BackgroundThe Otago Exercise Programme is an effective intervention for falls prevention. However, there is limited evidence in relation to studies that compare efficacy for falls prevention when delivered Otago Exercise Programme in a group or individual format in a primary care context.ObjectiveTo compare the Otago Exercise Programme delivered as a group vs. individual format for community dwelling older adults, over a one year period. The hypothesis was that neither format would be inferior to the other.Design:A four-year multicentre, randomized, non-inferiority clinical trial, with two arms- Otago Exercise Programme group training and individual Otago exercise training. Setting(s): 21 primary healthcare centers. Participants: A sample size of 728 participants was established. Participants were aged between 65 and 80 years; living in the community; able to walk independently; and agreed to take part in the study and provided signed informed consent. Intervention: The Otago Exercise Programme was delivered mainly by nurses in primary care, with five face to face sessions, and a reinforcement 6 months later. Participants were encouraged to exercise at home between face to face sessions. Data collection: at baseline and after 6 and 12 months from October 2017 to 2020. Primary outcome: people who reported at least one fall. Secondary outcomes: number of falls, cause of falls, consequences and assistance, adherence and satisfaction. Group allocation was blinded to the researchers involved in analysis. Reporting: Consolidated Standards of Reporting Trials recommendations for the Statement for Randomized Trials of Nonpharmacologic Treatments.ResultsEight hundred twenty-seven participants were randomized (226 were allocated in group training and 272 in individual training). The analysis of the proportion of people who reported at least one fall and number of falls showed no differences between individual and group training. Assessment of the equivalence between the interventions at 12 months showed that the confidence interval for the difference of people who reported at least one fall was found to be within the equivalence limit of 10% considered. However, in those participants with a previous history of falls, group format showed potentially greater benefit. The participants in individual training presented higher scores on the Exercise Adherence Rating Scale test. No differences were found in satisfaction between the groups.ConclusionsThe group Otago Exercise Programme is equivalent to individually delivered Otago Exercise Programme in terms of prevention of falls over a 12-month follow up. Adherence was higher in individual training. Implications: Healthcare professionals could offer either Otago Exercise Programme format dependent on patient preference and be confident that that standardized intervention provides patient benefit.Trial RegistrationClinicalTrials.gov (NCT03320668). Data registration 31/10/2017.