Preventing Falls in People Aged Over 75 at High Risk of Falling Through Specific Rehabilitation Involving Walking Backwards (PCRetro)

Justification: Falls are the leading cause of unintentional injuries in the population aged over 75 years in France. Backward walking training has so far been scarcely studied but appears to show promising results compared with conventional rehabilitation across multiple domains. It improves functional capacity, lower limb muscle strength, gait parameters, balance, and stability, all of which are key factors in reducing fall risk. Therefore, we hypothesize that a post-fall rehabilitation program incorporating backward walking sessions may reduce the incidence of falls over one year in high fallrisk risk patients aged over 75 years, compared with a standard rehabilitation program.

Primary objective: The primary objective of the study is to assess the impact of backward walking sessions on the incidence of falls at 1 year in patients aged over 75 years at high risk of falling and managed in a geriatric day hospital, compared with usual care in a geriatric day hospital.

Secondary objectives: The secondary objectives are to assess the effects of backward walking intervention, compared with usual care, on physical and psychological performance as balance, gait speed, functional mobility, fear of falling, and on the occurrence of falls and serious events (time to first fall, all-cause and fall-related hospitalizations, mortality). It also aims to evaluate medium- and long-term quality of life, functional independence, and all-cause hospitalizations, as well as the safety, acceptability, and feasibility of the intervention for patients and the day hospital team.

Settings: The sample size calculation was performed to detect a 35% reduction in the annual incidence rate of falls, assuming a control-group incidence of 1.4-3.6 falls per person-year and accounting for an anticipated 10% loss to follow-up. A total of 300 patients are expected to be enrolled over an 18 month inclusion period, with each patient followed for 12 months. Eleven geriatric centers will participate in the trial.

Experimental design: The PCRetro trial is an open-label, multicenter, randomized controlled, parallel-group clinical trial conducted in a geriatric day hospital rehabilitation setting. The study procedures are as follows: during the geriatric day hospital visit, the investigator will propose participation in the trial to eligible patients after verifying inclusion and exclusion criteria, and will subsequently obtain written informed consent. Patients will then be randomized to the control or intervention arm. Patients in the control arm will undergo two rehabilitation sessions per week for 12 weeks according to usual care. Patients in the intervention arm will undergo two rehabilitation sessions per week for 12 weeks according to usual care, combined with backward walking sessions over 5 weeks. In the intervention arm, backward walking will not increase the overall rehabilitation time but will replace part of usual care in order to achieve two effective 10-minute backward walking sessions per week. Patients will be followed in the same way regardless of their randomization arm, with a medical visit at week 5 and at month 6, and a monthly telephone call by a clinical research assistant blinded to the randomization allocation.

Practical procedures: A screening visit will first be conducted, during which clear and appropriate information about the study will be provided to the patient. This will be followed by an inclusion medical visit, during which written informed consent will be obtained, randomization will be performed, and clinical data as well as routine care data and additional data specific to the PCRetro study will be collected. Patients will then undergo rehabilitation either in the control group, receiving usual care in a geriatric day hospital, or in the intervention group, in which two backward walking activities per week will be integrated over a 5 week period in the usual care. Follow-up medical visits will be scheduled at week 5 and at month 6, during which routine care and additional PCRetro study data will again be collected. The occurrence of falls and intercurrent events will be monitored over 12 months through monthly telephone calls made by a clinical research technician. For 10 patients in the intervention group, a semi-structured interview will also be conducted during the week 5 visit. 2 focus groups will be held with 2 randomly selected centers to identify barriers and facilitators to the implementation of backward walking sessions.

Expected benefits: The primary anticipated benefit is a long-term reduction in the incidence of falls. In the short term, neuromuscular and postural improvements are expected, including increased lower limb muscle strength and better static and dynamic balance, which may translate into higher gait speed, improved functional mobility, and possibly reduced fear of falling. In the medium term, a potential decrease in hospitalization and mortality rates is anticipated. In the long term, these benefits could have a significant positive impact on the quality of life of patients and their caregivers.

Expected risks: No serious adverse events have been reported in studies of backward walking to date. Rare cases of increased joint pain, muscle soreness, and heightened fatigue have been described.

Statistical analysis: It will be conducted under the intention-to-treat principle, with data described and stratified by trial arm using appropriate descriptive statistics. The primary outcome will be analyzed using a Poisson model, with prespecified sensitivity analyses, including adjusted and per-protocol analyses based on a priori defined confounders identified via a Directed Acyclic Graph. Binary secondary outcomes will be summarized as odds ratios with 95% confidence intervals, while continuous secondary outcomes will be analyzed using parametric or non-parametric tests as appropriate. Time-to-event endpoints will be examined using Kaplan-Meier curves and Cox proportional hazards models, with results expressed as hazard ratios and 95% confidence intervals. Missing data will be handled in line with current recommendations and the predefined estimand framework. Qualitative data from focus groups and semi-structured interviews will be analyzed independently by two researchers using a Grounded Theory-inspired approach and interpreted within the Normalization Process Theory framework.