Effectiveness of a Collaborative Stepped-care Intervention for Adults Aged 45 and Above With Subthreshold Depressive Symptoms in the Primary Care Setting in Hong Kong

Depression is among the most prevalent mental health conditions globally and contributes substantially to the global burden of disease. In adults, depression is highly comorbid not only with other mental health conditions (e.g., anxiety) but also physical diseases.

Since 2016, the research team has developed a collaborative stepped-care model for older people at-risk of or with depression in Hong Kong through the Jockey Club Holistic Support Project for Elderly Mental Wellness (JC JoyAge) (Clinical Trials Identifier: NCT03593889); the effectiveness and cost-effectiveness of which has been demonstrated, thereby leading to its implementation in social care settings across all 18 districts of Hong Kong.

To further improve the accessibility and availability of mental health services in the community and to reduce the burden associated with depression and related conditions, the JoyAge collaborative stepped-care intervention (cognitive behavioural therapy-based) will be expanded to target adults aged 45 years and above at the district-based primary care setting. This study thus sought to evaluate the effectiveness of this expanded intervention model.

Objective: To examine the effectiveness of the collaborative stepped-care intervention for adults with subthreshold depressive symptoms, as compared with propensity score-matched controls, in reducing depressive symptoms (primary outcome) both post-intervention (T1) and for up to 3 months of follow-up (T2). Secondary outcomes of the study include reduced anxiety symptoms, reduced loneliness, reduced rumination, improved social support, improved health-related quality of life, as well as improved quality-adjusted life years, and reduced healthcare service utilisation.

Design: While a randomised controlled trial would be ideal, such a study design was not possible in our current study context given pragmatic reasons. A quasi-experimental randomised controlled trial involving an (i) intervention arm and (ii) control arm will therefore be adopted. A targeted sample of 352 participants will be recruited (n = 176 per arm). To more rigorously account for potential differences in the sample characteristics of the two arms, propensity-score matching will be applied. After the pre-intervention or baseline (T0), assessments will be conducted at two follow-up time points: post-intervention (9-month post-baseline in the active control group, which is aligned with the median service duration in the intervention arm; T1), and 3-month post-intervention (12-month post-baseline in the active control group; T2).