Newly Published
Perioperative Medicine  |   March 2020
Defining the Minimal Clinically Important Difference and Patient-acceptable Symptom State Score for Disability Assessment in Surgical Patients
Author Notes
  • From the Department of Anaesthesiology and Perioperative Medicine (M.A.S.) and the Department of Anaesthesiology and Perioperative Medicine (P.S.M.), Alfred Hospital and Monash University, Melbourne, Victoria, Australia; and the School of Public Health and Preventive Medicine, Monash University, Melbourne, Victoria, Australia (J.K.).
  • Supplemental Digital Content is available for this article. Direct URL citations appear in the printed text and are available in both the HTML and PDF versions of this article. Links to the digital files are provided in the HTML text of this article on the Journal’s Web site (www.anesthesiology.org).
    Supplemental Digital Content is available for this article. Direct URL citations appear in the printed text and are available in both the HTML and PDF versions of this article. Links to the digital files are provided in the HTML text of this article on the Journal’s Web site (www.anesthesiology.org).×
  • Submitted for publication April 15, 2019. Accepted for publication February 12, 2020.
    Submitted for publication April 15, 2019. Accepted for publication February 12, 2020.×
  • Correspondence: Address correspondence to Dr. Shulman: Alfred Hospital, Commercial Road, Melbourne, Victoria 3004, Australia. m.shulman@alfred.org.au. Information on purchasing reprints may be found at www.anesthesiology.org or on the masthead page at the beginning of this issue. Anesthesiology’s articles are made freely accessible to all readers, for personal use only, 6 months from the cover date of the issue.
Article Information
Perioperative Medicine / Quality Improvement
Perioperative Medicine   |   March 2020
Defining the Minimal Clinically Important Difference and Patient-acceptable Symptom State Score for Disability Assessment in Surgical Patients
Anesthesiology Newly Published on March 10, 2020. doi:https://doi.org/10.1097/ALN.0000000000003240
Anesthesiology Newly Published on March 10, 2020. doi:https://doi.org/10.1097/ALN.0000000000003240
Abstract

Background: The World Health Organization Disability Assessment Schedule 2.0 has been used to measure postoperative disability in several clinical trials and cohort studies. It is uncertain what the minimal clinically important difference or patient-acceptable symptom state scores are for this scale in patients recovering from surgery.

Methods: The authors analyzed prospectively collected data from three studies that measured disability 3 and 6 months after surgery. Three distribution-based methods (0.3 multiplied by SD, standard error of the measurement, and 5% range) and two anchor-based methods (anchored to two patient-rated health status questions and separately to unplanned hospital readmission) were averaged to estimate the minimal clinically important difference for the World Health Organization Disability Assessment Schedule 2.0 score converted to a percentage scale. Scores consistent with a patient-acceptable symptom state and clinically significant disability were determined by an anchored 75th centile method.

Results: Data from 4,361 patients were analyzed. The average minimal clinically important difference estimate for the World Health Organization Disability Assessment Schedule 2.0 was 5%, with similar estimates in patients with or without preoperative disability. The patient-acceptable symptom state score was 16%, and the score consistent with at least moderate clinically significant disability was 35%. Using these estimates, between baseline and 6 months after surgery, 21% of patients had a significant increase in disability, and 73% achieved a patient-acceptable symptom state.

Conclusions: A change in World Health Organization Disability Assessment Schedule 2.0 score of 5% or more after surgery is consistent with a clinically important change in disability. Patients with a score less than 16% after surgery have an acceptable symptom state and can be considered as disability-free, whereas patients with a score of 35% or more can be considered as having at least moderate clinically significant disability.

Editor’s Perspective:

What We Already Know about This Topic:

  • The World Health Organization Disability Assessment Schedule 2.0 is finding widespread adoption as a patient-centered outcome measure in clinical studies

  • The minimal clinically important difference and patient-acceptable disability score for patients undergoing surgery remain poorly understood

What This Manuscript Tells Us That Is New:

  • Using previously collected data from three studies across 4,361 patients, a 5% change in score after surgery is clinically important

  • Patients with a scaled disability score less than 16% after surgery have an acceptable symptom state and can be considered as disability-free