Objective To determine the relationship between walking speed (WS) maintained during a 1 km test and its improvement on hospitalisation in cardiac outpatients who were referred to an exercise-based secondary prevention programme.

Methods Hospitalisation was assessed in 1791 patients 3 years after enrolment and related to the WS achieved during a 1 km walk at moderate intensity on a treadmill. Hospitalisation was also assessed during the fourth-to-sixth years as function of improvement in WS in 1111 participants who were re-evaluated 3 years after baseline.

Results Three-year hospitalisation rate across tertiles of baseline WS was 50% for the slow walkers (2.7±0.6 km/hour), 41% for the moderate (4.1±0.3 km/hour) and 25% for the fast walkers (5.2±0.5 km/hour) (p for trend <0.0001), with adjusted HRs (95% CI) of 0.93 (0.74 to 1.17, p=0.53) for intermediate and 0.58 (0.43 to 0.78, p=0.0003) for fast. Every 1 km/hour increase in WS was associated with a 21% reduction in hospitalisation (p<0.0001). Hospitalisation from the fourth-to-sixth years was lower across tertiles of improved WS, with 44% for the low (0.2±0.4 km/hour), 34% for the intermediate (0.8±0.2 km/hour) and 30% for the high tertile (1.6±0.4 km/hour) (p for trend <0.0001). Adjusted HRs were 0.68 (p=0.002) for the intermediate and 0.58 (p<0.0001) for the high tertile. Every 1 km/hour increase in WS was associated with a 35% reduction in hospitalisation (p<0.0001).

Conclusion Improvement in WS is associated with a significant, dose-dependent lower rate of all-cause hospitalisation in cardiac outpatients. WS is a simple, easily applied and clinically useful tool for cardiac patients undergoing secondary prevention.