Study protocol for a randomised placebo-controlled trial of pramipexole in addition to mood stabilisers for patients with treatment resistant bipolar depression (the PAX-BD study)

BACKGROUND

Treatment Resistant Bipolar Depression (TRBD) is a major contributor to the burden of disease associated with Bipolar Disorder (BD). Treatment options for people experiencing bipolar depression are limited to three interventions listed by National Institute for Health and Care: lamotrigine, quetiapine and olanzapine, of which the latter two are often not well tolerated. The majority of depressed people with BD are therefore prescribed antidepressants despite limited efficacy. This demonstrates an unmet need for additional interventions. Pramipexole has been shown to improve mood symptoms in animal models of depression, in people with Parkinson's Disease and two proof of principle trials of pramipexole for people with BD who are currently depressed.

METHODS

The PAX-BD study, funded by the United Kingdom (UK) National Institute for Health Research, aims to extend previous findings by assessing the efficacy, safety and health economic impact of pramipexole in addition to mood stabilisers for patients with TRBD. A randomised, double-blind, placebo controlled design is conducted in a naturalistic UK National Health Service setting. An internal pilot study to examine feasibility and acceptability of the study design is included. Participants with TRBD are screened from National Health Service secondary care services in up to 40 mental health trusts in the UK, with the aim of recruiting approximately 414 participants into a pre-randomisation phase to achieve a target of 290 randomised participants. Primary safety and efficacy measures are at 12 weeks following randomisation, with follow up of participants to 52 weeks. The primary outcome is depressive symptoms as measured by Quick Inventory for Depressive Symptomatology - Self Report. Secondary outcomes include changes in anxiety, manic symptoms, tolerability, acceptability, quality of life and cost-effectiveness. Outcome measures are collected remotely using self-report tools implemented online, and observer-rated assessments conducted via telephone. ANCOVA will be used to examine the difference in rating scale scores between treatment arms, and dependent on compliance in completion of weekly self-report measures. A mixed effects linear regression model may also be used to account for repeated measures.

TRIAL REGISTRATION

ISRCTN72151939. Registered on 28 August 2019, http://www.isrctn.com/ISRCTN72151939 Protocol Version: 04-FEB-2021, Version 9.0.

Integrating connectivity theory within watershed modelling part II: Application and evaluating structural and functional connectivity

Integrating connectivity theory within watershed modelling is one solution to overcome spatial and temporal shortcomings of sediment transport prediction, and Part I and II of these companion papers advance this overall goal. In Part II of these companion papers, we investigate sediment flux via connectivity formula discretized over many catchments and then integrated via sediment routing; and we advance model evaluation technology by using hysteresis of sensor data. Model evaluation with hysteresis indices provides nearly a 100% increase in model statistics. Hysteresis loop evaluation shows a shift from near linear behavior at low to moderate events and then clock-wise loops for larger events indicating the importance of proximal sediment sources. Catchment-scale sediment flux varies as function of the probability of timing and extent of connectivity of an individual catchment. Watershed-scale sediment flux shows self-similarity for the main stem of the river channel as the 181 catchments are integrated moving down gradient. Sediment flux varies from event-to-event as a function of the most sensitive connected pathways, including ephemeral gullies and roadside ditches in this basin. These sensitive pathways contribute disproportionately large amounts to overall sediment yield regardless of the total rainfall depth. Prediction requires the connectivity formula, erosion formula and sediment routing formula; and the probability of connectivity alone was a poor predictor for sediment transport. The result highlights the importance of coupling connectivity simulations with sediment transport formula, and our method provides one such approach.

Integrating connectivity theory within watershed modelling part I: Model formulation and investigating the timing of sediment connectivity

Integrating connectivity theory within watershed modelling is one solution to overcome spatial and temporal shortcomings of sediment transport prediction, and Part I and II of these companion papers advance this overall goal. In Part I of these companion papers, we present the theoretical development of probability of connectivity formula considering connectivity's magnitude, extent, timing and continuity that can be applied to watershed modelling. Model inputs include a high resolution digital elevation model, hydrologic watershed variability, and field connectivity assessments. We use the model to investigate the dependence of the probability of connected timing and spatial connectivity on sediment transport predictors. Results show the spatial patterns of connectivity depend on both structural and functional characteristics of the catchment, such as hillslope gradient, upstream contributing area, soil texture, and stream network configuration (structural) and soil moisture content and runoff generation (functional). Spatial connectivity changes from catchment-to-catchment as a function of soil type and drainage area; and it varies from event-to-event as a function of runoff depth and soil moisture conditions. The most sensitive connected pathways provide the stencil for the probability of connectivity, and pathways connected from smaller hydrologic events are consistently reconnected and built upon during larger hydrologic events. Surprisingly, we find the probability of connected timing only depends on structural characteristics of catchments, which are considered static over the timescales analyzed herein. The timing of connectivity does not statistically depend on functional characteristics, which relaxes the parameterization across events of different magnitudes. This result occurs because the pathway stencil accumulates sediment from adjacent soils as flow intensity increases, but this does not statistically shift the frequency distribution.

International Consortium on the Genetics of Electroconvulsive Therapy and Severe Depressive Disorders (Gen-ECT-ic)

Recent genome-wide association studies have demonstrated that the genetic burden associated with depression correlates with depression severity. Therefore, conducting genetic studies of patients at the most severe end of the depressive disorder spectrum, those with treatment-resistant depression and who are prescribed electroconvulsive therapy (ECT), could lead to a better understanding of the genetic underpinnings of depression. Despite ECT being one of the most effective forms of treatment for severe depressive disorders, it is usually placed at the end of treatment algorithms of current guidelines. This is perhaps because ECT has controlled risk and logistical demands including use of general anaesthesia and muscle relaxants and side-effects such as short-term memory impairment. Better understanding of the genetics and biology of ECT response and of cognitive side-effects could lead to more personalized treatment decisions. To enhance the understanding of the genomics of severe depression and ECT response, researchers and ECT providers from around the world and from various depression or ECT networks, but not limited to, such as the Psychiatric Genomics Consortium, the Clinical Alliance and Research in ECT, and the National Network of Depression Centers have formed the Genetics of ECT International Consortium (Gen-ECT-ic). Gen-ECT-ic will organize the largest clinical and genetic collection to date to study the genomics of severe depressive disorders and response to ECT, aiming for 30,000 patients worldwide using a GWAS approach. At this stage it will be the largest genomic study on treatment response in depression. Retrospective data abstraction and prospective data collection will be facilitated by a uniform data collection approach that is flexible and will incorporate data from many clinical practices. Gen-ECT-ic invites all ECT providers and researchers to join its efforts.

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.

CollAborative care and active surveillance for Screen-Positive EldeRs with subthreshold depression (CASPER): a multicentred randomised controlled trial of clinical effectiveness and cost-effectiveness

BACKGROUND

Efforts to reduce the burden of illness and personal suffering associated with depression in older adults have focused on those with more severe depressive syndromes. Less attention has been paid to those with mild disorders/subthreshold depression, but these patients also suffer significant impairments in their quality of life and level of functioning. There is currently no clear evidence-based guidance regarding treatment for this patient group.

OBJECTIVES

To establish the clinical effectiveness and cost-effectiveness of a low-intensity intervention of collaborative care for primary care older adults who screened positive for subthreshold depression.

DESIGN

A pragmatic, multicentred, two-arm, parallel, individually randomised controlled trial with a qualitative study embedded within the pilot. Randomisation occurred after informed consent and baseline measures were collected.

SETTING

Thirty-two general practitioner (GP) practices in the north of England.

PARTICIPANTS

A total of 705 participants aged ≥ 75 years during the pilot phase and ≥ 65 years during the main trial with subthreshold depression.

INTERVENTIONS

Participants in the intervention group received a low-intensity intervention of collaborative care, which included behavioural activation delivered by a case manager for an average of six sessions over 7-8 weeks, alongside usual GP care. Control-arm participants received only usual GP care.

MAIN OUTCOME MEASURES

The primary outcome measure was a self-reported measure of depression severity, the Patient Health Questionnaire-9 items PHQ-9 score at 4 months post randomisation. Secondary outcome measures included the European Quality of Life-5 Dimensions, Short Form questionnaire-12 items, Patient Health Questionnaire-15 items, Generalised Anxiety Disorder seven-item scale, Connor-Davidson Resilience Scale two-item version, a medication questionnaire and objective data. Participants were followed up for 12 months.

RESULTS

In total, 705 participants were randomised (collaborative care n = 344, usual care n = 361), with 586 participants (83%; collaborative care 76%, usual care 90%) followed up at 4 months and 519 participants (74%; collaborative care 68%, usual care 79%) followed up at 12 months. Attrition was markedly greater in the collaborative care arm. Model estimates at the primary end point of 4 months revealed a statistically significant effect in favour of collaborative care compared with usual care [mean difference 1.31 score points, 95% confidence interval (CI) 0.67 to 1.95 score points; p < 0.001]. The difference equates to a standard effect size of 0.30, for which the trial was powered. Treatment differences measured by the PHQ-9 were maintained at 12 months' follow-up (mean difference 1.33 score points, 95% CI 0.55 to 2.10 score points; p = 0.001). Base-case cost-effectiveness analysis found that the incremental cost-effectiveness ratio was £9633 per quality-adjusted life-year (QALY). On average, participants allocated to collaborative care displayed significantly higher QALYs than those allocated to the control group (annual difference in adjusted QALYs of 0.044, 95% bias-corrected CI 0.015 to 0.072; p = 0.003).

CONCLUSIONS

Collaborative care has been shown to be clinically effective and cost-effective for older adults with subthreshold depression and to reduce the proportion of people who go on to develop case-level depression at 12 months. This intervention could feasibly be delivered in the NHS at an acceptable cost-benefit ratio. Important future work would include investigating the longer-term effect of collaborative care on the CASPER population, which could be conducted by introducing an extension to follow-up, and investigating the impact of collaborative care on managing multimorbidities in people with subthreshold depression.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN02202951.

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. 8. See the NIHR Journals Library website for further project information.

Effect of Collaborative Care vs Usual Care on Depressive Symptoms in Older Adults With Subthreshold Depression: The CASPER Randomized Clinical Trial

IMPORTANCE

There is little evidence to guide management of depressive symptoms in older people.

OBJECTIVE

To evaluate whether a collaborative care intervention can reduce depressive symptoms and prevent more severe depression in older people.

DESIGN, SETTING, AND PARTICIPANTS

Randomized clinical trial conducted from May 24, 2011, to November 14, 2014, in 32 primary care centers in the United Kingdom among 705 participants aged 65 years or older with Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition) subthreshold depression; participants were followed up for 12 months.

INTERVENTIONS

Collaborative care (n=344) was coordinated by a case manager who assessed functional impairments relating to mood symptoms. Participants were offered behavioral activation and completed an average of 6 weekly sessions. The control group received usual primary care (n=361).

MAIN OUTCOMES AND MEASURES

The primary outcome was self-reported depression severity at 4-month follow-up on the 9-item Patient Health Questionnaire (PHQ-9; score range, 0-27). Included among 10 prespecified secondary outcomes were the PHQ-9 score at 12-month follow-up and the proportion meeting criteria for depressive disorder (PHQ-9 score ≥10) at 4- and 12-month follow-up.

RESULTS

The 705 participants were 58% female with a mean age of 77 (SD, 7.1) years. Four-month retention was 83%, with higher loss to follow-up in collaborative care (82/344 [24%]) vs usual care (37/361 [10%]). Collaborative care resulted in lower PHQ-9 scores vs usual care at 4-month follow-up (mean score with collaborative care, 5.36 vs with usual care, 6.67; mean difference, -1.31; 95% CI, -1.95 to -0.67; P < .001). Treatment differences remained at 12 months (mean PHQ-9 score with collaborative care, 5.93 vs with usual care, 7.25; mean difference, -1.33; 95% CI, -2.10 to -0.55). The proportions of participants meeting criteria for depression at 4-month follow-up were 17.2% (45/262) vs 23.5% (76/324), respectively (difference, -6.3% [95% CI, -12.8% to 0.2%]; relative risk, 0.83 [95% CI, 0.61-1.27]; P = .25) and at 12-month follow-up were 15.7% (37/235) vs 27.8% (79/284) (difference, -12.1% [95% CI, -19.1% to -5.1%]; relative risk, 0.65 [95% CI, 0.46-0.91]; P = .01).

CONCLUSIONS AND RELEVANCE

Among older adults with subthreshold depression, collaborative care compared with usual care resulted in a statistically significant difference in depressive symptoms at 4-month follow-up, of uncertain clinical importance. Although differences persisted through 12 months, findings are limited by attrition, and further research is needed to assess longer-term efficacy.

TRIAL REGISTRATION

isrctn.org Identifier: ISRCTN02202951.

A novel antigen is shared by retinal pigment epithelium and pigmented neural crest

Pigment cells in vertebrate embryos are formed in both the central and peripheral nervous system. The neural crest, a largely pluripotent population of precursor cells derived from the embryonic neural tube, gives rise to pigment cells which migrate widely in head and trunk.The retinal pigment epithelium is derived from the optic cup, which arises from ectoderm of the neural tube. We have generated an antibody, ips6, which stains an antigen common to pigment cells of retinal pigment epithelium and neural crest. Ips6 stains retinal pigment epithelium and choroid as well as a subset of crest cells that migrate in pathways typical of melanoblasts. Immunoreactivity is seen first in the eye and later in a subset of migrating crest cells. Crest cells in the amphibian embryo migrate along specific, stereotyped routes; ips6 immunoreactive cells are found in some but not all of these pathways. In older wild-type embryos, cells expressing ips6 appear coincident with pigment-containing cells in the flank, head, eye and embryonic gut. In older animals, staining in the eye extends to the intraretinal segment of optic nerve and interstices between photoreceptors and cells at the retinal periphery. We suggest that the ips6 antibody defines an antigen common to pigment cells of central and peripheral origin.