Newly Published
Perioperative Medicine  |   August 2019
Accuracy of Physical Function Questions to Predict Moderate-Vigorous Physical Activity as Measured by Hip Accelerometry
Author Notes
  • From the Departments of Anesthesia and Critical Care (D.S.R., P.N.) and Public Health Sciences (D.H.), the Sections of Geriatrics and Palliative Medicine (M.H.-S.) and Cardiology (R.P.W.), the Pritzker School of Medicine (A.H.), University of Chicago, Chicago Illinois; and the Department of Physical Therapy, College of Applied Health Sciences, University of Illinois at Chicago, Chicago, Illinois (R.A.).
  • 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 February 11, 2019. Accepted for publication June 17, 2019.
    Submitted for publication February 11, 2019. Accepted for publication June 17, 2019.×
  • Correspondence: Address correspondence to Dr. Rubin: 5841 South Maryland Avenue, MC-4028, Chicago, Illinois 60637. drubin@dacc.uchicago.edu. 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 / Cardiovascular Anesthesia / Endocrine and Metabolic Systems / Quality Improvement
Perioperative Medicine   |   August 2019
Accuracy of Physical Function Questions to Predict Moderate-Vigorous Physical Activity as Measured by Hip Accelerometry
Anesthesiology Newly Published on August 30, 2019. doi:10.1097/ALN.0000000000002911
Anesthesiology Newly Published on August 30, 2019. doi:10.1097/ALN.0000000000002911
Abstract

Editor’s Perspective:

What We Know about This Topic:

  • Functional capacity is thought to be an important part of preoperative assessment, but it is hard to assess without formal testing

  • Standardized physical function questions might identify patients with adequate capacity (greater than or equal to 4 metabolic equivalents)

What This Article Tells Us That Is New:

  • Results from standardized physical function questions and hip accelerometers were compared in 522 participants

  • Physical function questions were sensitive but nonspecific

  • Other approaches to assessing physical functional status should be considered

Background: Functional capacity assessment is a core component of current perioperative cardiovascular evaluation and management guidelines for noncardiac surgery. The authors investigated the ability of standardized physical function questions to predict whether participants engaged in moderate physical activity as measured by hip accelerometers.

Methods: Participant responses to physical functioning questions and whether they engaged in moderate physical activity were extracted from the National Health and Nutrition Examination Survey (2003 to 2004 and 2005 to 2006). Physical activity intensity was measured using hip accelerometers. Adult participants with at least one Revised Cardiac Risk Index condition were included in the analysis. Standardized physical function questions were evaluated using a classification and regression tree analysis. Training and test datasets were randomly generated to create and test the analysis.

Results: Five hundred and twenty-two participants were asked the physical functioning questions and 378 of 522 (72.4%) had a bout of moderate-vigorous activity. Classification and regression tree analysis identified a “no difficulty” response to walking up 10 stairs and the ability to walk two to three blocks as the most sensitive questions to predict the presence of a 2-min bout of moderate activity. Participants with positive responses to both questions had a positive likelihood ratio of 3.7 and a posttest probability greater than 90% of a 2-min bout of moderate-vigorous activity. The sensitivity and specificity of positive responses to physical functioning questions in the pruned tree were 0.97 (95% CI, 0.94 to 0.98) and 0.16 (95% CI, 0.10 to 0.23) for training data, and 0.88 (95% CI, 0.75 to 0.96) and 0.10 (95% CI, 0.00 to 0.45) for the test data. Participants with at least one 2-min bout of moderate activity had a greater percentage of overall daily active time (35.4 ± 0.5 vs. 26.7 ± 1.2; P = 0.001) than those without.

Conclusions: Standardized physical function questions are highly sensitive but poorly specific to identify patients who achieve moderate physical activity. Additional strategies to evaluate functional capacity should be considered.