OBJECTIVE: To examine fall risk trajectories occurring naturally in a sample of individuals with early to middle stage Parkinson's disease (PD).
DESIGN: Fall risk at each six-month assessment was determined using a simple clinical tool based on fall history, freezing of gait and gait speed. Fall risk trajectories over the two-year follow up period were identified using latent class analysis, specifically growth mixture modelling (GMM). SETTING: Not applicable. PARTICIPANTS: 230 community-dwelling PD participants of a longitudinal cohort study who attended at least two of five assessments. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Fall risk trajectory (low, medium or high risk) and stability of fall risk trajectory (stable or fluctuating).
RESULTS: The GMM optimally grouped participants into three fall risk trajectories that closely mirrored baseline fall risk status (p=.001). The high fall risk trajectory was most common (42.6%) and included participants with longer and more severe disease and with higher postural instability and gait disability (PIGD) scores than the low and medium risk trajectories (p<.001). Fluctuating fall risk (posterior probability <0.8 of belonging to any trajectory) was found in only 22.6% of the sample, most commonly among individuals who were transitioning to PIGD predominance.
CONCLUSIONS: Regardless of their baseline characteristics, most participants had clear and stable fall risk trajectories over two years. Further investigation is required to determine whether interventions to improve gait and balance may improve fall risk trajectories in people with PD.