Impact of 12-Minute Walk Test Distance on Mortality in a Group of Phase II Cardiac Rehabilitation Patients

Abstract

ABSTRACT Background To assess aerobic capacity in patients undergoing treatment in a cardiac rehabilitation program (CRP), the 12-minute walk test (12MWT) may be an alternative to cardiopulmonary exercise testing. The 12MWT may be a more appropriate test based on a cardiac rehabilitation (CR) patient’s functional capacity. The objective of this study was to determine the impact of distance walked on a 12MWT on all-cause mortality in patients undergoing treatment in a phase II CRP. Methods A total of 810 phase II CR patients completed the pretreatment and posttreatment 12MWT. Patients were placed into groups based on distance completed using a half-mile (2,640 feet = 804.7 m) as the differential distance. The groups were the remained low group (LG; pre-12MWT and post-12MWT < 2,640 feet), improved group (IG; (pre-12MWT < 2,640 feet and post-12MWT ≥ 2,640 feet), and remained high group (HG; pre-12MWT and post-12MWT ≥ 2,640 feet). Covariates were assessed using Cox regression and Kaplan-Meier curves to assess mortality rates. Results Significant predictor variables of overall mortality included 12MWT distance, age, overweight/obesity, and diabetes. HG had significantly higher survivability than IG and LG. IG had higher survivability than LG, but results were not statistically significant. The 12MWT was a predictor of all-cause mortality when using a distance of 2,640 feet. Improvements in overall mortality related to completing 2,640 feet pre/post-12MWT, with improvement from below 2,640 feet to above 2,640 feet throughout CR, with significant improvements in mortality. Conclusions These results show that the 12MWT is a valid predictor of all-cause mortality in the phase II CR patient population.