Supplementary Material for: Effects of a Mindfulness-Based Intervention versus Health Self-Management on Subclinical Anxiety in Older Adults with Subjective Cognitive Decline: The SCD-Well Randomized Superiority Trial

Introduction: Older adults experiencing subjective cognitive decline (SCD) have a heightened risk of developing dementia and frequently experience subclinical anxiety, which is itself associated with dementia risk. Objective: To understand whether subclinical anxiety symptoms in SCD can be reduced through behavioral interventions. Methods: SCD-Well is a randomized controlled trial designed to determine whether an 8-week mindfulness-based intervention (caring mindfulness-based approach for seniors; CMBAS) is superior to a structurally matched health self-management program (HSMP) in reducing subclinical anxiety. Participants were recruited from memory clinics at 4 European sites. The primary outcome was change in anxiety symptoms (trait subscale of the State-Trait Anxiety Inventory; trait-STAI) from pre- to postintervention. Secondary outcomes included a change in state anxiety and depression symptoms postintervention and 6 months postrandomization (follow-up). Results: One hundred forty-seven participants (mean [SD] age: 72.7 [6.9] years; 64.6% women; CMBAS, n = 73; HSMP, n = 74) were included in the intention-to-treat analysis. There was no difference in trait-STAI between groups postintervention (adjusted change difference: –1.25 points; 95% CI –4.76 to 2.25) or at follow-up (adjusted change difference: –0.43 points; 95% CI –2.92 to 2.07). Trait-STAI decreased postintervention in both groups (CMBAS: –3.43 points; 95% CI –5.27 to –1.59; HSMP: –2.29 points; 95% CI –4.14 to –0.44) and reductions were maintained at follow-up. No between-group differences were observed for change in state anxiety or depression symptoms. Conclusions: A time-limited mindfulness intervention is not superior to health self-management in reducing subclinical anxiety symptoms in SCD. The sustained reduction observed across both groups suggests that subclinical anxiety symptoms in SCD are modifiable. ClinicalTrials.gov identifier: NCT03005652.