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

PURPOSE To evaluate the validity of the Incremental Shuttle Walk Test (ISWT) for determining risk stratification in cardiac rehabilitation (CR). METHODS This is a cross-sectional study at a major CR center in a middle-income country. Clinically stable adult cardiac patients underwent an ISWT and an exercise test (ET), wore a pedometer for 7 d, and completed the Godin-Shepherd Leisure-Time Physical Activity Questionnaire. Metabolic equivalents of task (METs) achieved on the ISWT were calculated. RESULTS One hundred fifteen patients were evaluated. The mean ± standard deviation distance on the ISWT was 372.70 ± 128.52 m and METs were 5.03 ± 0.62. The correlation of ISWT distance with ET METs (7.57 ± 2.57), steps/d (4556.71 ± 3280.88), and self-reported exercise (13.08 ± 15.19) was rs = 0.61 (P < .001), rs = 0.37 (P < .001), and rs = 0.20 (P = .031), respectively. Distance on the ISWT accurately predicted METs from the ET (area under the receiver operating characteristic curve = 0.774). The ability to walk ≥410 m on the ISWT predicted, with a specificity of 81.5% and a sensitivity of 65.6%, a functional capacity of ≥7 METs on ET. CONCLUSION The ISWT is an alternative way to evaluate functional capacity in CR and can contribute to the process of identifying patients at low risk for a cardiac event during exercise at moderate intensity.