Walking speed threshold for classifying walking independence in hospitalized older adults

Abstract

Background: Walking speed norms and several risk thresholds for poor health outcomes have been published for community-dwelling older adults. It is unclear whether these values apply to hospitalized older adults.

Objective: The purpose of this study was to determine the in-hospital walking speed threshold that best differentiates walking-independent from walking-dependent older adults.

Design: This was a cross-sectional study.

Methods: This study recruited a convenience sample of 174 ambulatory adults aged 65 years and older who had been admitted to a medical-surgical unit of a university hospital. The participants' mean (SD) age was 75 (7) years. Fifty-nine percent were women, 66% were white, and more than 40% were hospitalized for cardiovascular problems. Usual-pace walking speed was assessed over 2.4 m. Walking independence was assessed through self-report. Several methods were used to determine the threshold speed that best differentiated walking-independent patients from walking-dependent patients. Approaches included a receiver operating characteristic (ROC) curve, sensitivity and specificity, and frequency distributions.

Results: The participants' mean (SD) walking speed was 0.43 (0.23) m/s, and 62% reported walking independence. Nearly 75% of the patients walked more slowly than the lowest community-based risk threshold, yet 90% were discharged home. Overall, cut-point analyses suggested that 0.30 to 0.35 m/s may be a meaningful threshold for maintaining in-hospital walking independence. For simplicity of clinical application, 0.35 m/s was chosen as the optimal cut point for the sample. This threshold yielded a balance between sensitivity and specificity (71% for both). Limitations The limitations of this study were the small size of the convenience sample and the single health outcome measure.

Conclusions: Walking speeds of older adults who are acutely ill are substantially slower than established community-based norms and risk thresholds. The threshold identified, which was approximately 50% lower than the lowest published community-based risk threshold, may serve as an initial risk threshold or target value for maintaining in-hospital walking independence.

Figure 1.

Receiver operating characteristic (ROC) curve of walking speed on walking independence. AUC=area under the curve, CI=confidence interval. Values of 0.36 m/s and 0.29 m/s represent the walking speed cut-points identified via the “closest-to-0,1” and Youden Index criteria, respectively.

Figure 2.

Frequency distributions of walking speed by walking disability category.