Estimating dose-response effects in psychological treatment trials: the role of instrumental variables

Estimating drug concentration-response relationships by applying causal inference methods for continuous point exposures and time-to-event outcomes

In clinical development, it is useful to characterize the causal relationship between individual drug concentrations and clinical outcomes in large phase III trials of new therapeutic agents because it can provide insights on whether increasing the currently administered drug dose may lead to better outcomes. However, estimating causal effects of drug concentration is complicated by the fact that drug concentration is a continuous measure and it is usually influenced by patient-level prognostic characteristics such as body weight and sex. In this article, we compare two approaches to estimate causal effects of continuous point exposures on time-to-event outcomes: (a) outcome regression (OR) and (b) weighting. In particular, we make the first direct comparison of the balancing weights, inverse probability weighting and OR methods for estimating the effects of continuous exposures on time-to-event outcomes in simulations and demonstrate that these methods can exhibit markedly different behaviours that subsequently lead to a change in the conclusions. To improve weighted exposure effect estimators, we also propose a new simple-to-apply diagnostic to detect when such estimators might be subject to severe bias, and demonstrate its effectiveness in simulations. Finally, we apply these methods to an example of multiple sclerosis drug development by providing causal effect estimates of average ocrelizumab concentrations on time-to-event disability progression outcomes.

Feasibility, Acceptability, and Preliminary Efficacy of a Positive Affect Skills Intervention for Adults With Fibromyalgia

Background and Objectives

To examine the feasibility, acceptability, and preliminary efficacy of a positive affect skills intervention for middle-aged and older adults with fibromyalgia syndrome (FMS).

Research Design and Methods

Ninety-five participants with FMS aged 50 and older (94% female) were randomized to 1 of 2 conditions: (a) Lessons in Affect Regulation to Keep Stress and Pain UndeR control (LARKSPUR; n = 49) or (b) emotion reporting/control (n = 46). LARKSPUR included 5 weeks of skill training that targeted 8 skills to help foster positive affect, including (a) noticing positive events, (b) savoring positive events, (c) identifying personal strengths, (d) behavioral activation to set and work toward attainable goals, (e) mindfulness, (f) positive reappraisal, (g) gratitude, and (h) acts of kindness. Outcome data were collected via online surveys at baseline, postintervention, and 1-month follow-up.

Results

Completion rates (88%) and satisfaction ratings (10-point scale) were high (LARKSPUR: M = 9.14, standard deviation (SD) = 1.49; control: M = 8.59, SD = 1.97). Improvements were greater in LARKSPUR participants compared with control participants on measures of positive affect (Cohen's d = 0.19 [0.15, 0.24]), negative affect (Cohen's d = -0.07 [-0.11, -0.02]), and pain catastrophizing (Cohen's d = -0.14 [-0.23, -0.05]). Improvements in positive affect (Cohen's d = 0.17 [0.13, 0.22]) and negative affect (Cohen's d = -0.11 [-0.15, -0.06]) were maintained at 1-month follow-up. Dose-response analyses indicated that intervention engagement significantly predicted pre-to-post and post-to-follow-up reductions in pain catastrophizing.

Discussion and Implications

The current preliminary findings add to existing literature and highlight the specific potential of internet-delivered positive affect skills programs for adults with FMS.

Clinical Trial Registration

NCT04869345.

Study protocol: BRInging the Diabetes prevention program to GEriatric Populations

In the Diabetes Prevention Program (DPP) randomized, controlled clinical trial, participants who were  ≥ 60 years of age in the intensive lifestyle (diet and physical activity) intervention had a 71% reduction in incident diabetes over the 3-year trial. However, few of the 26.4 million American adults age ≥65 years with prediabetes are participating in the National DPP. The BRInging the Diabetes prevention program to GEriatric Populations (BRIDGE) randomized trial compares an in-person DPP program Tailored for Older AdulTs (DPP-TOAT) to a DPP-TOAT delivered via group virtual sessions (V-DPP-TOAT) in a randomized, controlled trial design (N = 230). Eligible patients are recruited through electronic health records (EHRs) and randomized to the DPP-TOAT or V-DPP-TOAT arm. The primary effectiveness outcome is 6-month weight loss and the primary implementation outcome is intervention session attendance with a non-inferiority design. Findings will inform best practices in the delivery of an evidence-based intervention.

Shoes for self-managing chronic hip Pain: the SCHIPP randomized clinical trial protocol

BACKGROUND

Chronic hip pain is common and disabling and is largely due to osteoarthritis (OA). Self-management is recommended by international OA clinical guidelines yet there are few effective treatment options. Footwear has been suggested as a self-management approach, given that foot motion influences hip forces. Currently, guidelines advocate 'stable supportive' shoes for people with OA, however this is based solely on expert opinion given no research has investigated whether these shoes are effective at reducing symptoms in people with OA-related chronic hip pain. Therefore, this randomized controlled trial (RCT) aims to determine if stable supportive footwear reduces hip pain during walking compared to flat flexible footwear in people with chronic hip pain consistent with OA.

METHODS

This trial is a 6-month, participant- and assessor-blinded, pragmatic, comparative effectiveness, superiority RCT conducted in Melbourne, Australia. We are recruiting 120 participants aged over 45 years with chronic hip pain consistent with OA from the community. Following baseline assessment, participants are randomized to receive either i) stable supportive shoes or ii) flat flexible shoes. Participants are permitted to choose two different pairs of shoes in their allocated group from a range of options that match prespecified shoe classification criteria. They are advised to wear either pair of study shoes daily for a minimum of 6 hours each day for 6 months. The primary outcome is the 6-month change in average hip pain on walking in the last week. Secondary outcomes include changes in other measures of hip pain, symptoms, function in daily living and sports and recreation, hip-related quality of life, pain at other sites, adverse events, and physical activity. Other measures include co-intervention use, adherence, shoe comfort, descriptive characteristics, footwear characteristics, and objective foot measures.

DISCUSSION

This RCT will determine whether stable supportive shoes reduce hip pain during walking more than flat flexible shoes in people with chronic hip pain. Outcomes will help to inform footwear recommendations in international clinical guidelines for OA-related chronic hip pain, which to date have been based solely on expert opinion because of an absence of RCTs.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry reference: ACTRN12621001532897.

Effect of motion control versus neutral walking footwear on pain associated with lateral tibiofemoral joint osteoarthritis: a comparative effectiveness randomised clinical trial

OBJECTIVES

To determine if motion control walking shoes are superior to neutral walking shoes in reducing knee pain on walking in people with lateral knee osteoarthritis (OA).

DESIGN

Participant-blinded and assessor-blinded, comparative effectiveness, superiority randomised controlled trial.

SETTING

Melbourne, Australia.

PARTICIPANTS

People with symptomatic radiographic lateral tibiofemoral OA from the community and our volunteer database.

INTERVENTION

Participants were randomised to receive either motion control or neutral shoes and advised to wear them >6 hours/day over 6 months.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome was change in average knee pain on walking over the previous week (11-point Numeric Rating Scale (NRS), 0-10) at 6 months. The secondary outcomes included other measures of knee pain, physical function, quality of life, participant-perceived change in pain and function, and physical activity.

RESULTS

We planned to recruit 110 participants (55 per arm) but ceased recruitment at 40 (n=18 motion control shoes, n=22 neutral shoes) due to COVID-19-related impacts. All 40 participants completed 6-month outcomes. There was no evidence that motion control shoes were superior to neutral shoes for the primary outcome of pain (mean between-group difference 0.4 NRS units, 95% CI -1.0 to 1.7) nor for any secondary outcome. The number of participants experiencing any adverse events was similar between groups (motion control shoes: n=5, 28%; neutral shoes: n=4, 18.2%) and were minor.

CONCLUSIONS

Motion control shoes were not superior to neutral shoes in improving knee pain on walking in symptomatic radiographic lateral tibiofemoral joint OA. Further research is needed to identify effective treatments in this important but under-researched knee OA subgroup.

TRIAL REGISTRATION NUMBER

ACTRN12618001864213.

Cognitive remediation for people with bipolar disorder: The contribution of session attendance and therapy components to cognitive and functional outcomes

BACKGROUND

Cognitive remediation (CR) can reduce cognitive and functional difficulties in people with bipolar disorder (BD). To date, there is limited evidence on the contribution of session attendance and therapy components to treatment outcomes. This study explores whether attendance and core CR components contribute to treatment outcomes.

METHODS

This is a secondary analysis using data from a randomized controlled trial comparing CR plus treatment-as-usual (TAU; n = 40) to TAU only (n = 40) in euthymic people with BD. Session attendance was measured by number of sessions and by achieving therapy completion, pre-defined as attending ≥20 sessions. We used instrumental variable analysis to examine the effect of attendance on treatment outcomes. We then considered the association between core therapy components (i.e., massed practice, errorless learning, strategy use, therapist contact) and post-treatment outcome changes using correlation.

RESULTS

The CR group improved significantly in measure of global cognition, psychosocial functioning, and goal attainment. Therapy recipients attended 27.1 sessions on average, with 32 (80%) completing the minimum number of 20 sessions. Attending more sessions and achieving therapy completion were associated with improved treatment outcomes, but this relationship was not significant within the subgroup of CR completers. Improvement in psychosocial functioning was associated with therapist contact and goal attainment with selecting useful strategies during therapy.

CONCLUSIONS

Our findings highlight the relevance of session attendance, specifically the importance of achieving a minimum threshold of CR sessions, for outcome improvement. Strategy use and therapist contact might facilitate improvements in psychosocial functioning and personal recovery goals.

Effect of foot orthoses vs sham insoles on first metatarsophalangeal joint osteoarthritis symptoms: a randomized controlled trial

OBJECTIVES

To compare contoured foot orthoses to sham flat insoles for first MTP joint OA walking pain.

DESIGN

This was a participant- and assessor-blinded, sham-controlled, multi-centre randomized clinical trial set in community-based private practices. Eighty-eight adults aged ≥45 years with symptomatic radiographic first MTP joint OA were randomized to receive contoured foot orthoses (n = 47) or sham flat insoles (n = 41), worn at all times when wearing shoes for 12 weeks. Primary outcome was change in first MTP joint walking pain (11-point numerical rating scale (NRS), 0-10) over 12 weeks. Secondary outcomes included additional first MTP joint and foot pain measures, physical function, quality of life and physical activity. Separate linear regression models for primary and secondary outcomes on treatment group were fit, adjusting for the outcome at baseline and podiatrist. Other measures included adverse events.

RESULTS

88 participants were randomized and 87 (99%) completed the 12-week primary outcome. There was no evidence foot orthoses were superior to sham insoles for reducing pain (mean difference -0.3 NRS units (95% CI -1.2 to 0.6), p = 0.53). Similarly, foot orthoses were not superior to sham on any secondary outcomes. Sensitivity analyses yielded similar results. Adverse events were generally minor and transient.

CONCLUSION

Contoured foot orthoses are no more effective than flat sham insoles for the clinical management of first MTP joint OA. Given the dearth of evidence on treatments for first MTP joint OA, further research is needed to identify effective management approaches for this common and debilitating condition.

Effects of adding aerobic physical activity to strengthening exercise on hip osteoarthritis symptoms: protocol for the PHOENIX randomised controlled trial

BACKGROUND

Hip osteoarthritis (OA) is a leading cause of musculoskeletal pain. Exercise is a core recommended treatment. Most evidence is based on muscle-strengthening exercise, but aerobic physical activity has potential to enhance clinical benefits. The primary aim of this study is to test the hypothesis that adding aerobic physical activity to a muscle strengthening exercise leads to significantly greater reduction in hip pain and improvements in physical function, compared to a lower-limb muscle strengthening exercise program alone at 3 months.

METHODS

This is a superiority, 2-group, parallel randomised controlled trial including 196 people with symptomatic hip OA from the community. Following baseline assessment, participants are randomly allocated to receive either i) aerobic physical activity and muscle strengthening exercise or; ii) muscle strengthening exercise only. Participants in both groups receive 9 consultations with a physiotherapist over 3 months. Both groups receive a progressive muscle strengthening exercise program in addition to advice about OA management. The aerobic physical activity plan includes a prescription of moderate intensity aerobic physical activity with a goal of attaining 150 min per week. Primary outcomes are self-reported hip pain assessed on an 11-point numeric rating scale (0 = 'no pain' and 10 = 'worst pain possible') and self-reported physical function (Western Ontario and McMaster Universities Osteoarthritis Index physical function subscale) at 3 months. Secondary outcomes include other measures of self-reported pain (assessed at 0, 3, 9 months), self-reported physical function (assessed at 0, 3, 9 months), performance-based physical function (assessed at 0, 3 months), joint stiffness (assessed at 0, 3, 9 months), quality of life (assessed at 0, 3, 9 months), muscle strength (assessed at 0, 3 months), and cardiorespiratory fitness (assessed at 0, 3 months). Other measures include adverse events, co-interventions, and adherence. Measures of body composition, serum inflammatory biomarkers, quantitative sensory measures, anxiety, depression, fear of movement and self-efficacy are included to explore causal mechanisms.

DISCUSSION

Findings will assist to provide an evidence-based recommendation regarding the additional effect of aerobic physical activity to lower-limb muscle strengthening on hip OA pain and physical function.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry reference: ACTRN 12619001297112. Registered 20th September 2019.

METHODS - A randomised controlled trial of METhotrexate to treat Hand Osteoarthritis with Synovitis: study protocol for a randomised controlled trial

Background

Hand osteoarthritis is a common and disabling problem without effective therapies. Accumulating evidence suggests the role of local inflammation in causing pain and structural progression in hand osteoarthritis, and hand osteoarthritis with synovitis is a commonly encountered clinical phenotype. Methotrexate is a well-established, low-cost, and effective treatment for inflammatory arthritis with a well-described safety profile. The aim of this multicentre, randomised, double-blind, placebo-controlled trial is to determine whether methotrexate reduces pain over 6 months in patients with hand osteoarthritis and synovitis.

Methods

Ninety-six participants with hand osteoarthritis and synovitis will be recruited through the Osteoarthritis Clinical Trial Network (Melbourne, Hobart, Adelaide, and Perth), and randomly allocated in a 1:1 ratio to receive either methotrexate 20 mg or identical placebo once weekly for 6 months. The primary outcome is pain reduction (assessed by 100 mm visual analogue scale) at 6 months. The secondary outcomes include changes in physical function and quality of life assessed using Functional Index for Hand Osteoarthritis, Australian Canadian Osteoarthritis Hand Index, Health Assessment Questionnaire, Michigan Hand Outcomes Questionnaire, Short-Form-36, tender and swollen joint count, and grip strength, and structural progression assessed using progression of synovitis and bone marrow lesions from magnetic resonance imaging and radiographic progression at 6 months. Adverse events will be recorded. The primary analysis will be by intention to treat, including all participants in their randomised groups.

Discussion

This study will provide high-quality evidence to address whether methotrexate has an effect on reducing pain over 6 months in patients with hand osteoarthritis and synovitis, with major clinical and public health importance. While a positive trial will inform international clinical practice guidelines for the management of hand osteoarthritis, a negative trial would be highly topical and change current trends in clinical practice.

Trial registration

Australian New Zealand Clinical Trials Registry (ANZCTR), ACTRN12617000877381. Registered 15 June 2017, https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=373124

Foot orthoses for first metatarsophalangeal joint osteoarthritis: study protocol for the FORT randomised controlled trial

Background

First metatarsophalangeal (MTP) joint osteoarthritis (OA) is a painful and debilitating condition affecting nearly one in 10 people aged over 50 years. Non-drug, non-surgical treatments are recommended by OA clinical guidelines, yet there have only ever been two randomised controlled trials (RCTs) evaluating such strategies in people with first MTP joint OA. Foot orthoses are a common non-drug, non-surgical strategy used by allied health professionals for people with first MTP joint OA, however, it is unknown whether these devices are effective in improving the symptoms associated with the condition. This clinical trial aimed to determine whether contoured foot orthoses lead to greater reductions in first MTP joint pain on walking compared to sham flat insoles in people with first MTP joint OA.

Methods

The FORT trial (Foot ORthoses for big Toe joint osteoarthritis) is a two-arm participant- and assessor-blinded, multi-site RCT conducted in Melbourne, Sydney, Brisbane and the Gold Coast, Australia. We are recruiting 88 community-dwelling people with symptomatic radiographic first MTP joint OA. Following baseline assessment, participants are randomized to receive either: i) contoured foot orthoses; or ii) sham flat insoles following baseline assessment. Participants have two visits with a study podiatrist where they are provided with their allocated insoles, to be worn daily for 12 weeks at all times when wearing shoes. The primary outcome is self-reported first MTP joint pain on walking (numerical rating scale), assessed at baseline and 12 weeks. Secondary outcomes include additional measures of first MTP joint and foot pain, physical function, quality of life, participant-perceived global ratings of change (pain and function), and level of physical activity.

Discussion

This study will provide novel evidence about whether contoured foot orthoses improve pain and other symptoms compared to sham insoles in people with first MTP joint OA. Outcomes will help to inform clinical guidelines and practice about the use of foot orthoses for managing symptoms in this under-researched group of people with OA.

Trial registration

Prospectively registered with the Australian New Zealand Clinical Trials Registry (reference: ACTRN12619000926134) on 3/07/2019.

Estimating causal effects of internet interventions in the context of nonadherence

A substantial proportion of participants who are offered internet-based psychological treatments in randomized trials do not adhere and may therefore not receive treatment. Despite the availability of justified statistical methods for causal inference in such situations, researchers often rely on analytical strategies that either ignore adherence altogether or fail to provide causal estimands. The objective of this paper is to provide a gentle nontechnical introduction to complier average causal effect (CACE) analysis, which, under clear assumptions, can provide a causal estimate of the effect of treatment for a subsample of compliers. The article begins with a brief review of the potential outcome model for causal inference. After clarifying assumptions and model specifications for CACE in the latent variable framework, data from a previously published trial of an internet-based psychological treatment for irritable bowel syndrome are used to demonstrate CACE-analysis. Several model extensions are then briefly reviewed. The paper offers practical recommendations on how to analyze randomized trials of internet interventions in the context of nonadherence. It is argued that CACE-analysis, whenever it is considered appropriate, should be carried out as a complement to the standard intention-to-treat analysis and that the format of internet-based treatments is particularly well suited to such an analytical approach.

Footwear for osteoarthritis of the lateral knee: protocol for the FOLK randomised controlled trial

BACKGROUND

Structural features of lateral tibiofemoral (TF) joint osteoarthritis (OA) occur in up to half of all people with knee OA, and co-existing lateral TF OA is associated with worse knee pain in people with mixed compartmental knee OA. Clinical guidelines for management of knee OA advocate advice about appropriate footwear, yet there is no research evaluating which types of footwear are best for managing pain associated with lateral TF OA. Biomechanical evidence suggests that "motion-control" footwear, which possess midsoles that are stiffer medially compared to laterally, may shift load away from the lateral compartment of the knee and thus may reduce knee pain associated with lateral TF OA. The primary aim of this study is to compare the effects of motion-control shoes to neutral shoes on knee pain in people with predominantly lateral TF OA.

METHODS

This will be an assessor- and participant-blinded, two-arm, comparative effectiveness randomized controlled trial (RCT) conducted in Melbourne, Australia. We will recruit a minimum of 92 people with painful lateral TF OA from the community. Participants will be randomly allocated to receive either motion-control shoes or neutral shoes and will be instructed to wear their allocated shoes for a minimum of 6 h per day for 6 months. The primary outcome is change in self-reported knee pain on walking, measured using a numerical rating scale, assessed at baseline and 6 months. Secondary outcomes include other measures of knee pain, physical function, quality of life, participant-perceived change in pain and function, and physical activity levels.

DISCUSSION

This study will compare the efficacy of motion-control shoes to neutral shoes for people with painful lateral TF OA. Findings will be the first to provide evidence of the effects of footwear on knee pain in this important subgroup of people with knee OA and allow clinicians to provide accurate advice about the most appropriate footwear for managing pain associated with lateral TF OA.

TRIAL REGISTRATION

This trial has been prospectively registered by the Australian New Zealand Clinical Trials Registry on 15/11/2018 (reference: ACTRN12618001864213).

Guided web-based treatment program for reducing cannabis use: a randomized controlled trial

Background

The aim of this study was to investigate the effects of a web-based treatment program with therapist guidance for adults and adolescents with regular cannabis use from the general population.

Methods

A double blinded randomized controlled trial with a parallel group design was conducted (intervention group n = 151, wait-list control group n = 152). Follow-up 12 weeks from treatment commencement of a 13-module intervention. The primary outcome was frequency of cannabis use. Time by group interaction effects were modeled using generalized estimated equations and the instrumental variable approach was used to estimate the effect of intervention adherence.

Results

At follow-up, the intention to treat (ITT) analyses did not show any significant time by group effects. A significant association between intervention adherence and scores on the cannabis abuse screening test (CAST) was found. Secondary analysis excluding participants who had received other professional help revealed time by group effects for secondary outcomes gram cannabis consumed past week, number of dependency criteria and CAST score. Due to methodological limitations, these latter results should be interpreted with caution.

Conclusions

In this study we did not find a web-based treatment program with therapist guidance to be more effective than a waiting-list in reducing frequency of cannabis use.

Trial registration The trial was pre-registered at ClinicalTrials.gov (NCT02408640) April 3, 2015

Estimating dose-response for time to remission with instrumental variable adjustment: the obscuring effects of drug titration in Genome Based Therapeutic Drugs for Depression Trial (GENDEP): clinical trial data

Background

Threshold regression, in which time to remission is modelled as a stochastic drift towards a boundary, is an alternative to the proportional hazards survival model and has a clear conceptual mechanism for examining the effects of drug dose. However, for both threshold regression and proportional hazard models, when dose titration occurs during treatment, the estimated causal effect of dose can be biased by confounding. An instrumental variable analysis can be used to minimise such bias.

Method

Weekly antidepressant dose was measured in 380 men and women with major depression treated with escitalopram or nortriptyline for 12 weeks as part of the Genome Based Therapeutic Drugs for Depression (GENDEP) study. The averaged dose relative to maximum prescribing dose was calculated from the 12 trial weeks and tested for association with time to depression remission. We combined the instrumental variable approach, utilising randomised treatment as an instrument, with threshold regression and proportional hazard survival models.

Results

The threshold model was constructed with two linear predictors. In the naïve models, averaged daily dose was not associated with reduced time to remission. By contrast, the instrumental variable analyses showed a clear and significant relationship between increased dose and faster time to remission, threshold regression (velocity estimate: 0.878, 95% confidence interval [CI]: 0.152–1.603) and proportional hazards (log hazards ratio: 3.012, 95% CI: 0.086–5.938).

Conclusions

We demonstrate, using the GENDEP trial, the benefits of these analyses to estimate causal parameters rather than those that estimate associations. The results for the trial dataset show the link between antidepressant dose and time to depression remission. The threshold regression model more clearly distinguishes the factors associated with initial severity from those influencing treatment effect. Additionally, applying the instrumental variable estimator provides a more plausible causal estimate of drug dose on treatment effect. This validity of these results is subject to meeting the assumptions of instrumental variable analyses.

Trial registration

EudraCT, 2004–001723-38; ISRCTN, 03693000. Registered on 27 September 2007.

Does telephone-delivered exercise advice and support by physiotherapists improve pain and/or function in people with knee osteoarthritis? Telecare randomised controlled trial

Objective

Evaluate a physiotherapist-led telephone-delivered exercise advice and support intervention for people with knee osteoarthritis.

Methods

Participant-blinded, assessor-blinded randomised controlled trial. 175 people were randomly allocated to (1) existing telephone service (≥1 nurse consultation for self-management advice) or (2) exercise advice and support (5–10 consultations with a physiotherapist trained in behaviour change for a personalised strengthening and physical activity programme) plus the existing service. Primary outcomes were overall knee pain (Numerical Rating Scale, range 0–10) and physical function (Western Ontario and McMaster Universities Osteoarthritis Index, range 0–68) at 6 months. Secondary outcomes, cost-effectiveness and 12-month follow-up were included.

Results

165 (94%) and 158 (90%) participants were retained at 6 and 12 months, respectively. At 6 months, exercise advice and support resulted in greater improvement in function (mean difference 4.7 (95% CI 1.0 to 8.4)), but not overall pain (0.7, 0.0 to 1.4). Eight of 14 secondary outcomes favoured exercise advice and support at 6 months, including pain on daily activities, walking pain, pain self-efficacy, global improvements across multiple domains (overall improvement, improved pain, improved function and improved physical activity) and satisfaction. By 12 months, most outcomes were similar between groups. Exercise advice and support cost $A514/participant and did not save other health service resources.

Conclusion

Telephone-delivered physiotherapist-led exercise advice and support modestly improved physical function but not the co-primary outcome of knee pain at 6 months. Functional benefits were not sustained at 12 months. The clinical significance of this effect is uncertain.

Trial registration number

Australian New Zealand Clinical Trials Registry (#12616000054415).

Effect of cane use on bone marrow lesion volume in people with medial tibiofemoral knee osteoarthritis: randomized clinical trial

OBJECTIVE

To evaluate effects of daily cane use for 3 months on medial tibiofemoral bone marrow lesion (BML) volumes in people with medial tibiofemoral osteoarthritis (OA).

DESIGN

In this randomized controlled trial (RCT), 79 participants with medial tibiofemoral OA were randomized to either a cane group (using a cane whenever walking) or control group (not using any gait aid) for 3 months. The cane group received a single training session by a physiotherapist, using a biofeedback cane to teach optimal technique and body weight support and motor learning principles to facilitate retention of learning. The primary outcome was change in total medial tibiofemoral BML volume (per unit bone volume) measured from magnetic resonance imaging (MRI) at 3 months. Secondary outcomes were BML volumes (per unit bone volume) of the medial tibia and femur, and patient-reported outcomes of overall knee pain, knee pain on walking, physical function, perceived global symptom changes and health-related quality of life. MRI analyses were performed by a blinded assessor.

RESULTS

Seventy-eight participants (99%) completed the primary outcome. Mean (standard deviation) daily cane use was 2.3 (1.7) hours over 3 months. No evidence of between-group differences was found for change in total medial tibiofemoral BML volume (mean difference: -0.0010 (95% confidence intervals: -0.0022, 0.0003)). Most secondary outcomes showed minimal differences between groups.

CONCLUSION

Daily use of a cane during walking for 3 months aiming to reduce knee joint loading did not change medial tibiofemoral BML volumes compared to no use of gait aids.

CLINICAL TRIAL REGISTRATION

Australian New Zealand Clinical Trial Registry (ACTRN12614000909628).

A nurse-led, preventive, psychological intervention to reduce PTSD symptom severity in critically ill patients: the POPPI feasibility study and cluster RCT

Background

High numbers of patients experience severe acute stress in critical care units. Acute stress has been linked to post-critical care psychological morbidity, including post-traumatic stress disorder (PTSD). Previously, a preventive, complex psychological intervention [Psychological Outcomes following a nurse-led Preventative Psychological Intervention for critically ill patients (POPPI)] was developed by this research team, to be led by nurses, to reduce the development of PTSD symptom severity at 6 months.

Objectives

The objectives were to (1) standardise and refine the POPPI intervention, and, if feasible, (2) evaluate it in a cluster randomised clinical trial (RCT).

Design

Two designs were used – (1) two feasibility studies to test the delivery and acceptability (to patients and staff) of the intervention, education package and support tools, and to test the trial procedures (i.e. recruitment and retention), and (2) a multicentre, parallel-group, cluster RCT with a baseline period and staggered roll-out of the intervention.

Setting

This study was set in NHS adult, general critical care units.

Participants

The participants were adult patients who were > 48 hours in a critical care unit, receiving level 3 care and able to consent.

Interventions

The intervention comprised three elements – (1) creating a therapeutic environment in critical care, (2) three stress support sessions for patients identified as acutely stressed and (3) a relaxation and recovery programme for patients identified as acutely stressed.

Main outcome measures

Primary outcome – patient-reported symptom severity using the PTSD Symptom Scale – Self Report (PSS-SR) questionnaire (to measure clinical effectiveness) and incremental costs, quality-adjusted life-years (QALYs) and net monetary benefit at 6 months (to measure cost-effectiveness). Secondary outcomes – days alive and free from sedation to day 30; duration of critical care unit stay; PSS-SR score of > 18 points; depression, anxiety and health-related quality of life at 6 months; and lifetime cost-effectiveness.

Results

(1) A total of 127 participants were recruited to the intervention feasibility study from two sites and 86 were recruited to the RCT procedures feasibility study from another two sites. The education package, support tools and intervention were refined. (2) A total of 24 sites were randomised to the intervention or control arms. A total of 1458 participants were recruited. Twelve sites delivered the intervention during the intervention period: > 80% of patients received two or more stress support sessions and all 12 sites achieved the target of > 80% of clinical staff completing the POPPI online training. There was, however, variation in delivery across sites. There was little difference between baseline and intervention periods in the development of PTSD symptom severity (measured by mean PSS-SR score) at 6 months for surviving patients in either the intervention or the control group: treatment effect estimate −0.03, 95% confidence interval (CI) −2.58 to 2.52; p = 0.98. On average, the intervention decreased costs and slightly improved QALYs, leading to a positive incremental net benefit at 6 months (£835, 95% CI −£4322 to £5992), but with considerable statistical uncertainty surrounding these results. There were no significant differences between the groups in any of the secondary outcomes or in the prespecified subgroup analyses.

Limitations

There was a risk of bias because different consent processes were used and as a result of the lack of blinding, which was mitigated as far as possible within the study design. The intervention started later than anticipated. Patients were not routinely monitored for delirium.

Conclusions

Among level 3 patients who stayed > 48 hours in critical care, the delivery of a preventive, complex psychological intervention, led by nurses, did not reduce the development of PTSD symptom severity at 6 months, when compared with usual care.

Future work

Prior to development and evaluation of subsequent psychological interventions, there is much to learn from post hoc analyses of the cluster RCT rich quantitative and qualitative data.

Trial registration

This trial is registered as ISRCTN61088114 and ISRCTN53448131.

Funding

This project was funded by the National Institute for Health Research (NIHR) Health Services and Delivery Research programme and will be published in full in Health Services and Delivery Research; Vol. 23, No. 30. See the NIHR Journals Library website for further project information.

Psychological Outcomes following a nurse-led Preventative Psychological Intervention for critically ill patients (POPPI): protocol for a cluster-randomised clinical trial of a complex intervention

INTRODUCTION

Acute psychological stress, as well as unusual experiences including hallucinations and delusions, are common in critical care unit patients and have been linked to post-critical care psychological morbidity such as post-traumatic stress disorder (PTSD), depression and anxiety. Little high-quality research has been conducted to evaluate psychological interventions that could alleviate longer-term psychological morbidity in the critical care unit setting. Our research team developed and piloted a nurse-led psychological intervention, aimed at reducing patient-reported PTSD symptom severity and other adverse psychological outcomes at 6 months, for evaluation in the POPPI trial.

METHODS AND ANALYSIS

This is a multicentre, parallel group, cluster-randomised clinical trial with a staggered roll-out of the intervention. The trial is being carried out at 24 (12 intervention, 12 control) NHS adult, general, critical care units in the UK and is evaluating the clinical effectiveness and cost-effectiveness of a nurse-led preventative psychological intervention in reducing patient-reported PTSD symptom severity and other psychological morbidity at 6 months. All sites deliver usual care for 5 months (baseline period). Intervention group sites are then trained to carry out the POPPI intervention, and transition to delivering the intervention for the rest of the recruitment period. Control group sites deliver usual care for the duration of the recruitment period. The trial also includes a process evaluation conducted independently of the trial team.

ETHICS AND DISSEMINATION

This protocol was reviewed and approved by the National Research Ethics Service South Central - Oxford B Research Ethics Committee (reference: 15/SC/0287). The first patient was recruited in September 2015 and results will be disseminated in 2018. The results will be presented at national and international conferences and published in peer reviewed medical journals.

TRIAL REGISTRATION NUMBER

ISRCTN53448131; Pre-results.

Psychological outcomes following a nurse-led preventative psychological intervention for critically ill patients trial: Statistical and health economic analysis plan

The Psychological Outcomes following a nurse-led Preventative Psychological Intervention for critically ill patients trial is a cluster-randomised controlled trial of the clinical and cost-effectiveness of a complex nurse-led preventative psychological intervention compared with usual care in reducing patient-reported post-traumatic stress disorder symptom severity, and other reported psychological morbidities, at six months among Level 3 (intensive care) patients in adult general critical care units in England, Wales and Northern Ireland. This paper describes the proposed statistical and health economic analyses for the Psychological Outcomes following a nurse-led Preventative Psychological Intervention for critically ill patients trial. It is important to complete and publish this plan before inspecting and locking the trial data to ensure that post hoc and data-derived decisions are avoided. Trial registration: ISRCTN53448131.

Dose-response modeling in mental health using stein-like estimators with instrumental variables

A mental health trial is analyzed using a dose–response model, in which the number of sessions attended by the patients is deemed indicative of the dose of psychotherapeutic treatment. Here, the parameter of interest is the difference in causal treatment effects between the subpopulations that take part in different numbers of therapy sessions. For this data set, interactions between random treatment allocation and prognostic baseline variables provide the requisite instrumental variables. While the corresponding two‐stage least squares (TSLS) estimator tends to have smaller bias than the ordinary least squares (OLS) estimator; the TSLS suffers from larger variance. It is therefore appealing to combine the desirable properties of the OLS and TSLS estimators. Such a trade‐off is achieved through an affine combination of these two estimators, using mean squared error as a criterion. This produces the semi‐parametric Stein‐like (SPSL) estimator as introduced by Judge and Mittelhammer (2004). The SPSL estimator is used in conjunction with multiple imputation with chained equations, to provide an estimator that can exploit all available information. Simulated data are also generated to illustrate the superiority of the SPSL estimator over its OLS and TSLS counterparts. A package entitled SteinIV implementing these methods has been made available through the R platform. © 2017 The Authors. Statistics in Medicine Published by John Wiley & Sons Ltd.

A randomized trial to compare exercise treatment methods for patients after total knee replacement: protocol paper

Background

Although the outcome of total knee replacement (TKR) is favorable, surgery alone fails to resolve the functional limitations and physical inactivity that existed prior to surgery. Exercise is likely the only intervention capable of improving these persistent limitations, but exercises have to be performed with intensity sufficient to promote significant changes, at levels that cannot be tolerated until later stages post TKR. The current evidence is limited regarding the effectiveness of exercise at a later stage post TKR. To that end, this study aims to compare the outcomes of physical function and physical activity between 3 treatment groups: clinic-based individual outpatient rehabilitative exercise during 12 weeks, community-based group exercise classes during 12 weeks, and usual medical care (wait-listed control group). The secondary aim is to identify baseline predictors of functional recovery for the exercise groups.

Methods/Design

This protocol paper describes a comparative effectiveness study, designed as a 3-group single-blind randomized clinical trial. Two hundred and forty older adults who underwent TKR at least 2 months prior will be randomized into one of the three treatment approaches. Data will be collected at baseline, 3 months, and 6 months. The wait-listed control group will be randomized to one of the 2 exercise groups after 6 months of study participation, and will complete a 9-month follow-up. Primary outcome is physical function measured by the Western Ontario and McMaster Universities Osteoarthritis Index Physical Function Subscale (WOMAC-PF). Physical function is also measured by performance-based tests. Secondary outcomes include performance-based tests and physical activity assessed by a patient-reported survey and accelerometry-based physical activity monitors. Exploratory outcomes include adherence, co-interventions, attrition, and adverse events including number of falls. Linear mixed models will be fitted to compare the changes in outcome across groups. Logistic regression will identify patient characteristics that predict functional recovery in the exercise groups. Instrumental variable methods will be used to estimate the efficacy of the interventions in the presence of non-compliance.

Discussion

Results will inform recommendations on exercise programs to improve physical function and activity for patients at the later stage post TKR and help tailor interventions according with patients’ characteristics.

Trial registration

ClinicalTrials.gov Identifier NCT02237911.

Components of therapy as mechanisms of change in cognitive therapy for people at risk of psychosis: analysis of the EDIE-2 trial

BACKGROUND

Research suggests that the way in which cognitive therapy is delivered is an important factor in determining outcomes. We test the hypotheses in which the development of a shared problem list, use of case formulation, homework tasks and active intervention strategies will act as process variables.

METHOD

Presence of these components during therapy is taken from therapist notes. The direct and indirect effect of the intervention is estimated by an instrumental variable analysis.

RESULTS

A significant decrease in the symptom score for case formulation (coefficient = -23, 95% CI -44 to -1.7, P = 0.036) and homework (coefficient = -0.26, 95% CI -0.51 to -0.001, P = 0.049) is found. Improvement with the inclusion of active change strategies is of borderline significance (coefficient = -0.23, 95% CI -0.47 to 0.005, P = 0.056).

CONCLUSIONS

There is a greater treatment effect if formulation and homework are involved in therapy. However, high correlation between components means that these may be indicators of overall treatment fidelity.

Psychosocial therapies for patients with cancer: a current review of interventions using psychoneuroimmunology-based outcome measures

BACKGROUND

As part of a new standard of quality cancer care, the Institute of Medicine has recommended inclusion of therapies that address psychosocial needs of cancer patients. A range of psychosocial therapies for managing acute and chronic stress have been developed for patients with cancer, based on the scientific framework of psychoneuroimmunology (PNI). The current review aimed to identify studies of new and emerging PNI-based psychosocial therapies in patients with cancer that have used neuroendocrine-immune biomarkers as outcomes. Specifically, this review aimed to evaluate studies based on the cancer populations involved, types of psychosocial therapies, and PNI measures employed.

METHOD

Methodology was guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. The PubMed, EMBASE, PsychINFO, CINAHL, and Google Scholar online databases were searched using combinations of keywords obtained from previous reviews of psychosocial interventions. Studies from 2001 to 2012 were included if they ( : ) were published in English, ( : ) used experimental or quasi-experimental designs, ( : ) evaluated psychosocial therapies, ( : ) involved cancer patients, and ( : ) reported results on at least one neuroendocrine or immune outcome measure. The search strategy identified 403 records and 2 stages of screening were used to eliminate irrelevant studies.

RESULT

A total of 24 cancer-specific studies of psychosocial therapies that used PNI-based outcome measures were included in this review. Most studies included early-stage breast cancer patients, and 2 major types of therapies emerged, cognitive-behavioral therapies and complementary medical therapies. Durations of interventions ranged widely, from 1.3 hours over a single week to 27 hours over 18 weeks. Considerable diversity in PNI outcomes made statistical comparisons problematic. Studies of cognitive-behavioral therapies were found to have reported the most success in impacting PNI-based measures, which were typically functional measures of the immune system, for example, cytokines.

CONCLUSION

Several issues related to research methodology are discussed. Most important, studies examining dose-response associations and resource allocation are needed to guide future research. A standardized panel of psychosocial instruments and biomarkers for PNI-based studies would enhance comparability of findings across studies when evaluating this body of research and assist with integrating psychosocial therapies into the standard of cancer care.

Impact of cognitive therapy on internalised stigma in people with at-risk mental states

BACKGROUND

Internalised stigma in young people meeting criteria for at-risk mental states (ARMS) has been highlighted as an important issue, and it has been suggested that provision of cognitive therapy may increase such stigma.

AIMS

To investigate the effects of cognitive therapy on internalised stigma using a secondary analysis of data from the EDIE-2 trial.

METHOD

Participants meeting criteria for ARMS were recruited as part of a multisite randomised controlled trial of cognitive therapy for prevention and amelioration of psychosis. Participants were assessed at baseline and at 6, 12, 18 and 24 months using measures of psychotic experiences, symptoms and internalised stigma.

RESULTS

Negative appraisals of experiences were significantly reduced in the group assigned to cognitive therapy (estimated difference at 12 months was -1.36 (95% CI -2.69 to -0.02), P = 0.047). There was no difference in social acceptability of experiences (estimated difference at 12 months was 0.46, 95% CI -0.05 to 0.98, P = 0.079).

CONCLUSIONS

These findings suggest that, rather than increasing internalised stigma, cognitive therapy decreases negative appraisals of unusual experiences in young people at risk of psychosis; as such, it is a non-stigmatising intervention for this population.

The effects of reducing worry in patients with persecutory delusions: study protocol for a randomized controlled trial

Background

Our approach to advancing the treatment of psychosis is to focus on key single symptoms and develop interventions that target the mechanisms that maintain them. In our theoretical research we have found worry to be an important factor in the development and maintenance of persecutory delusions. Worry brings implausible ideas to mind, keeps them there, and makes the experience distressing. Therefore the aim of the trial is to test the clinical efficacy of a cognitive-behavioral intervention for worry for patients with persecutory delusions and determine how the worry treatment might reduce delusions.

Methods/Design

An explanatory randomized controlled trial - called the Worry Intervention Trial (WIT) - with 150 patients with persecutory delusions will be carried out. Patients will be randomized to the worry intervention in addition to standard care or to standard care. Randomization will be carried out independently, assessments carried out single-blind, and therapy competence and adherence monitored. The study population will be individuals with persecutory delusions and worry in the context of a schizophrenia spectrum diagnosis. They will not have responded adequately to previous treatment. The intervention is a six-session cognitive-behavioral treatment provided over eight weeks. The control condition will be treatment as usual, which is typically antipsychotic medication and regular appointments. The principal hypotheses are that a worry intervention will reduce levels of worry and that it will also reduce the persecutory delusions. Assessments will be carried out at 0 weeks (baseline), 8 weeks (post treatment) and 24 weeks (follow-up). The statistical analysis strategy will follow the intention-to-treat principle and involve the use of linear mixed models to evaluate and estimate the relevant between- and within-subjects effects (allowing for the possibility of missing data). Both traditional regression and newer instrumental variables analyses will examine mediation. The trial is funded by the UK Medical Research Council (MRC)/NHS National Institute of Health Research (NIHR) Efficacy and Mechanism Evaluation (EME) Programme.

Discussion

This will be the first large randomized controlled trial specifically focused upon persecutory delusions. The project will produce a brief, easily administered intervention that can be readily used in mental health services.

Trial registration

Current Controlled Trials ISRCTN23197625

Early detection and intervention evaluation for people at risk of psychosis: multisite randomised controlled trial

OBJECTIVE

To determine whether cognitive therapy is effective in preventing the worsening of emerging psychotic symptoms experienced by help seeking young people deemed to be at risk for serious conditions such as schizophrenia.

DESIGN

Multisite single blind randomised controlled trial.

SETTING

Diverse services at five UK sites.

PARTICIPANTS

288 participants aged 14-35 years (mean 20.74, SD 4.34 years) at high risk of psychosis: 144 were assigned to cognitive therapy plus monitoring of mental state and 144 to monitoring of mental state only. Participants were followed-up for a minimum of 12 months and a maximum of 24 months.

INTERVENTION

Cognitive therapy (up to 26 (mean 9.1) sessions over six months) plus monitoring of mental state compared with monitoring of mental state only.

MAIN OUTCOME MEASURES

Primary outcome was scores on the comprehensive assessment of at risk mental states (CAARMS), which provides a dichotomous transition to psychosis score and ordinal scores for severity of psychotic symptoms and distress. Secondary outcomes included emotional dysfunction and quality of life.

RESULTS

Transition to psychosis based on intention to treat was analysed using discrete time survival models. Overall, the prevalence of transition was lower than expected (23/288; 8%), with no significant difference between the two groups (proportional odds ratio 0.73, 95% confidence interval 0.32 to 1.68). Changes in severity of symptoms and distress, as well as secondary outcomes, were analysed using random effects regression (analysis of covariance) adjusted for site and baseline symptoms. Distress from psychotic symptoms did not differ (estimated difference at 12 months -3.00, 95% confidence interval -6.95 to 0.94) but their severity was significantly reduced in the group assigned to cognitive therapy (estimated between group effect size at 12 months -3.67, -6.71 to -0.64, P=0.018).

CONCLUSIONS

Cognitive therapy plus monitoring did not significantly reduce transition to psychosis or symptom related distress but reduced the severity of psychotic symptoms in young people at high risk. Most participants in both groups improved over time. The results have important implications for the at risk mental state concept.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN56283883.

Allowing for missing outcome data and incomplete uptake of randomised interventions, with application to an Internet-based alcohol trial

Missing outcome data and incomplete uptake of randomised interventions are common problems, which complicate the analysis and interpretation of randomised controlled trials, and are rarely addressed well in practice. To promote the implementation of recent methodological developments, we describe sequences of randomisation-based analyses that can be used to explore both issues. We illustrate these in an Internet-based trial evaluating the use of a new interactive website for those seeking help to reduce their alcohol consumption, in which the primary outcome was available for less than half of the participants and uptake of the intervention was limited.

For missing outcome data, we first employ data on intermediate outcomes and intervention use to make a missing at random assumption more plausible, with analyses based on general estimating equations, mixed models and multiple imputation. We then use data on the ease of obtaining outcome data and sensitivity analyses to explore departures from the missing at random assumption. For incomplete uptake of randomised interventions, we estimate structural mean models by using instrumental variable methods.

In the alcohol trial, there is no evidence of benefit unless rather extreme assumptions are made about the missing data nor an important benefit in more extensive users of the intervention. These findings considerably aid the interpretation of the trial's results. More generally, the analyses proposed are applicable to many trials with missing outcome data or incomplete intervention uptake. To facilitate use by others, Stata code is provided for all methods. Copyright © 2011 John Wiley & Sons, Ltd.

A structural mean model to allow for noncompliance in a randomized trial comparing 2 active treatments

We propose a structural mean modeling approach to obtain compliance-adjusted estimates for treatment effects in a randomized-controlled trial comparing 2 active treatments. The model relates an individual's observed outcome to his or her counterfactual untreated outcome through the observed receipt of active treatments. Our proposed estimation procedure exploits baseline covariates that predict compliance levels on each arm. We give a closed-form estimator which allows for differential and unexplained selectivity (i.e. noncausal compliance-outcome association due to unobserved confounding) as well as a nonparametric error distribution. In a simple linear model for a 2-arm trial, we show that the distinct causal parameters are identified unless covariate-specific expected compliance levels are proportional on both treatment arms. In the latter case, only a linear contrast between the 2 treatment effects is estimable and may well be of key interest. We demonstrate the method in a clinical trial comparing 2 antidepressants.