Validation of a consensus-based minimal clinically important difference (MCID) threshold using an objective functional external anchor

Robert J. Gatchel, Tom G. Mayer, Yunhee Choi, Roger Chou

Research output: Contribution to journalArticlepeer-review

25 Scopus citations


Background context: The minimal clinically important difference (MCID) is defined as the smallest change in an outcome that a patient would perceive as meaningful. The Initiative on Methods, Measurement and Assessment in Clinical Trials (IMMPACT) group proposed defining the MCID as a 30% improvement in self-reported pain or function. However, this MCID threshold has not been validated against an objective physical measure. Purpose: To test the validity of the IMMPACT-based MCID threshold, using an objective physical measure as an external anchor. Study design/setting: Prospective study of chronic disabling occupational lumbar disorder (CDOLD) patients completing a functional restoration program. Patient sample: A consecutive cohort of 743 CDOLD patients. Outcome measures: Self-report measures of pain-related function were compared with an objective lifting measure, the progressive isoinertial lifting evaluation (PILE), obtained after treatment. Methods: The association between reporting 30% or greater improvement (the IMMPACT's MCID key criterion) and the PILE score after treatment was assessed. Results: A 30% or greater improvement on the self-report measures was significantly associated with improvement in physical function on the PILE task. Conclusions: Despite extensive use of the MCID to evaluate effects of treatment in spinal disorders, this is the first empirical documentation of the validity of the IMMPACT's 30% change criterion compared with an objective physical anchor.

Original languageEnglish (US)
Pages (from-to)889-893
Number of pages5
JournalSpine Journal
Issue number8
StatePublished - Aug 2013


  • Chronic disabling occupational lumbar spinal disorders
  • Functional restoration
  • Minimal clinically important difference (MCID)
  • PILE (progressive isoinertial lifting evaluation)

ASJC Scopus subject areas

  • Surgery
  • Orthopedics and Sports Medicine
  • Clinical Neurology


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