Authors: Henrik Hein Lauridsen Claus Manniche Lars Korsholm Niels GrunnetNilsson Jan Hartvigsen
Publish Date: 2009/06/23
Volume: 18, Issue: 12, Pages: 1858-
Abstract
Understanding changes in patientreported outcomes is indispensable for interpretation of results from clinical studies As a consequence the term “minimal clinically important difference” MCID was coined in the late 1980s to ease classification of patients into improved not changed or deteriorated Several methodological categories have been developed determining the MCID however all are subject to weaknesses or biases reducing the validity of the reported MCID The objective of this study was to determine the reproducibility and validity of a novel method for estimating low back pain LBP patients’ view of an acceptable change MCIDpre before treatment begins Onehundred and fortyseven patients with chronic LBP were recruited from an outpatient hospital back pain unit and followed over an 8week period Original and modified versions of the Oswestry disability index ODI Bournemouth questionnaire BQ and numeric pain rating scale NRSpain were filled in at baseline The modified questionnaires determined what the patient considered an acceptable posttreatment outcome which allowed us to calculate the MCIDpre Concurrent comparisons between the MCIDpre instrument measurement error and a retrospective approach of establishing the minimal clinically important difference MCIDpost were made The results showed the prospective acceptable outcome method scores to have acceptable reproducibility outside measurement error MCIDpre was 45 larger for the ODI and 15 times larger for BQ and NRSpain compared to the MCIDpost Furthermore MCIDpre and patients posttreatment acceptable change was almost equal for the NRSpain but not for the ODI and BQ In conclusion chronic LBP patients have a reasonably realistic idea of an acceptable change in pain but probably an overly optimistic view of changes in functional and psychological/affective domains before treatment beginsWe thank Jytte Johannesen and Ida Bhanderi for administering the questionnaires Furthermore we would like to thank the management and staff at Backcenter Funen for their enthusiastic participation in the project A special thanks to the seven chiropractic clinics for their involvement in recruiting patients for the study The study was supported by the Foundation of Chiropractic Research and Postgraduate Education The Faculty of Health Science at the University of Southern Denmark and The European Chiropractic Union
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