Journal article

Determination of the Oswestry Disability Index score equivalent to a "satisfactory symptom state" in patients undergoing surgery for degenerative disorders of the lumbar spine-a Spine Tango registry-based study.

  • van Hooff ML Department of Research, Sint Maartenskliniek, PO Box 9011, 6500 GM Nijmegen, The Netherlands. Electronic address: m.vanhooff@maartenskliniek.nl.
  • Mannion AF Department of Teaching, Research and Development, Spine Center Division, Schulthess Klinik, Lengghalde 2, 8008 Zurich, Switzerland.
  • Staub LP Institute for Evaluative Research in Medicine, University of Bern, Stauffacherstrasse 78, 3014 Bern, Switzerland.
  • Ostelo RW Department of Health Sciences & VU Medical Center, Department of Epidemiology and Biostatistics, EMGO Institute for Health and Care Research, VU University, PO Box 7057, 1007 MB Amsterdam, The Netherlands.
  • Fairbank JC Nuffield Department of Orthopaedics, Rheumatology, and Musculoskeletal Science NDORMS, Nuffield Orthopaedic Centre, University of Oxford, Windmill Rd, Oxford OX3 7HE, United Kingdom.
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  • 2016-06-26
Published in:
  • The spine journal : official journal of the North American Spine Society. - 2016
English BACKGROUND CONTEXT
The achievement of a given change score on a valid outcome instrument is commonly used to indicate whether a clinically relevant change has occurred after spine surgery. However, the achievement of such a change score can be dependent on baseline values and does not necessarily indicate whether the patient is satisfied with the current state. The achievement of an absolute score equivalent to a patient acceptable symptom state (PASS) may be a more stringent measure to indicate treatment success.


PURPOSE
This study aimed to estimate the score on the Oswestry Disability Index (ODI, version 2.1a; 0-100) corresponding to a PASS in patients who had undergone surgery for degenerative disorders of the lumbar spine.


STUDY DESIGN/SETTING
This is a cross-sectional study of diagnostic accuracy using follow-up data from an international spine surgery registry.


PATIENT SAMPLE
The sample includes 1,288 patients with degenerative lumbar spine disorders who had undergone elective spine surgery, registered in the EUROSPINE Spine Tango Spine Surgery Registry.


OUTCOME MEASURES
The main outcome measure was the ODI (version 2.1a).


METHODS
Surgical data and data from the ODI and Core Outcome Measures Index (COMI) were included to determine the ODI threshold equivalent to PASS at 1 year (±1.5 months; n=780) and 2 years (±2 months; n=508) postoperatively. The symptom-specific well-being item of the COMI was used as the external criterion in the receiver operating characteristic (ROC) analysis to determine the ODI threshold equivalent to PASS. Separate sensitivity analyses were performed based on the different definitions of an "acceptable state" and for subgroups of patients. JF is a copyright holder of the ODI.


RESULTS
The ODI threshold for PASS was 22, irrespective of the time of follow-up (area under the curve [AUC]: 0.89 [sensitivity {Se}: 78.3%, specificity {Sp}: 82.1%] and AUC: 0.91 [Se: 80.7%, Sp: 85.6] for the 1- and 2-year follow-ups, respectively). Sensitivity analyses showed that the absolute ODI-22 threshold for the two follow-up time-points were robust. A stricter definition of PASS resulted in lower ODI thresholds, varying from 16 (AUC=0.89; Se: 80.2%, Sp: 82.0%) to 18 (AUC=0.90; Se: 82.4%, Sp: 80.4%) depending on the time of follow-up.


CONCLUSIONS
An ODI score ≤22 indicates the achievement of an acceptable symptom state and can hence be used as a criterion of treatment success alongside the commonly used change score measures. At the individual level, the threshold could be used to indicate whether or not a patient with a lumbar spine disorder is a "responder" after elective surgery.
Language
  • English
Open access status
green
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Persistent URL
https://sonar.ch/global/documents/107121
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