Validity of the Incremental Shuttle Walk Test to Assess Exercise Safety Initiating Cardiac Rehabilitation in Low-Resource Countries

Abstract

Purpose: To evaluate the validity of the Incremental Shuttle Walk Test (ISWT) to inform risk stratification in cardiac rehabilitation. Methods: This is a cross-sectional study at the major Cardiac Rehabilitation (CR) center in a middle-income country. Clinically-stable adult cardiac patients underwent an Incremental Shuttle Walk Test (ISWT) and a stress test (ST), wore a pedometer for 7 days and completed the Godin-Shepherd Leisure -Time Physical Activity Questionnaire. Metabolic equivalents of task (METs) achieved on the ISWT were calculated. Results: 115 patients were evaluated. The mean distance on the ISWT was 372.70±128.52 meters (standard deviation; mean METs=5.03±0.62). The correlation of the ISWT distance with ST METs (7.57±2.57), steps/day (4556.71±3280.88) and self-reported exercise (13.08±15.19 was rs=0.61 (p<0.001), rs=0.37 (p<0.001), and rs=0.20 (p=0.031), respectively. Distance on the ISWT accurately predicted METs from the ST (area under the received operation curve=0.774). The ability to walk ≥410 meters on the ISWT predicted, with a specificity of 81.5% and a sensitivity of 65.6%, a functional capacity of ≥7 METs on ST. Conclusion: The ISWT is an alternative way to evaluate functional capacity and can contribute to the process of identifying patients at low-risk for a cardiac event during exercise at moderate-intensity.