CollAborative care for Screen-Positive EldeRs with major depression (CASPER plus): a multicentred randomised controlled trial of clinical effectiveness and cost-effectiveness.

BACKGROUND: Depression in older adults is common and is associated with poor quality of life, increased morbidity and early mortality, and increased health and social care use. Collaborative care, a low-intensity intervention for depression that is shown to be effective in working-age adults, has not yet been evaluated in older people with depression who are managed in UK primary care. The CollAborative care for Screen-Positive EldeRs (CASPER) plus trial fills the evidence gap identified by the most recent guidelines on depression management.

OBJECTIVES: To establish the clinical effectiveness and cost-effectiveness of collaborative care for older adults with major depressive disorder in primary care.

DESIGN: A pragmatic, multicentred, two-arm, parallel, individually randomised controlled trial with embedded qualitative study. Participants were automatically randomised by computer, by the York Trials Unit Randomisation Service, on a 1 : 1 basis using simple unstratified randomisation after informed consent and baseline measures were collected. Blinding was not possible.

SETTING: Sixty-nine general practices in the north of England.

PARTICIPANTS: A total of 485 participants aged ≥ 65 years with major depressive disorder.

INTERVENTIONS: A low-intensity intervention of collaborative care, including behavioural activation, delivered by a case manager for an average of six sessions over 7-8 weeks, alongside usual general practitioner (GP) care. The control arm received only usual GP care.

MAIN OUTCOME MEASURES: The primary outcome measure was Patient Health Questionnaire-9 items score at 4 months post randomisation. Secondary outcome measures included depression severity and caseness at 12 and 18 months, the EuroQol-5 Dimensions, Short Form questionnaire-12 items, Patient Health Questionnaire-15 items, Generalised Anxiety Disorder-7 items, Connor-Davidson Resilience Scale-2 items, a medication questionnaire, objective data and adverse events. Participants were followed up at 12 and 18 months.

RESULTS: In total, 485 participants were randomised (collaborative care, n  = 249; usual care, n  = 236), with 390 participants (80%: collaborative care, 75%; usual care, 86%) followed up at 4 months, 358 participants (74%: collaborative care, 70%; usual care, 78%) followed up at 12 months and 344 participants (71%: collaborative care, 67%; usual care, 75%) followed up at 18 months. A total of 415 participants were included in primary analysis (collaborative care, n  = 198; usual care, n  = 217), which revealed a statistically significant effect in favour of collaborative care at the primary end point at 4 months [8.98 vs. 10.90 score points, mean difference 1.92 score points, 95% confidence interval (CI) 0.85 to 2.99 score points; p   <  0.001], equivalent to a standard effect size of 0.34. However, treatment differences were not maintained in the longer term (at 12 months: 0.19 score points, 95% CI -0.92 to 1.29 score points; p  = 0.741; at 18 months: < 0.01 score points, 95% CI -1.12 to 1.12 score points; p  = 0.997). The study recorded details of all serious adverse events (SAEs), which consisted of 'unscheduled hospitalisation', 'other medically important condition' and 'death'. No SAEs were related to the intervention. Collaborative care showed a small but non-significant increase in quality-adjusted life-years (QALYs) over the 18-month period, with a higher cost. Overall, the mean cost per incremental QALY for collaborative care compared with usual care was £26,016; however, for participants attending six or more sessions, collaborative care appears to represent better value for money (£9876/QALY).

LIMITATIONS: Study limitations are identified at different stages: design (blinding unfeasible, potential contamination), process (relatively low overall consent rate, differential attrition/retention rates) and analysis (no baseline health-care resource cost or secondary/social care data).

CONCLUSION: Collaborative care was effective for older people with case-level depression across a range of outcomes in the short term though the reduction in depression severity was not maintained over the longer term of 12 or 18 months. Participants who received six or more sessions of collaborative care did benefit substantially more than those who received fewer treatment sessions but this difference was not statistically significant.

FUTURE WORK RECOMMENDATIONS: Recommendations for future research include investigating the longer-term effect of the intervention. Depression is a recurrent disorder and it would be useful to assess its impact on relapse and the prevention of future case-level depression.

TRIAL REGISTRATION: Current Controlled Trials ISRCTN45842879.

FUNDING: This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment ; Vol. 21, No. 67. See the NIHR Journals Library website for further project information.