The impact of daily step count with mobile health apps on clinical outcomes among general population

Abstract Background/Introduction Numerous studies have investigated the correlation between daily step count and the reduction of all-cause mortality and cardiovascular events. However, the optimal daily step count for the general population remains controversial. Purpose This study aims to assess cardiovascular risk based on individual step counts using a large cohort that includes step count data from mHealth Apps (Kencom), health checkups databases, and Japanese insurance claims databases. Methods We analyzed data from 85,204 users registered with Kencom between January 2016 and September 2021. The mean step count during one year before and after baseline data collection was used to define each individual's step count. We divided participants into low (N=45,539) and high (N=39,665) step count groups based on their mean step counts. Additionally, we categorized users into five groups based on their step counts (<4000; 4000-5999; 6000-7999; 8000-9999; and ≥10000) to evaluate cardiovascular events. The primary outcome was the occurrence of cardiovascular events, including myocardial infarction, stroke, angina pectoris, heart failure, and atrial fibrillation, as classified by the International Classification of Diseases and Related Health Problems, 10th Revision (ICD-10). The cumulative incidence was estimated over 5 years. Results The high step count group was generally younger and predominantly male. No significant differences in cardiovascular risk factors such as hypertension, dyslipidemia, diabetes mellitus, and current smoking status were found between the two groups. Stratifying baseline characteristics by step count revealed significant differences among the five groups, with the exception of sex. The cumulative incidence of cardiovascular events was significantly lower in the high step count group compared to the low step count group (6.5% vs. 7.5%, log-rank P=0.005, Figure 1). After adjusting for confounding factors, the risk reduction of the high step count group remained significant (HR: 0.92, 95% CI: 0.87-0.98, P=0.005). Among the five step count groups, the incidence of primary outcome significantly differed, with only Group 5 (≥10000 steps) showing a significant reduction in the risk of cardiovascular events compared to Group 1 (<4000 steps) after adjustment (HR: 0.87, 95% CI: 0.77-0.99, P=0.03). Subgroup analyses based on sex indicated that the risk reduction was significant in males in Group 5 but not in females. Conclusion The risk of cardiovascular events was higher in the low step count group compared to the high step count group. After adjusting for confounders, only the highest step count group (≥10,000 steps/day) showed a significant reduction in cardiovascular event risk compared to the lowest step count group.