A self-help fully automated digital intervention to improve subthreshold depressive symptoms among older adults in a socioeconomically deprived region of Brazil (PRODIGITAL): a pragmatic, two-arm randomised controlled trial

Background: Subthreshold depression is a risk factor for major depression and is associated with increased morbidity and mortality, especially in poorly resourced settings. There is emerging evidence that digital interventions may be effective at improving depressive symptoms in High Income Countries but not Low- and Middle-Income settings. We aimed to evaluate the effectiveness of the Viva Vida digital intervention at improving symptoms of subthreshold depression among older adults in socioeconomically deprived settings in Brazil. Methods: PRODIGITAL was a single blind, two-arm, individually randomised controlled trial conducted in 46 primary care clinics in Guarulhos, Brazil. Individuals aged 60+ years were randomly contacted by phone for a screening assessment. Those who presented with anhedonia and/or depressed mood (Patient Health Questionnaire (PHQ)-2), and who subsequently scored between 5 and 9 on the PHQ-9 were invited to participate. The intervention (Viva Vida) arm received a self-help fully automated programme sent via WhatsApp with no support from healthcare professionals. Forty-eight audio and visual messages based on psychoeducation and behavioural activation approaches were delivered over six weeks. The control arm received a single message with information about depression. The primary outcome was the PHQ-9 at three months follow-up. All primary analyses were performed according to allocated arm with imputed data. The trial is registered with ReBEC, RBR-6c7ghfd. Findings: Participants were recruited between 8 September 2021 and 19 August 2022. Of the 454 participants enrolled, 223 were randomised to the intervention arm and 231 to receive the single message. A total of 385 (84.8%) completed the three-month follow-up assessment; no difference in mean PHQ-9 scores between the arms (adjusted difference: -0.61; 95% CI: -1.76, 0.53; p=0.290) was observed. Interpretation: These results demonstrate that a fully automated digital programme did not help to improve subthreshold depressive symptoms amongst older adults. More research is needed to understand how such interventions can be adapted to reduce depressive symptoms as well as prevent against major depression in low-resourced settings. ### Competing Interest Statement The authors have declared no competing interest. ### Clinical Trial The protocol is registered with Registro Brasileiro de Ensaios Clinicos (ReBEC) (RBR-6c7ghfd) ### Funding Statement This study was funded by the Sao Paulo Research Foundation (process number 2017/50094 2) and the Joint Global Health Trials initiative, jointly funded by the Department of Health and Social Care (DHSC), the Foreign, Commonwealth & Development Office (FCDO), the Medical Research Council (MRC) and Wellcome (process number MR/R006229/1). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: This study was authorised by the Secretaria da Saude do Municipio de Guarulhos and approved by the Ethics Committee of the Hospital das Clinicas da Faculdade de Medicina da Universidade de Sao Paulo HCFMUSP (CAPPesq, CAEE: 32078720.0.0000.0068, first approved on 09 July 2020). The Statistical Analysis Plan version 1.0 was submitted to the Kings College London repository. The trial was registered on 21 October 2021 (submitted on 03 August 2021) at the Registro Brasileiro de Ensaios Clinicos (ReBEC, ensaiosclinicos.gov.br), RBR 6c7ghfd. Recruitment of participants began in September 2021. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Data will be available for reasonable requests from authors approximately one year after publication