Balance Confidence Modulates the Association of Gait Speed With Falls in Older Fallers: A Prospective Cohort Study

Objectives: Self-perceived balance confidence (BC) and gait speed influence falls. Whether they modulate each other in fall prediction stays uncertain. This study examined whether and how BC modulated the association between gait speed and falls. Design: Prospective observational cohort study. Setting and Participants: Older adults who were community-dwelling, ≥65 years old, able to walk for 10 meters independently, and had 1 or more falls in the past year were assessed at a research clinic. Methods: Participants were followed up trimonthly for 12 months after the baseline. Optimal cutoff values for gait speed for prospective falls were identified by classification and regression tree analysis. Associations among gait speed, BC, and falls were estimated with negative binomial regression models. Subgroup analyses for high and low BC were performed. Covariates such as basic demographics, generic cognition, fall histories, and other physical functions were adjusted. Results: During the follow-up period, 65 (14%) of the 461 included participants (median age 69.0 ± 10.0 years, range 60–92) reported 83 falls in total. In both the pooled and subgroup analyses for the low- and high-BC groups, the high-speed subgroup (≥1.30 m/s) showed an increased fall risk compared with the moderate-speed subgroup (≥0.81 and <1.30 m/s) [adjusted odds ratio (OR), 1.84–2.37; 95% CI, 1.26–3.09]. A statistically significant linear association between gait speed and falls was shown in the high-BC group. In the low-BC group, a u-shaped association was evident (adjusted OR, 2.19–2.44; 95% CI, 1.73–3.19) with elevated fall risks in both the high- and low-speed subgroups compared with the moderate-speed subgroup (adjusted OR, 1.84–3.29; 95% CI, 1.26–4.60). Conclusions and Implications: BC modulated the association between gait speed and falls. There were linear and nonlinear associations between gait speed and falls in people with high and low BC, respectively. Clinicians and researchers should consider the effects of BC when predicting falls with gait speed.