Melbourne School of Psychological Sciences - Theses

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Author: Holloway, Edith Eva × Start date: 2014 × Type: PhD thesis × Subject: depression × Subject: quality of life ×

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    Improving depressive symptoms in adults with vision impairment: a trial of evidence-based ‘Problem-Solving Treatment' integrated within low vision rehabilitation services
    Holloway, Edith Eva ( 2017)
    Depression is exceedingly prevalent in people with vision impairment (VI), which further exacerbates vision-related functioning, disability and quality of life when left untreated.1-5 Up to 43% of people with VI experience depressive symptoms,6-11 although only one fifth of those receive psychological intervention.11 12 The main objective of this thesis was to evaluate the feasibility, effectiveness and implementation of evidence-based Problem-Solving Treatment for Primary Care (PST-PC) integrated into low vision rehabilitation (LVR) services. In this model, LVR staff were trained to deliver PST-PC via telephone to adult clients identified as showing depressive symptoms. To achieve the overall study objective, a multi-phase, mixed-methods approach was undertaken. In Phase 1, the evidence-base to support the integration of staff-delivered PST-PC in LVR services was delineated by conducting a review of the literature on depression and VI and a systematic review of the effectiveness of problem-solving interventions in this population. The findings underscored the need for pragmatic trials with longer-term follow-up to better understand the suitability of evidence-based problem-solving interventions delivered in routine LVR practice. In Phase 2, the feasibility, acceptability and preliminary data for the effectiveness of PST-PC was investigated. Fourteen LVR staff were trained to deliver PST-PC following a 2-day training workshop and training cases under psychologist supervision. Training cases were 18 LVR clients who received 6 to 8 sessions of PST-PC and participated in a single-group pre-post intervention study. Post intervention, 67% of client participants demonstrated a clinically significant change (CSC; >5-point reduction on the Patient Health Questionnaire-9 (PHQ-9)) in depressive symptoms. PST-PC was found to be highly acceptable to clients with 83% reporting that they were very satisfied with PST-PC. Concerns were raised by both staff and clients regarding telephone delivery and the client retention rate for PST-PC was low (60% completed <6 sessions). The main objective of Phase 3 was to investigate the clinical and cost-effectiveness of this model using a pragmatic, two-arm randomised controlled trial. Adult LVR clients with depressive symptoms (PHQ-9 score >5) were recruited from 28 LVR centres in Australia and randomised to receive PST-PC plus usual care (N=81) or usual care alone (N=82; referral to a general practitioner). In the intention-to-treat (ITT) analysis of the primary outcome (reduced depressive symptoms at 6 months on the PHQ-9), a large treatment effect was found (Cohen’s d (d) = -0.81, 95% CI -1.15 to -0.46) and 40% of the intervention group achieved a CSC compared to 14% of controls (odds ratio (OR) 5.72, 95% CI 1.61 to 20.36). Treatment effects were not maintained at 12 months in ITT analysis, but a significant group difference was found using the per-protocol sample (completed >4 sessions; d=0.59, 95% CI -1.09 to -0.08). ITT analysis of the secondary outcomes found greater improvements in HRQoL (Assessment of Quality of Life; d=0.39, 95% CI 0.05 to 0.72) and vision-specific distress (Impact of Vision Impairment Questionnaire; d=0.40, 95% CI 0.07 to 0.73) in the intervention group at 6 but not at 12 months. The PST-PC model was cost-effective according to commonly used willingness-to-pay thresholds in Australia (incremental cost effectiveness ratio: AU$40,386 (bootstrapped 95% CI: 20,580 to 355,190) per quality-adjusted life years gained). The aim of Phase 4 was to investigate and explore contextual factors associated with implementation of PST-PC in this setting. Given the low rate of participant retention with PST-PC in the RCT (79% completed <6 sessions), pre-treatment demographic, clinical and psychological predictors associated with early termination were investigated. 81 participants randomised to the intervention arm completed baseline and 6-month follow-up telephone assessments. Early termination was associated with being single (OR=8.77, 95% CI 2.15 to 35.66, p=0.002), having low perceived adequacy of social support (OR=0.48, 95% CI 0.30 to 0.75, p=0.001) and low acceptance of vision loss (OR=0.72, 95% CI 0.54 to 0.96, p=0.027). Staff perspectives on the barriers and facilitators to PST-PC delivery were also explored in Phase 4. Guided by theoretical frameworks that seek to evaluate implementation research,13 14 22 key project staff participated in semi-structured qualitative interviews. Prominent barriers to delivery were a lack of role recognition for PST-PC practitioners (n=32), perceived unmet client expectation with PST-PC (n=28) and dissatisfaction with telephone-delivery (n=27). Facilitating factors included a recognised need for evidence-based psychological services (n=28), clients experiencing benefits in early sessions (n=38) and comprehensive PST-PC training (n=36). In summary, this thesis supports the feasibility, clinical and cost-effectiveness of this integrated model for reducing depressive symptoms experienced by people attending Australian LVR centres. Strategies to improve retention with PST-PC are needed to ensure sufficient numbers achieve longer-term clinical benefit. Future research should also give attention as to whether staff-delivered PST-PC is scalable (or sustainable) and to developing services which are accessible to those who do not utilise LVR services (e.g. collaborative care models).