Depression is a more significant predictor for wellbeing in Inclusion Body Myositis than physical disability.

Objectives: (1) determine if there is a correlation between disability, depression, and wellbeing in people with IBM, (2) determine if disability and depression can predict wellbeing in people with IBM, and (3) identify the prevalence of depression and impaired wellbeing in participants with IBM. Methods: In this cross-sectional study, 101 participants with IBM completed the Neuromuscular Symptom Score (NSS), Personal Wellbeing Index (PWI), and Patient Health Questionnaire-9 (PHQ-9) surveys to serve as surrogate measures of physical disability, wellbeing, and depression respectively. Results: Linear regression identified that PHQ-9 significantly predicts PWI, however NSS does not, with a negative predictive value of depression for wellbeing (-2.7513, p < 0.001) and a positive predictive value of disability for wellbeing (0.0575, p = 0.764). Moderate to severe depression was reported in 78.2% of participants, and all but one participant reported reduced wellbeing. Conclusions: Depression is a more significant predictor of wellbeing than disability in participants diagnosed with IBM. There was a high prevalence of depression and reduced wellbeing in participants, highlighting the importance of assessing these factors to optimise treatment in IBM. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This study did not receive any funding ### 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: HREC of Murdoch University gave ethical approval for this work I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the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 All data produced in the present study are available upon reasonable request to the authors