New South Wales, Australia.|Neuroscience Research Australia, Sydney, New South Wales, Australia.
authors.forename: James H
authors.initials: JH
authors.lastname: McAuley
mesh_terms: D000328:Adult; D001315:Australia / Q000453:epidemiology; D059350:Chronic Pain / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology; D008297:Male; D008875:Middle Aged; D008962:Models, Theoretical; D011379:Prognosis; D011446:Prospective Studies; D012306:Risk