The development of CHAMP: a checklist for the appraisal of moderators and predictors

Effectiveness and cost-effectiveness of a 12-month automated text message intervention for weight management in postpartum women with overweight or obesity: protocol for the Supporting MumS (SMS) multisite, parallel-group, randomised controlled trial

INTRODUCTION

The reproductive years can increase women's weight-related risk. Evidence for effective postpartum weight management interventions is lacking and engaging women during this life stage is challenging. Following a promising pilot evaluation of the Supporting MumS intervention, we assess if theory-based and bidirectional text messages to support diet and physical activity behaviour change for weight loss and weight loss maintenance, are effective and cost-effective for weight change in postpartum women with overweight or obesity, compared with an active control arm receiving text messages on child health and development.

METHODS AND ANALYSIS

Two-arm, parallel-group, assessor-blind randomised controlled trial with cost-effectiveness and process evaluations. Women (n=888) with body mass index (BMI) ≥25 kg/m2 and within 24 months of giving birth were recruited via community and National Health Service pathways through five UK sites targeting areas of ethnic and socioeconomic diversity. Women were 1:1 randomised to the intervention or active control groups, each receiving automated text messages for 12 months. Data are collected at 0, 6, 12 and 24 months. The primary outcome is weight change at 12 months from baseline, compared between groups. Secondary outcomes include weight change (24 months) and waist circumference (cm), proportional weight gain (>5 kg), BMI (kg/m2), dietary intake, physical activity, infant feeding and mental health (6, 12 and 24 months, respectively). Economic evaluation examines health service usage and personal expenditure, health-related quality of life and capability well-being to assess cost-effectiveness over the trial and modelled lifetime. Cost-utility analysis examines cost per quality-adjusted life-years gained over 24 months. Mixed-method process evaluation explores participants' experiences and contextual factors impacting outcomes and implementation. Stakeholder interviews examine scale-up and implementation.

ETHICS AND DISSEMINATION

Ethical approval was obtained before data collection (West of Scotland Research Ethics Service Research Ethics Committee (REC) 4 22/WS/0003). Results will be published via a range of outputs and audiences.

TRIAL REGISTRATION NUMBER

ISRCTN16299220.

Predictors and moderators of treatment outcome in late-life anxiety: A systematic review

BACKGROUND

The aim of this review was to identify and critically appraise predictors and moderators of outcomes of psychological and pharmacological treatments for late-life anxiety disorders. Their identification may guide the development of personalised treatments for older people with anxiety disorders.

METHODS

Web of Science, PsychINFO, CINAHL, Embase, and Pubmed were searched for studies published up to 12 May 2022. Randomised controlled trials and observational studies reporting treatment predictors and moderators were included. Participants with a diagnosis of any anxiety disorder who were aged over 60 years were included. Treatment outcomes included response, remission, and change in anxiety score.

RESULTS

Thirteen studies met the inclusion criteria. Twenty-three out of 49 predictors or moderators assessed at post-treatment, and 14 out of 33 predictors or moderators assessed at follow-up were statistically significant. Only one predictor, baseline worry severity at post-treatment, was reported in at least three studies. Most studies were rated as having a low risk of bias in at least three areas and satisfied important quality criteria for predictor and moderator analyses.

LIMITATIONS

Samples were predominantly white, female and highly educated, and most studies were secondary analyses.

CONCLUSIONS

There is evidence that baseline worry severity appears to predict treatment outcome in late-life anxiety disorders. However, this was only explored in psychological intervention studies and therefore its predictive ability in pharmacotherapy remains unknown. Future research should explore predictors and moderators in a range of anxiety disorders and design methodologically-strong and adequately-powered studies with the primary aim of assessing predictors of treatment outcomes.

Do imaging findings modify the effect of non-surgical treatment in patients with knee and hip osteoarthritis? A systematic literature review

OBJECTIVES

To review the available evidence on diagnostic imaging findings in knee and hip osteoarthritis (OA) as treatment effect modifiers in non-surgical OA interventions.

METHODS

MEDLINE, Embase and The Cochrane Central Register of Controlled Trials were searched from the earliest records published to 22 March 2022. Studies in knee and hip OA reporting subgroup analyses in randomised controlled trials with imaging findings as potential treatment effect modifiers were included. Studies were critically appraised using the Cochrane risk of bias tool and a subgroup analysis quality assessment.

RESULTS

Of 10 014 titles and abstracts screened, eight studies met the inclusion criteria, six on knee OA and two on hip OA. The studies investigated effect modifiers in exercise therapy, intra-articular injections and unloading shoes. Imaging findings assessed as potential treatment effect modifiers were radiographic OA severity, hip effusion (ultrasound), bone marrow lesions and meniscal pathology (MRI). Two studies fulfilled the methodological quality criteria for assessing effect modification. One reported that radiographic knee OA severity modified the effect of unloading shoes on walking pain. Those with more severe radiographic knee OA had a greater response to shoe inserts. One reported no interaction between radiographic OA severity or joint effusion and the effect of intraarticular injections of corticosteroid or hyaluronic acid in hip OA, indicating no difference in response in people with greater hip joint effusion or radiographic OA severity compared with those with less severe joint disease.

CONCLUSION

Overall, methodological limitations and very few studies do not permit conclusions on diagnostic imaging findings as effect modifiers in non-surgical interventions in knee and hip OA.Radiographic severity of knee OA potentially modifies the effect of unloading shoes.

PROSPERO REGISTRATION NUMBER

CRD42020181934.

Interaction analyses: Enhancing understanding of chronic low back pain

BACKGROUND

Chronic low back pain (CLBP) is complex. Statistical examination of influences of exposures (e.g. characteristics) upon outcomes (e.g. pain) facilitates understanding of complexity and personalized care. Psychological factors may be associated with higher disability following exercise in CLBP. Examining interactions of psychological variables with exercise on disability might further understanding of CLBP.

OBJECTIVES

Secondary analysis of data from a CLBP cohort evaluating interactions between psychological variables and exercise on disability.

DESIGN

Longitudinal cohort study.

METHOD

Variables from a published prognostic model for disability: disability (baseline/one-year follow-up), psychological principal component scores (principal component score two (PC2) - Fear-avoidance beliefs, pain catastrophizing, pain self-efficacy; principal component score three (PC3) - thought suppression, behavioral endurance), exercise (during follow-up), forward-bending time, punishing significant other responses. Differences between exercisers and non-exercisers were assessed using Chi-Squared/Mann-Whitney tests. Multivariable linear regression models for follow-up disability included a term examining interaction between principal component scores and exercise.

RESULTS

Exercisers had significantly different scores for PC2 (p = .02) and PC3 (p = .03), lower baseline (p = .005) and follow-up pain intensity (p < .001), follow-up disability (p < .001) and faster forward-bend times (p = .014). There was no significant interaction between exercise and PC2 (p = .92) or PC3 (p = .75).

CONCLUSIONS

This study showed no interaction between psychological factors and exercise on disability at follow-up. These findings suggest that the disability outcome of people with CLBP who undertake exercise as an intervention does not differ from those who do not undertake exercise, irrespective of their baseline psychological status.

A permutation procedure to detect heterogeneous treatments effects in randomized clinical trials while controlling the type I error rate

BACKGROUND/AIMS

Secondary analyses of randomized clinical trials often seek to identify subgroups with differential treatment effects. These discoveries can help guide individual treatment decisions based on patient characteristics and identify populations for which additional treatments are needed. Traditional analyses require researchers to pre-specify potential subgroups to reduce the risk of reporting spurious results. There is a need for methods that can detect such subgroups without a priori specification while allowing researchers to control the probability of falsely detecting heterogeneous subgroups when treatment effects are uniform across the study population.

METHODS

We propose a permutation procedure for tuning parameter selection that allows for type I error control when testing for heterogeneous treatment effects framed within the Virtual Twins procedure for subgroup identification. We verify that the type I error rate can be controlled at the nominal rate and investigate the power for detecting heterogeneous effects when present through extensive simulation studies. We apply our method to a secondary analysis of data from a randomized trial of very low nicotine content cigarettes.

RESULTS

In the absence of type I error control, the observed type I error rate for Virtual Twins was between 99% and 100%. In contrast, models tuned via the proposed permutation were able to control the type I error rate and detect heterogeneous effects when present. An application of our approach to a recently completed trial of very low nicotine content cigarettes identified several variables with potentially heterogeneous treatment effects.

CONCLUSIONS

The proposed permutation procedure allows researchers to engage in secondary analyses of clinical trials for treatment effect heterogeneity while maintaining the type I error rate without pre-specifying subgroups.

Heterogeneous treatment effects in social policy studies: An assessment of contemporary articles in the health and social sciences

PURPOSE

. Social policies are important determinants of population health but may have varying effects on subgroups of people. Evaluating heterogeneous treatment effects (HTEs) of social policies is critical to determine how social policies will affect health inequities. Methods for evaluating HTEs are not standardized. Little is known about how often and by what methods HTEs are assessed in social policy and health research.

METHODS

. A sample of 55 articles from 2019 on the health effects of social policies were evaluated for frequency of reporting HTEs; for what subgroupings HTEs were reported; frequency of a priori specification of intent to assess HTEs; and methods used for assessing HTEs.

RESULTS

. 24 (44%) studies described some form of HTE assessment, including by age, gender, education, race/ethnicity, and/or geography. Among studies assessing HTEs, 63% specified HTE assessment a priori, and most (71%) used descriptive methods such as stratification; 21% used statistical tests (e.g., interaction terms in a regression); and no studies used data-driven algorithms.

CONCLUSIONS

. Although understanding HTEs could enhance policy and practice-based efforts to reduce inequities, it is not routine research practice. Increased evaluation of HTEs across relevant subgroups is needed.

Do recommended interventions widen or narrow inequalities in musculoskeletal health? An equity-focussed systematic review of differential effectiveness

Background

It is unclear whether seven interventions recommended by Public Health England for preventing and managing common musculoskeletal conditions reduce or widen health inequalities in adults with musculoskeletal conditions.

Methods

We used citation searches of Web of Science (date of ‘parent publication’ for each intervention to April 2021) to identify original research articles reporting subgroup or moderator analyses of intervention effects by social stratifiers defined using the PROGRESS-Plus frameworks. Randomized controlled trials, controlled before-after studies, interrupted time series, systematic reviews presenting subgroup/stratified analyses or meta-regressions, individual participant data meta-analyses and modelling studies were eligible. Two reviewers independently assessed the credibility of effect moderation claims using Instrument to assess the Credibility of Effect Moderation Analyses. A narrative approach to synthesis was used (PROSPERO registration number: CRD42019140018).

Results

Of 1480 potentially relevant studies, seven eligible analyses of single trials and five meta-analyses were included. Among these, we found eight claims of potential differential effectiveness according to social characteristics, but none that were judged to have high credibility.

Conclusions

In the absence of highly credible evidence of differential effectiveness in different social groups, and given ongoing national implementation, equity concerns may be best served by investing in monitoring and action aimed at ensuring fair access to these interventions.

Predictors and moderators of outcome of psychotherapeutic interventions for mental disorders in adolescents and young adults: protocol for systematic reviews

BACKGROUND

Adolescence and young adulthood is a risk period for the emergence of mental disorders. There is strong evidence that psychotherapeutic interventions are effective for most mental disorders. However, very little is known about which of the different psychotherapeutic treatment modalities are effective for whom. This large systematic review aims to address this critical gap within the literature on non-specific predictors and moderators of the outcomes of psychotherapeutic interventions among adolescents and young adults with mental disorders.

METHODS

The protocol is being reported in accordance with the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P) Statement. PubMed and PsycINFO databases will be searched for randomized controlled and quasi-experimental/naturalistic clinical trials. Risk of bias of all included studies will be assessed by the Mixed Methods Appraisal Tool. The quality of predictor and moderator variables will be also assessed. A narrative synthesis will be conducted for all included studies.

DISCUSSION

This systematic review will strengthen the evidence base on effective mental health interventions for young people, being the first to explore predictors and moderators of outcome of psychotherapeutic interventions for a wide range of mental disorders in young people.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42020166756 .

Weight loss outcomes in premenopausal versus postmenopausal women during behavioral weight loss interventions: a systematic review and meta-analysis

IMPORTANCE

Weight loss may be difficult for young women with obesity to achieve due to competing priorities (caring for children and/or full-time work), limiting their ability to engage in weight loss interventions. Older or postmenopausal women may also face challenges to weight loss such as caring responsibilities and menopause. Menopausal status may reflect differences in weight loss.

OBJECTIVE

This study compared changes in weight, fat mass, and lean mass in premenopausal versus postmenopausal women in dietary weight loss trials.

EVIDENCE REVIEW

We reviewed publications from January 2000 to June 2020 evaluating a weight loss intervention with a dietary component, with or without exercise, and reporting weight loss of premenopausal and postmenopausal women. Where available, data on mean change from baseline for weight, fat mass, and lean mass of premenopausal and postmenopausal groups were entered into Review Manger for meta-analyses. Differences between menopausal groups were compared in subgroups of studies for intervention characteristics (diet-only vs diet and exercise; dietary modification vs meal replacement; < 24 wks vs ≥24 wks duration).

FINDINGS

Seven publications (10 interventions, n = 791) were included; three single-arm trials, two randomized controlled trials, and two comparative effectiveness trials. In meta-analyses, there were no statistically significant differences between premenopausal and postmenopausal women (shown as premenopausal minus postmenopausal) for change in weight (0.58 [95% confidence interval -0.12 to 1.28] kg, n = 7 interventions), fat mass (0.73 [-0.25 to 1.70] kg, n = 6 interventions), or lean mass (-0.5 6[-1.48 to 0.36] kg, n = 4 interventions). However, a statistically significant subgroup difference was observed for fat mass change between menopausal groups (premenopausal minus postmenopausal) when comparing diet-only (1.28 [0.23 to 2.33] kg, n = 4 interventions) versus diet and exercise interventions (-0.09 [-0.51 to 0.32]kg, n = 2 interventions). No differences were shown in any other subgroups.

CONCLUSIONS AND RELEVANCE

This review provides some evidence to suggest weight loss interventions may not need to be tailored to women's menopausal status. However, given the small number of studies, short intervention duration in most publications (≤ 6 mo) and unclear retention rates in premenopausal versus postmenopausal groups of some publications, menopausal group differences should be examined in existing and future trials where the appropriate data have been collected.

Effectiveness of nicotine gum in preventing lapses in the face of temptation to smoke among non-daily smokers: a secondary analysis

BACKGROUND AND AIMS

Non-daily smokers (NDS) comprise a large fraction of US smokers. Despite little or no dependence, as typically assessed, intermittent smokers (ITS) have difficulty quitting smoking. A randomized clinical trial comparing the effect of nicotine gum with placebo on quitting smoking in non-daily smokers did not find an effect on overall abstinence. We undertook an analysis to assess whether using nicotine gum versus placebo when tempted to smoke could reduce incidence of lapses in those situations.

DESIGN

Within a 6-week randomized, placebo-controlled clinical trial of nicotine gum, analyses contrasted the outcome of temptation episodes where gum was or was not used.

SETTING

Smoking cessation research clinic in Pittsburgh, PA, USA.

PARTICIPANTS

A total of 255 adult ITS (131 nicotine gum, 124 placebo) seeking help for smoking cessation.

INTERVENTION

Nicotine gum (2 mg) versus placebo for up to 8 weeks, with as-needed dosing instructions.

MEASUREMENTS

Outcome was lapsing in temptation episodes, as reported by participants via ecological momentary assessment (EMA). Propensity scores predicting gum use from situational factors (e.g. mood, social setting, smoking cues) served as a control variable.

FINDINGS

Participants reported 2713 temptation episodes, 46.0% (1248) of which resulted in smoking (lapsing). There was a significant gum use × active treatment interaction (P = 0.0009). Using nicotine gum decreased the odds of lapsing by 55% compared with using placebo [odds ratio (OR) = 0.45; 0.22-0.94]; when gum was not used, the assigned gum condition made no significant difference (OR = 1.53; 0.78-3.01; Bayes factor = 0.14). The nicotine effect was not reliably different when participants were trying to achieve abstinence versus when trying to maintain abstinence (OR = 0.44; 0.10, 2.03; P = 0.294; Bayes factor = 0.11), for men and women (OR = 1.68; 0.58, 4.87; P = 0.343; Bayes factor = 0.10), or for participants with some or no dependence (OR = 0.88; 0.30, 2.59; P = 0.811; Bayes factor = 0.06).

CONCLUSIONS

When used in response to temptation to smoke, 2 mg nicotine gum can help to prevent lapses among non-daily smokers.

Moderators of treatment effects in a child maltreatment prevention programme in South Africa

BACKGROUND

Previous research has found mixed results on whether the most disadvantaged families benefit as much as less disadvantaged families from parenting interventions designed to reduce child maltreatment, and little in known in low-income settings.

OBJECTIVE

In this study, we test the effects of child, caregiver, household, and community characteristics as treatment moderators of intervention outcomes - child maltreatment and parenting practices. We test characteristics previously examined elsewhere as well as factors relevant to the South African context.

PARTICIPANTS AND SETTING

This analysis includes adolescents (ages 10-18) and their caregivers (N = 552 pairs) who participated in a randomised trial of a parenting programme in the Eastern Cape Province of South Africa.

METHODS

Data from the caregiver and adolescent standardised questionnaires collected at baseline, post-test (1-month post-intervention), and follow-up (5-9 months) were analysed using longitudinal multilevel analyses. We tested seven hypothesised moderators for each of the primary outcomes through interactions of treatment effect with baseline moderators.

RESULTS

No moderator effects were statistically significant after correcting for multiple comparisons testing. Hence, in line with several recent studies examining moderation effects in parenting programmes, our study suggests that parenting interventions aiming to reduce child maltreatment and promote parenting skills in low- and middle-income countries may be similarly effective for families facing various levels of economic, social, and health risk factors.

CONCLUSIONS

It may be useful to explicitly power trials for testing moderator effects, study different types of moderators and use person-centred analyses to further understand variations in treatment effects.

The smoking cessation in pregnancy incentives trial (CPIT): study protocol for a phase III randomised controlled trial

BACKGROUND

Eighty per cent of UK women have at least one baby, making pregnancy an opportunity to help women stop smoking before their health is irreparably compromised. Smoking cessation during pregnancy helps protect infants from miscarriage, still birth, low birth weight, asthma, attention deficit disorder and adult cardiovascular disease. UK national guidelines highlight lack of evidence for effectiveness of financial incentives to help pregnant smokers quit. This includes a research recommendation: within a UK context, are incentives an acceptable, effective and cost-effective way to help pregnant women who smoke to quit?

METHODS

The Cessation in Pregnancy Incentives Trial (CPIT) III is a pragmatic, 42-month, multi-centre, parallel-group, individually randomised controlled superiority trial of the effect on smoking status of adding to usual Stop Smoking Services (SSS) support, the offer of up to £400 of financial voucher incentives, compared with usual support alone, to quit smoking during pregnancy. Participants (n = 940) are pregnant smokers (age > 16 years, < 24 weeks pregnant, English speaking), who consent via telephone to take part and are willing to be followed-up in late pregnancy and 6 months after birth. The primary outcome is cotinine/anabasine-validated abstinence from smoking in late pregnancy. Secondary outcomes include engagement with SSS, quit rates at 4 weeks from agreed quit date and 6 months after birth, and birth weight. Outcomes will be analysed by intention to treat, and regression models will be used to compare treatment effects on outcomes. A meta-analysis will include data from the feasibility study in Glasgow. An economic evaluation will assess cost-effectiveness from a UK NHS perspective. Process evaluation using a case-study approach will identify opportunities to improve recruitment and learning for future implementation. Research questions include: what is the therapeutic efficacy of incentives; are incentives cost-effective; and what are the potential facilitators and barriers to implementing incentives in different parts of the UK?

DISCUSSION

This phase III trial in Scotland, England and Northern Ireland follows a successful phase II trial in Glasgow, UK. The participating sites have diverse SSS that represent most cessation services in the UK and serve demographically varied populations. If found to be acceptable and cost-effective, this trial could demonstrate that financial incentives are effective and transferable to most UK SSS for pregnant women.

TRIAL REGISTRATION

Current Controlled Trials, ISRCTN15236311. Registered on 9 October 2017.

Psychological interventions for common mental disorders in women experiencing intimate partner violence in low-income and middle-income countries: a systematic review and meta-analysis

BACKGROUND

Evidence on the effectiveness of psychological interventions for women with common mental disorders (CMDs) who also experience intimate partner violence is scarce. We aimed to test our hypothesis that exposure to intimate partner violence would reduce intervention effectiveness for CMDs in low-income and middle-income countries (LMICs).

METHODS

For this systematic review and meta-analysis, we searched MEDLINE, Embase, PsycINFO, Web of Knowledge, Scopus, CINAHL, LILACS, ScieELO, Cochrane, PubMed databases, trials registries, 3ie, Google Scholar, and forward and backward citations for studies published between database inception and Aug 16, 2019. All randomised controlled trials (RCTs) of psychological interventions for CMDs in LMICs which measured intimate partner violence were included, without language or date restrictions. We approached study authors to obtain unpublished aggregate subgroup data for women who did and did not report intimate partner violence. We did separate random-effects meta-analyses for anxiety, depression, post-traumatic stress disorder (PTSD), and psychological distress outcomes. Evidence from randomised controlled trials was synthesised as differences between standardised mean differences (SMDs) for change in symptoms, comparing women who did and who did not report intimate partner violence via random-effects meta-analyses. The quality of the evidence was assessed with the Cochrane risk of bias tool. This study is registered on PROSPERO, number CRD42017078611.

FINDINGS

Of 8122 records identified, 21 were eligible and data were available for 15 RCTs, all of which had a low to moderate risk of overall bias. Anxiety (five interventions, 728 participants) showed a greater response to intervention among women reporting intimate partner violence than among those who did not (difference in standardised mean differences [dSMD] 0·31, 95% CI 0·04 to 0·57, I²=49·4%). No differences in response to intervention were seen in women reporting intimate partner violence for PTSD (eight interventions, n=1436; dSMD 0·14, 95% CI -0·06 to 0·33, I²=42·6%), depression (12 interventions, n=2940; 0·10, -0·04 to 0·25, I²=49·3%), and psychological distress (four interventions, n=1591; 0·07, -0·05 to 0·18, I²=0·0%, p=0·681).

INTERPRETATION

Psychological interventions treat anxiety effectively in women with current or recent intimate partner violence exposure in LMICs when delivered by appropriately trained and supervised health-care staff, even when not tailored for this population or targeting intimate partner violence directly. Future research should investigate whether adapting evidence-based psychological interventions for CMDs to address intimate partner violence enhances their acceptability, feasibility, and effectiveness in LMICs.

FUNDING

UK National Institute for Health Research ASSET and King's IoPPN Clinician Investigator Scholarship.

Moderators of the effectiveness of an intervention to increase colorectal cancer screening through mailed fecal immunochemical test kits: results from a pragmatic randomized trial

Background

Colorectal cancer (CRC) screening rates remain suboptimal, particularly in low-income and underserved populations. Mailed fecal immunochemical testing (FIT) may overcome common barriers to screening; however, the effect of mailed FIT kits may differ across important subpopulations. The goal of the current study was to examine sociodemographic and health-related factors that moderate the effect of an intervention of automated direct mail of FIT kits at health clinics serving low-income populations.

Methods

This study is a secondary analysis of the Strategies and Opportunities to Stop Colon Cancer in Priority Populations (STOP CRC) study, a cluster-randomized pragmatic trial to increase uptake of CRC screening in patients seen at federally qualified health centers. The intervention involved tools embedded in the electronic medical records to enable participating clinics to mail FIT kits and related materials to eligible participants. We examined the rate of FIT completion by potential moderating characteristics using electronic health record data supplemented by the American Community Survey and the Centers for Medicare & Medicaid Services Geographic Variation datasets, linked via geocoding to patients’ addresses. All patients aged 50–75 seen in participating health clinics who were eligible for CRC screening were included.

Results

Although not always statistically significant, we saw a consistent pattern of increased FIT return rates among intervention participants compared to control participants across all subgroups studied, with incidence rate ratios (IRRs) generally ranging from 1.25 to 1.50. FIT completion in the intervention group ranged from 15 and 20% across subpopulations, typically three to six percentage points higher than the control group participants. The only moderator with a statistically significant interaction was race: persons of Asian descent showed a twofold response to the intervention (adjusted incidence rate ratio [aIRR] = 2.06, 95% confidence interval 1.41 to 3.00).

Conclusions

Response to a mailed FIT intervention was generally consistent across a wide range of individual and neighborhood-level patient characteristics, including typically underserved patients and those in low-resource communities.

Trial registration

ClinicalTrials.gov, NCT01742065. Registered on 5 December 2012.

A systematic survey identified 36 criteria for assessing effect modification claims in randomized trials or meta-analyses

OBJECTIVE

The objective of the study was to systematically survey the methodological literature and collect suggested criteria for assessing the credibility of effect modification and associated rationales.

STUDY DESIGN AND SETTING

We searched MEDLINE, Embase, and WorldCat up to March 2018 for publications providing guidance for assessing the credibility of effect modification identified in randomized trials or meta-analyses. Teams of two investigators independently identified eligible publications and extracted credibility criteria and authors' rationale, reaching consensus through discussion. We created a taxonomy of criteria that we iteratively refined during data abstraction.

RESULTS

We identified 150 eligible publications that provided 36 criteria and associated rationales. Frequent criteria included significant test for interaction (n = 54), a priori hypothesis (n = 49), providing a causal explanation (n = 47), accounting for multiplicity (n = 45), testing a small number of effect modifiers (n = 38), and prespecification of analytic details (n = 39). For some criteria, we found more than one rationale; some criteria were connected through a common rationale. For some criteria, experts disagreed regarding their suitability (e.g., added value of stratified randomization; trustworthiness of biologic rationales).

CONCLUSION

Methodologists have expended substantial intellectual energy providing criteria for critical appraisal of apparent effect modification. Our survey highlights popular criteria, expert agreement and disagreement, and where more work is needed, including testing criteria in practice.

Minimizing Drug Adverse Events by Informing About the Nocebo Effect-An Experimental Study

Relevance: Informing patients about potential adverse events as part of the informed consent may facilitate the development of nocebo-driven drug adverse events (nocebo side effects). Objective: To investigate whether informing about the nocebo effect using a short information sheet can reduce nocebo side effects. Methods: A total of N = 44 participants with weekly headaches for at least 6 months were recruited using the cover story of a clinical trial for a headache medicine. In reality, all participants took a placebo pill and were randomized to the nocebo information group or the standard leaflet group. Participants were instructed to read the bogus medication leaflet entailing side effects information shortly before pill intake. The nocebo group additionally received an explanation about the nocebo effect as part of the leaflet. Questionnaires were completed at baseline, 2 min, and 4 days after the pill intake. We conducted general linear models with bootstrap sampling. Baseline symptoms were included as a covariate. Results: Most participants (70.5%) reported nocebo side effects at 2 min. Participants who received the nocebo information (n = 24) reported less nocebo symptoms than the control group (n = 20) (estimated difference: 3.3, BCa 95% CI [1.14; 5.15], p = 0.01, Cohen's d = 0.59). Baseline symptoms, perceived sensitivity to medicine, and side effect expectations each moderated the group effect (estimated difference in slope: 0.47, BCa 95% CI [0.19; 0.73], p = 0.001, d = 0.75; 1.07 [0.27; 1.61], p = 0.006, d = 0.73; 1.57 [0.38; 2.76], p = 0.02, d = 0.58). No group differences were found at 4-day follow-up. After revealing the actual aim of the study, 86% of the participants evaluated the nocebo information to be helpful in general. Conclusions: Results provide the first evidence that informing about the nocebo effect can reduce nocebo side effects.

Baseline Psychological Inflexibility Moderates the Outcome Pain Interference in a Randomized Controlled Trial on Internet-based Acceptance and Commitment Therapy for Chronic Pain

This study re-investigated data of a randomized controlled trial on Internet-based Acceptance and Commitment Therapy for chronic pain (ACTonPain). Baseline psychological inflexibility was examined as a moderator of the outcome pain interference. In the ACTonPain trial, participants with chronic pain were randomized to one of three conditions: guided Internet-based ACT (n = 100), unguided Internet-based ACT (n = 101), and waitlist (n = 101). Moderation analyses were performed with the SPSS macro PROCESS. Pain interference according to the Multidimensional Pain Inventory (MPI) was the primary outcome in this trial, and the potential moderator psychological inflexibility was measured with the Acceptance and Action Questionnaire (AAQ-II). Psychological inflexibility at baseline moderated the outcome between guided Internet-based ACT and waitlist 9-weeks as well as 6-months after randomization. (both p < 0.05). Between unguided Internet-based ACT and waitlist, psychological inflexibility moderated the outcome 6-months after randomization (p < 0.05). Internet-based ACT was superior to waitlist for participants with less psychological inflexibility at baseline, but Internet-based ACT became increasingly comparable to waitlist at higher AAQ-II baseline values. Future research should investigate whether the results can be replicated in more individualized and tailored face-to-face settings.

Baseline Psychological Inflexibility Moderates the Outcome Pain Interference in a Randomized Controlled Trial on Internet-based Acceptance and Commitment Therapy for Chronic Pain

This study re-investigated data of a randomized controlled trial on Internet-based Acceptance and Commitment Therapy for chronic pain (ACTonPain). Baseline psychological inflexibility was examined as a moderator of the outcome pain interference. In the ACTonPain trial, participants with chronic pain were randomized to one of three conditions: guided Internet-based ACT (n = 100), unguided Internet-based ACT (n = 101), and waitlist (n = 101). Moderation analyses were performed with the SPSS macro PROCESS. Pain interference according to the Multidimensional Pain Inventory (MPI) was the primary outcome in this trial, and the potential moderator psychological inflexibility was measured with the Acceptance and Action Questionnaire (AAQ-II). Psychological inflexibility at baseline moderated the outcome between guided Internet-based ACT and waitlist 9-weeks as well as 6-months after randomization. (both p < 0.05). Between unguided Internet-based ACT and waitlist, psychological inflexibility moderated the outcome 6-months after randomization (p < 0.05). Internet-based ACT was superior to waitlist for participants with less psychological inflexibility at baseline, but Internet-based ACT became increasingly comparable to waitlist at higher AAQ-II baseline values. Future research should investigate whether the results can be replicated in more individualized and tailored face-to-face settings.