Patient Health Questionnaire-9 scores do not accurately estimate depression prevalence: individual participant data meta-analysis

OBJECTIVES

Depression symptom questionnaires are not for diagnostic classification. Patient Health Questionnaire-9 (PHQ-9) scores ≥10 are nonetheless often used to estimate depression prevalence. We compared PHQ-9 ≥10 prevalence to Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders (SCID) major depression prevalence and assessed whether an alternative PHQ-9 cutoff could more accurately estimate prevalence.

STUDY DESIGN AND SETTING

Individual participant data meta-analysis of datasets comparing PHQ-9 scores to SCID major depression status.

RESULTS

A total of 9,242 participants (1,389 SCID major depression cases) from 44 primary studies were included. Pooled PHQ-9 ≥10 prevalence was 24.6% (95% confidence interval [CI]: 20.8%, 28.9%); pooled SCID major depression prevalence was 12.1% (95% CI: 9.6%, 15.2%); and pooled difference was 11.9% (95% CI: 9.3%, 14.6%). The mean study-level PHQ-9 ≥10 to SCID-based prevalence ratio was 2.5 times. PHQ-9 ≥14 and the PHQ-9 diagnostic algorithm provided prevalence closest to SCID major depression prevalence, but study-level prevalence differed from SCID-based prevalence by an average absolute difference of 4.8% for PHQ-9 ≥14 (95% prediction interval: -13.6%, 14.5%) and 5.6% for the PHQ-9 diagnostic algorithm (95% prediction interval: -16.4%, 15.0%).

CONCLUSION

PHQ-9 ≥10 substantially overestimates depression prevalence. There is too much heterogeneity to correct statistically in individual studies.

State of the Art Review: Brachial-Ankle PWV

The brachial-ankle pulse wave velocity (brachial-ankle PWV), which is measured simply by wrapping pressure cuffs around the four extremities, is a simple marker to assess the stiffness of the medium- to large- sized arteries. The accuracy and reproducibility of its measurement have been confirmed to be acceptable. Risk factors for cardiovascular disease, especially advanced age and high blood pressure, are reported to be associated with an increase of the arterial stiffness. Furthermore, arterial stiffness might be involved in a vicious cycle with the development/progression of hypertension, diabetes mellitus and chronic kidney disease. Increase in the arterial stiffness is thought to contribute to the development of cardiovascular disease via pathophysiological abnormalities induced in the heart, brain, kidney, and also the arteries themselves. A recent independent participant data meta-analysis conducted in Japan demonstrated that the brachial-ankle PWV is a useful marker to predict future cardiovascular events in Japanese subjects without a previous history of cardiovascular disease, independent of the conventional model for the risk assessment. The cutoff point may be 16.0 m/s in individuals with a low risk of cardiovascular disease (CVD), and 18.0 m/s in individuals with a high risk of CVD and subjects with hypertension. In addition, the method of measurement of the brachial-ankle PWV can also be used to calculate the inter-arm systolic blood pressure difference and ankle-brachial pressure index, which are also useful markers for cardiovascular risk assessment.

Efficacy and Moderators of Internet-Based Interventions in Adults with Subthreshold Depression: An Individual Participant Data Meta-Analysis of Randomized Controlled Trials

INTRODUCTION

Evidence on effects of Internet-based interventions to treat subthreshold depression (sD) and prevent the onset of major depression (MDD) is inconsistent.

OBJECTIVE

We conducted an individual participant data meta-analysis to determine differences between intervention and control groups (IG, CG) in depressive symptom severity (DSS), treatment response, close to symptom-free status, symptom deterioration and MDD onset as well as moderators of intervention outcomes.

METHODS

Randomized controlled trials were identified through systematic searches via PubMed, PsycINFO, Embase and Cochrane Library. Multilevel regression analyses were used to examine efficacy and moderators.

RESULTS

Seven trials (2,186 participants) were included. The IG was superior in DSS at all measurement points (posttreatment: 6-12 weeks; Hedges' g = 0.39 [95% CI: 0.25-0.53]; follow-up 1: 3-6 months; g = 0.30 [95% CI: 0.15-0.45]; follow-up 2: 12 months, g = 0.27 [95% CI: 0.07-0.47], compared with the CG. Significantly more participants in the IG than in the CG reached response and close to symptom-free status at all measurement points. A significant difference in symptom deterioration between the groups was found at the posttreatment assessment and follow-up 2. Incidence rates for MDD onset within 12 months were lower in the IG (19%) than in the CG (26%). Higher initial DSS and older age were identified as moderators of intervention effect on DSS.

CONCLUSIONS

Our findings provide evidence for Internet-based interventions to be a suitable low-threshold intervention to treat individuals with sD and to reduce the incidence of MDD. This might be particularly true for older people with a substantial symptom burden.

Determining a global mid-upper arm circumference cut-off to assess underweight in adults (men and non-pregnant women)

OBJECTIVE

To determine if a global mid-upper arm circumference (MUAC) cut-off can be established to classify underweight in adults (men and non-pregnant women).

DESIGN

We conducted an individual participant data meta-analysis (IPDMA) to explore the sensitivity (SENS) and specificity (SPEC) of various MUAC cut-offs for identifying underweight among adults (defined as BMI < 18·5 kg/m2). Measures of diagnostic accuracy were determined every 0·5 cm across MUAC values from 19·0 to 26·5 cm. A bivariate random effects model was used to jointly estimate SENS and SPEC while accounting for heterogeneity between studies. Various subgroup analyses were performed.

SETTING

Twenty datasets from Africa, South Asia, Southeast Asia, North America and South America were included.

PARTICIPANTS

All eligible participants from the original datasets were included.

RESULTS

The total sample size was 13 835. Mean age was 32·6 years and 65 % of participants were female. Mean MUAC was 25·7 cm, and 28 % of all participants had low BMI (<18·5 kg/m2). The area under the receiver operating characteristic curve for the pooled dataset was 0·91 (range across studies 0·61-0·98). Results showed that MUAC cut-offs in the range of ≤23·5 to ≤25·0 cm could serve as an appropriate screening indicator for underweight.

CONCLUSIONS

MUAC is highly discriminatory in its ability to distinguish adults with BMI above and below 18·5 kg/m2. This IPDMA is the first step towards determining a global MUAC cut-off for adults. Validation studies are needed to determine whether the proposed MUAC cut-off of 24 cm is associated with poor functional outcomes.

Effects of dietary and physical activity interventions on the risk of type 2 diabetes in South Asians: meta-analysis of individual participant data from randomised controlled trials

AIMS/HYPOTHESIS

Individuals of South Asian origin have a high risk of type 2 diabetes and of dying from a diabetes-attributable cause. Lifestyle modification intervention trials to prevent type 2 diabetes in high-risk South Asian adults have suggested more modest effects than in European-origin populations. The strength of the evidence of individual studies is limited, however. We performed an individual participant data meta-analysis of available RCTs to assess the effectiveness of lifestyle modification in South Asian populations worldwide.

METHODS

We searched PubMed, EMBASE, Cochrane Library and Web of Science (to 24 September 2018) for RCTs on lifestyle modification interventions incorporating diet and/or physical activity in South Asian adults. Reviewers identified eligible studies and assessed the quality of the evidence. We obtained individual participant data on 1816 participants from all six eligible trials (four from Europe and two from India). We generated HR estimates for incident diabetes (primary outcome) and mean differences for fasting glucose, 2 h glucose, weight and waist circumference (secondary outcomes) using mixed-effect meta-analysis overall and by pre-specified subgroups. We used the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system to rate the quality of evidence of the estimates. The study is registered with the International Prospective Register of Systematic Reviews ([PROSPERO] CRD42017078003).

RESULTS

Incident diabetes was observed in 12.6% of participants in the intervention groups and in 20.0% of participants in the control groups. The pooled HR for diabetes incidence was 0.65 (95% CI 0.51, 0.81; I² = 0%) in intervention compared with control groups. The absolute risk reduction was 7.4% (95% CI 4.0, 10.2), with no interactions for the pre-specified subgroups (sex, BMI, age, study duration and region where studies were performed). The quality of evidence was rated as moderate. Mean difference for lifestyle modification vs control groups for 2 h glucose was -0.34 mmol/l (95% CI -0.62, -0.07; I² = 50%); for weight -0.75 kg (95% CI -1.34, -0.17; I² = 71%) and for waist -1.16 cm (95% CI -2.16, -0.16; I² = 75%). No effect was found for fasting glucose. Findings were similar across subgroups, except for weight for European vs Indian studies (-1.10 kg vs -0.08 kg, p = 0.02 for interaction).

CONCLUSIONS/INTERPRETATION

Despite modest changes for adiposity, lifestyle modification interventions in high-risk South Asian populations resulted in a clinically important 35% relative reduction in diabetes incidence, consistent across subgroups. If implemented on a large scale, lifestyle modification interventions in high-risk South Asian populations in Europe would reduce the incidence of diabetes in these populations.

Obtaining and managing data sets for individual participant data meta-analysis: scoping review and practical guide

BACKGROUND

Shifts in data sharing policy have increased researchers' access to individual participant data (IPD) from clinical studies. Simultaneously the number of IPD meta-analyses (IPDMAs) is increasing. However, rates of data retrieval have not improved. Our goal was to describe the challenges of retrieving IPD for an IPDMA and provide practical guidance on obtaining and managing datasets based on a review of the literature and practical examples and observations.

METHODS

We systematically searched MEDLINE, Embase, and the Cochrane Library, until January 2019, to identify publications focused on strategies to obtain IPD. In addition, we searched pharmaceutical websites and contacted industry organizations for supplemental information pertaining to recent advances in industry policy and practice. Finally, we documented setbacks and solutions encountered while completing a comprehensive IPDMA and drew on previous experiences related to seeking and using IPD.

RESULTS

Our scoping review identified 16 articles directly relevant for the conduct of IPDMAs. We present short descriptions of these articles alongside overviews of IPD sharing policies and procedures of pharmaceutical companies which display certification of Principles for Responsible Clinical Trial Data Sharing via Pharmaceutical Research and Manufacturers of America or European Federation of Pharmaceutical Industries and Associations websites. Advances in data sharing policy and practice affected the way in which data is requested, obtained, stored and analyzed. For our IPDMA it took 6.5 years to collect and analyze relevant IPD and navigate additional administrative barriers. Delays in obtaining data were largely due to challenges in communication with study sponsors, frequent changes in data sharing policies of study sponsors, and the requirement for a diverse skillset related to research, administrative, statistical and legal issues.

CONCLUSIONS

Knowledge of current data sharing practices and platforms as well as anticipation of necessary tasks and potential obstacles may reduce time and resources required for obtaining and managing data for an IPDMA. Sufficient project funding and timeline flexibility are pre-requisites for successful collection and analysis of IPD. IPDMA researchers must acknowledge the additional and unexpected responsibility they are placing on corresponding study authors or data sharing administrators and should offer assistance in readying data for sharing.

Probability of major depression diagnostic classification based on the SCID, CIDI and MINI diagnostic interviews controlling for Hospital Anxiety and Depression Scale - Depression subscale scores: An individual participant data meta-analysis of 73 primary studies

OBJECTIVE

Two previous individual participant data meta-analyses (IPDMAs) found that different diagnostic interviews classify different proportions of people as having major depression overall or by symptom levels. We compared the odds of major depression classification across diagnostic interviews among studies that administered the Depression subscale of the Hospital Anxiety and Depression Scale (HADS-D).

METHODS

Data accrued for an IPDMA on HADS-D diagnostic accuracy were analysed. We fit binomial generalized linear mixed models to compare odds of major depression classification for the Structured Clinical Interview for DSM (SCID), Composite International Diagnostic Interview (CIDI), and Mini International Neuropsychiatric Interview (MINI), controlling for HADS-D scores and participant characteristics with and without an interaction term between interview and HADS-D scores.

RESULTS

There were 15,856 participants (1942 [12%] with major depression) from 73 studies, including 15,335 (97%) non-psychiatric medical patients, 164 (1%) partners of medical patients, and 357 (2%) healthy adults. The MINI (27 studies, 7345 participants, 1066 major depression cases) classified participants as having major depression more often than the CIDI (10 studies, 3023 participants, 269 cases) (adjusted odds ratio [aOR] = 1.70 (0.84, 3.43)) and the semi-structured SCID (36 studies, 5488 participants, 607 cases) (aOR = 1.52 (1.01, 2.30)). The odds ratio for major depression classification with the CIDI was less likely to increase as HADS-D scores increased than for the SCID (interaction aOR = 0.92 (0.88, 0.96)).

CONCLUSION

Compared to the SCID, the MINI may diagnose more participants as having major depression, and the CIDI may be less responsive to symptom severity.

The efficacy of adding short-term psychodynamic psychotherapy to antidepressants in the treatment of depression: A systematic review and meta-analysis of individual participant data

PURPOSE

We examined the efficacy of adding short-term psychodynamic psychotherapy (STPP) to antidepressants in the treatment of depression by means of a systematic review and meta-analysis of individual participant data, which is currently considered the most reliable method for evidence synthesis.

RESULTS

A thorough systematic literature search resulted in 7 studies comparing combined treatment of antidepressants and STPP versus antidepressant mono-therapy (n = 3) or versus antidepressants and brief supportive psychotherapy (n = 4). Individual participant data were obtained for all these studies and totaled 482 participants. Across the total sample of studies, combined treatment of antidepressants and STPP was found significantly more efficacious in terms of depressive symptom levels at both post-treatment (Cohen's d = 0.26, SE = 0.10, p = .01) and follow-up (d = 0.50, SE = 0.10, p < .001). This effect was most apparent at follow-up and in studies examining STPP's specific treatment efficacy. Effects were still apparent in analyses that controlled for risk of bias and STPP quality in the primary studies.

CONCLUSIONS

These findings support the evidence-base of adding STPP to antidepressants in the treatment of depression. However, further studies are needed, particularly assessing outcome measures other than depression and cost-effectiveness, as well as examining the relative merits of STPP versus other psychotherapies as added to antidepressants.

The effects of dietary and lifestyle interventions among pregnant women with overweight or obesity on early childhood outcomes: an individual participant data meta-analysis from randomised trials

BACKGROUND

The impact of maternal obesity extends beyond birth, being independently associated with an increased risk of child obesity. Current evidence demonstrates that women provided with a dietary intervention during pregnancy improve their dietary quality and have a modest reduction in gestational weight gain. However, the effect of this on longer-term childhood obesity-related outcomes is unknown.

METHODS

We conducted an individual participant data meta-analysis from RCTs in which women with a singleton, live gestation between 10⁺⁰ and 20⁺⁰ weeks and body mass index (BMI) ≥ 25 kg/m² in early pregnancy were randomised to a diet and/or lifestyle intervention or continued standard antenatal care and in which longer-term maternal and child follow-up at 3-5 years of age had been undertaken. The primary childhood outcome was BMI z-score above the 90th percentile. Secondary childhood outcomes included skinfold thickness measurements and body circumferences, fat-free mass, dietary and physical activity patterns, blood pressure, and neurodevelopment.

RESULTS

Seven primary trials where follow-up of participants occurred were identified by a systematic literature search within the International Weight Management in Pregnancy (i-WIP) Collaborative Group collaboration, with six providing individual participant data. No additional studies were identified after a systematic literature search. A total of 2529 children and 2383 women contributed data. Approximately 30% of all child participants had a BMI z-score above the 90th percentile, with no significant difference between the intervention and control groups (aRR 0.97; 95% CI 0.87, 1.08; p=0.610). There were no statistically significant differences identified for any of the secondary outcome measures.

CONCLUSIONS

In overweight and obese pregnant women, we found no evidence that maternal dietary and/or lifestyle intervention during pregnancy modifies the risk of early childhood obesity. Future research may need to target the pre-conception period in women and early childhood interventions.

TRIAL REGISTRATION

PROSPERO, CRD42016047165.

Oxygen saturation target ranges and alarm settings in the NICU: What have we learnt from the neonatal oxygenation prospective meta-analysis (NeOProM)?

The Neonatal Oxygenation Prospective Meta-analysis combined the individual participant data of 4965 extremely preterm infants. They had been randomly assigned in 5 trials to arterial oxygen saturations of 85%-89% or 91%-95% using modified oximeters to mask the treatment allocation. The primary outcome of death or disability did not differ significantly between the groups. Assignment to the higher target range reduced the risks of death and severe necrotizing enterocolitis but increased the risk of treated retinopathy. Trade-offs between the benefits and risks of higher or lower saturation targets should be informed by the local patient risks and institutional rates for outcomes that may be affected by a policy change. Features of the oximeter masking algorithm introduced unanticipated artifacts into the saturation display that are not seen in routine care. NeOProM provides little guidance on where to set the oximeter alarms and how to respond to them.

Towards a consensus definition of allostatic load: a multi-cohort, multi-system, multi-biomarker individual participant data (IPD) meta-analysis

BACKGROUND

Allostatic load (AL) is a multi-system composite index for quantifying physiological dysregulation caused by life course stressors. For over 30 years, an extensive body of research has drawn on the AL framework but has been hampered by the lack of a consistent definition.

METHODS

This study analyses data for 67,126 individuals aged 40-111 years participating in 13 different cohort studies and 40 biomarkers across 12 physiological systems: hypothalamic-pituitary-adrenal (HPA) axis, sympathetic-adrenal-medullary (SAM) axis, parasympathetic nervous system functioning, oxidative stress, immunological/inflammatory, cardiovascular, respiratory, lipidemia, anthropometric, glucose metabolism, kidney, and liver. We use individual-participant-data meta-analysis and exploit natural heterogeneity in the number and type of biomarkers that have been used across studies, but a common set of health outcomes (grip strength, walking speed, and self-rated health), to determine the optimal configuration of parameters to define the concept.

RESULTS

There was at least one biomarker within 9/12 physiological systems that was reliably and consistently associated in the hypothesised direction with the three health outcomes in the meta-analysis of these cohorts: dehydroepiandrosterone sulfate (DHEAS), low frequency-heart rate variability (LF-HRV), C-reactive protein (CRP), resting heart rate (RHR), peak expiratory flow (PEF), high density lipoprotein cholesterol (HDL-C), waist-to-height ratio (WtHR), HbA1c, and cystatin C. An index based on five biomarkers (CRP, RHR, HDL-C, WtHR and HbA1c) available in every study was found to predict an independent outcome - mortality - as well or better than more elaborate sets of biomarkers.

DISCUSSION

This study has identified a brief 5-item measure of AL that arguably represents a universal and efficient set of biomarkers for capturing physiological 'wear and tear' and a further biomarker (PEF) that could usefully be included in future data collection.

A better understanding of the association between maternal perception of foetal movements and late stillbirth-findings from an individual participant data meta-analysis

BACKGROUND

Late stillbirth continues to affect 3-4/1000 pregnancies in high-resource settings, with even higher rates in low-resource settings. Reduced foetal movements are frequently reported by women prior to foetal death, but there remains a poor understanding of the reasons and how to deal with this symptom clinically, particularly during the preterm phase of gestation. We aimed to determine which women are at the greatest odds of stillbirth in relation to the maternal report of foetal movements in late pregnancy (≥ 28 weeks' gestation).

METHODS

This is an individual participant data meta-analysis of all identified case-control studies of late stillbirth. Studies included in the IPD were two from New Zealand, one from Australia, one from the UK and an internet-based study based out of the USA. There were a total of 851 late stillbirths, and 2257 controls with ongoing pregnancies.

RESULTS

Increasing strength of foetal movements was the most commonly reported (> 60%) pattern by women in late pregnancy, which were associated with a decreased odds of late stillbirth (adjusted odds ratio (aOR) = 0.20, 95% CI 0.15 to 0.27). Compared to no change in strength or frequency women reporting decreased frequency of movements in the last 2 weeks had increased odds of late stillbirth (aOR = 2.33, 95% CI 1.73 to 3.14). Interaction analysis showed increased strength of movements had a greater protective effect and decreased frequency of movements greater odds of late stillbirth at preterm gestations (28-36 weeks' gestation). Foetal hiccups (aOR = 0.45, 95% CI 0.36 to 0.58) and regular episodes of vigorous movement (aOR = 0.67, 95% CI 0.52 to 0.87) were associated with decreased odds of late stillbirth. A single episode of unusually vigorous movement was associated with increased odds (aOR = 2.86, 95% CI 2.01 to 4.07), which was higher in women at term.

CONCLUSIONS

Reduced foetal movements are associated with late stillbirth, with the association strongest at preterm gestations. Foetal hiccups and multiple episodes of vigorous movements are reassuring at all gestations after 28 weeks' gestation, whereas a single episode of vigorous movement is associated with stillbirth at term.

Probability of Major Depression Classification Based on the SCID, CIDI, and MINI Diagnostic Interviews: A Synthesis of Three Individual Participant Data Meta-Analyses

INTRODUCTION

Three previous individual participant data meta-analyses (IPDMAs) reported that, compared to the Structured Clinical Interview for the DSM (SCID), alternative reference standards, primarily the Composite International Diagnostic Interview (CIDI) and the Mini International Neuropsychiatric Interview (MINI), tended to misclassify major depression status, when controlling for depression symptom severity. However, there was an important lack of precision in the results.

OBJECTIVE

To compare the odds of the major depression classification based on the SCID, CIDI, and MINI.

METHODS

We included and standardized data from 3 IPDMA databases. For each IPDMA, separately, we fitted binomial generalized linear mixed models to compare the adjusted odds ratios (aORs) of major depression classification, controlling for symptom severity and characteristics of participants, and the interaction between interview and symptom severity. Next, we synthesized results using a DerSimonian-Laird random-effects meta-analysis.

RESULTS

In total, 69,405 participants (7,574 [11%] with major depression) from 212 studies were included. Controlling for symptom severity and participant characteristics, the MINI (74 studies; 25,749 participants) classified major depression more often than the SCID (108 studies; 21,953 participants; aOR 1.46; 95% confidence interval [CI] 1.11-1.92]). Classification odds for the CIDI (30 studies; 21,703 participants) and the SCID did not differ overall (aOR 1.19; 95% CI 0.79-1.75); however, as screening scores increased, the aOR increased less for the CIDI than the SCID (interaction aOR 0.64; 95% CI 0.52-0.80).

CONCLUSIONS

Compared to the SCID, the MINI classified major depression more often. The odds of the depression classification with the CIDI increased less as symptom levels increased. Interpretation of research that uses diagnostic interviews to classify depression should consider the interview characteristics.

The effects of dietary and lifestyle interventions among pregnant women who are overweight or obese on longer-term maternal and early childhood outcomes: protocol for an individual participant data (IPD) meta-analysis

BACKGROUND

The aim of this individual participant data meta-analysis (IPDMA) is to evaluate the effects of dietary and lifestyle interventions among pregnant women who are overweight or obese on later maternal and early childhood outcomes at ages 3-5 years.

METHODS/DESIGN

We will build on the established International Weight Management in Pregnancy (i-WIP) IPD Collaborative Network, having identified researchers who have conducted randomised dietary and lifestyle interventions among pregnant women who are overweight or obese, and where ongoing childhood follow-up of participants has been or is being undertaken. The primary maternal outcome is a diagnosis of maternal metabolic syndrome. The primary childhood outcome is BMI above 90%. We have identified 7 relevant trials, involving 5425 women who were overweight or obese during pregnancy, with approximately 3544 women and children with follow-up assessments available for inclusion in the meta-analysis.

DISCUSSION

The proposed IPDMA provides an opportunity to evaluate the effect of dietary and lifestyle interventions among pregnant women who are overweight or obese on later maternal and early childhood health outcomes, including risk of obesity. This knowledge is essential to effectively translate research findings into clinical practice and public health policy.

SYSTEMATIC REVIEW REGISTRATION

This IPD has been prospectively registered (PROSPERO), ID number CRD42016047165 .

Acceptance and commitment therapy for chronic pain: protocol of a systematic review and individual participant data meta-analysis

BACKGROUND

Acceptance and commitment therapy (ACT) can be effective in treating chronic pain. Despite evidence supporting the effectiveness of ACT, uncertainties remain regarding which subgroups in the chronic pain population are likely to benefit most and least. This protocol describes the application for two meta-analytic approaches, one at the level of individual participant data and the other at the level of aggregated data, from randomized controlled trials of ACT for chronic pain (ACT-CP-MA).

METHODS

We will systematically conduct literature searches in CENTRAL, MEDLINE, EMBASE, PsycINFO, and trial registers. Two reviewers will independently select studies for inclusion and data extraction. ACT-CP-MA will include randomized controlled trials with ACT for chronic pain compared to control conditions for adults (≥ 18 years) with chronic pain (> 3 months). We will invite the authors of all eligible trials to share individual participant data. Outcomes will include standardized measures of pain interference, pain intensity, depression, anxiety, health-related quality of life, participants' rating of overall improvement, and ACT-related process variables. Using the Cochrane Collaboration's tool and GRADE, reviewers will independently check for risk of bias, quality of evidence, and strength of recommendations. In the individual participant data meta-analysis, we will use a one-step approach where participants are clustered with studies and data from all studies are modeled simultaneously. For analyses, we will use mixed-effects models. Additionally, we will employ a meta-analysis with aggregate data and compare the results of both meta-analyses.

DISCUSSION

This collaborative meta-analysis of individual participant data from randomized controlled trials of ACT for chronic pain versus control conditions will demonstrate how the known benefits of ACT for chronic pain vary across different subtypes of the chronic pain population. The results of the meta-analyses will be based on a comprehensive search of multiple databases and will help to inform future clinical trials and decision-making on the use of ACT in chronic pain and improve the quality, design, and reporting of future trials in this field.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42019120901.

Limitations in Using Multiple Imputation to Harmonize Individual Participant Data for Meta-Analysis

Individual participant data (IPD) meta-analysis is a meta-analysis in which the individual-level data for each study are obtained and used for synthesis. A common challenge in IPD meta-analysis is when variables of interest are measured differently in different studies. The term harmonization has been coined to describe the procedure of placing variables on the same scale in order to permit pooling of data from a large number of studies. Using data from an IPD meta-analysis of 19 adolescent depression trials, we describe a multiple imputation approach for harmonizing 10 depression measures across the 19 trials by treating those depression measures that were not used in a study as missing data. We then apply diagnostics to address the fit of our imputation model. Even after reducing the scale of our application, we were still unable to produce accurate imputations of the missing values. We describe those features of the data that made it difficult to harmonize the depression measures and provide some guidelines for using multiple imputation for harmonization in IPD meta-analysis.

Laparoscopic versus open resection for rectal cancer: An individual patient data meta analysis of randomized controlled trials

BACKGROUND AND AIMS

The role of laparoscopic rectal cancer resection remains controversial. Thus, we aimed to conduct a one-stage meta-analysis with reconstructed patient-level data using randomized trial data to compare long-term oncologic efficacy of laparoscopic and open surgical resection for rectal cancer.

METHODS

Medline, EMBASE and Scopus were searched for articles comparing laparoscopic with open surgery for rectal cancer. Primary outcome was disease free survival (DFS) while secondary outcome was overall survival (OS). One-stage meta-analysis was conducted using patient-level survival data reconstructed from Kaplan-Meier curves with Web Plot Digitizer. Shared-frailty and stratified Cox models were fitted to compare survival endpoints.

RESULTS

Seven randomized trials involving 1767 laparoscopic and 1293 open resections for rectal cancer were included. There were no significant differences between both groups for DFS and OS with respective hazard ratio estimates of 0.91 (95% CI: 0.78-1.06, p = 0.241) and 0.86 (95% CI:0.73-1.02, p = 0.090). Sensitivity analysis for non-metastatic patients and patients with mid and lower rectal cancer showed no significant differences in OS and DFS between both surgical approaches. In the laparoscopic arm, improved DFS was noted for stage II (HR: 0.73, 95% CI:0.54-0.98, p = 0.036) and stage III rectal cancers (HR: 0.74, 95% CI:0.55-0.99, p = 0.041).

CONCLUSIONS

This meta-analysis concludes that laparoscopic rectal cancer resection does not compromise long-term oncologic outcomes compared with open surgery with potential survival benefits for a minimal access approach in patients with stage II and III rectal cancer.

NETwork Meta-analysis Of Trials of Initial Oxygen in preterm Newborns (NETMOTION): A Protocol for Systematic Review and Individual Participant Data Network Meta-Analysis of Preterm Infants <32 Weeks' Gestation Randomized to Initial Oxygen Concentration for Resuscitation

BACKGROUND

Internationally recognized guidelines recommend the judicious use of low oxygen (21-30%), titrated to peripheral oxygen saturation targets, for the initiation of resuscitation of very and extremely preterm infants (<32 weeks' gestation). However, despite more than 10 randomized controlled trials on this question, the ideal initial oxygen concentration for this group of vulnerable infants remains uncertain.

AIMS

This study aims to assess the effect of various initial oxygen concentrations on (1) all-cause mortality, chronic lung disease, intraventricular hemorrhage, and retinopathy of prematurity; and (2) reaching the prescribed oxygen saturation targets by 5 min after birth, in preterm infants requiring resuscitation.

METHODS

We will conduct a systematic review and network meta-analysis using individual participant data. Studies of preterm infants <32 weeks' gestation, randomized to initial oxygen concentration, will be included. We will systematically search medical databases and trial registries for eligible studies (published or unpublished). Records will be screened by two independent reviewers, with conflicts resolved by the inclusion of a third reviewer. Identified initial oxygen concentrations will be grouped into the following nodes: low (≤30%), intermediate (60%), and high (≥90%) oxygen. A two-step random-effects contrast-based network meta-regression will be calculated to compare and rank different oxygen concentrations. Analyses will be intention-to-treat, with the primary outcome of all-cause mortality.

DISCUSSION

This is the first individual participant data network meta-analysis of initial oxygen concentrations for the resuscitation of preterm infants. This novel approach may address long-standing uncertainty regarding optimal oxygen supplementation practice for the resuscitation of preterm infants <32 weeks' gestation.

Predictors of the effects of treatment for shoulder pain: protocol of an individual participant data meta-analysis

BACKGROUND

Shoulder pain is one of the most common presentations of musculoskeletal pain with a 1-month population prevalence of between 7 and 26%. The overall prognosis of shoulder pain is highly variable with 40% of patients reporting persistent pain 1 year after consulting their primary care clinician. Despite evidence for prognostic value of a range of patient and disease characteristics, it is not clear whether these factors also predict (moderate) the effect of specific treatments (such as corticosteroid injection, exercise, or surgery).

OBJECTIVES

This study aims to identify predictors of treatment effect (i.e. treatment moderators or effect modifiers) by investigating the association between a number of pre-defined individual-level factors and the effects of commonly used treatments on shoulder pain and disability outcomes.

METHODS

This will be a meta-analysis using individual participant data (IPD). Eligible trials investigating the effectiveness of advice and analgesics, corticosteroid injection, physiotherapy-led exercise, psychological interventions, and/or surgical treatment in patients with shoulder conditions will be identified from systematic reviews and an updated systematic search for trials, and risk of bias will be assessed. Authors of all eligible trials will be approached for data sharing. Outcomes measured will be shoulder pain and disability, and our previous work has identified candidate predictors. The main analysis will be conducted using hierarchical one-stage IPD meta-analysis models, examining the effect of treatment-predictor interaction on outcome for each of the candidate predictors and describing relevant subgroup effects where significant interaction effects are detected. Random effects will be used to account for clustering and heterogeneity. Sensitivity analyses will be based on (i) exclusion of trials at high risk of bias, (ii) use of restricted cubic splines to model potential non-linear associations for candidate predictors measured on a continuous scale, and (iii) the use of a two-stage IPD meta-analysis framework.

DISCUSSION

Our study will collate, appraise, and synthesise IPD from multiple studies to examine potential predictors of treatment effect in order to assess the potential for better and more efficient targeting of specific treatments for individuals with shoulder pain.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42018088298.

Efficient two-step multivariate random effects meta-analysis of individual participant data for longitudinal clinical trials using mixed effects models

BACKGROUND

Mixed effects models have been widely applied in clinical trials that involve longitudinal repeated measurements, which possibly contain missing outcome data. In meta-analysis of individual participant data (IPD) based on these longitudinal studies, joint synthesis of the regression coefficient parameters can improve efficiency, especially for explorations of effect modifiers that are useful to predict the response or lack of response to particular treatments.

METHODS

In this article, we provide a valid and efficient two-step method for IPD meta-analyses using the mixed effects models that adequately addresses the between-studies heterogeneity using random effects models. The two-step method overcomes the practical difficulties of computations and modellings of the heterogeneity in the one-step method, and enables valid inference without loss of efficiency. We also show the two-step method can effectively circumvent the modellings of the between-studies heterogeneity of the variance-covariance parameters and provide valid and efficient estimators for the regression coefficient parameters, which are the primary objects of interests in the longitudinal studies. In addition, these methods can be easily implemented using standard statistical packages, and enable synthesis of IPD from different sources (e.g., from different platforms of clinical trial data sharing systems).

RESULTS

To assess the proposed method, we conducted simulation studies and also applied the method to an IPD meta-analysis of clinical trials for new generation antidepressants. Through the numerical studies, the validity and efficiency of the proposed method were demonstrated.

CONCLUSIONS

The two-step approach is an effective method for IPD meta-analyses of longitudinal clinical trials using mixed effects models. It can also effectively circumvent the modellings of the between-studies heterogeneity of the variance-covariance parameters, and enable efficient inferences for the regression coefficient parameters.

Individual participant data meta-analyses (IPDMA): data contribution was associated with trial corresponding author country, publication year, and journal impact factor

OBJECTIVES

The objectives were to determine the proportion of eligible randomized controlled trials (RCTs) that contributed data to individual participant data meta-analyses (IPDMAs) and explore associated factors.

STUDY DESIGN AND SETTING

IPDMAs with ≥10 eligible RCTs were identified by searching MEDLINE, EMBASE, CINAHL, and Cochrane May 1, 2015 to February 13, 2017. Mixed-effect logistic regression was used to identify factors associated with data contribution.

RESULTS

Of 774 eligible RCTs from 35 included IPDMAs, 517 (67%, 95% confidence interval [CI]: 63%-70%) contributed data. Compared to RCTs from journals with low-impact factors (0-2.4), RCTs from journals with higher impact factors were more likely to contribute data: impact factor 5.0-9.9, odds ratio [OR] 2.6, 95% CI: 1.37-4.86; impact factor: 10.0-19.9, OR: 5.7, 95% CI: 3.0-10.8; impact factor >20.0, OR: 4.6, 95% CI: 1.9-11.4. RCTs from the United Kingdom were more likely to contribute data than those from the United States (reference; OR: 2.4, 95% CI, 1.3-4.6). There was an increase in OR per publication year (OR: 1.05, 95% CI: 1.02-1.09).

CONCLUSION

The country where RCTs are conducted, impact factor of the journal where RCTs are published, and RCT publication year were associated with data contribution in IPDMAs with ≥10 eligible RCTs.

Risk of bias assessments in individual participant data meta-analyses of test accuracy and prediction models: a review shows improvements are needed

OBJECTIVES

Risk of bias assessments are important in meta-analyses of both aggregate and individual participant data (IPD). There is limited evidence on whether and how risk of bias of included studies or datasets in IPD meta-analyses (IPDMAs) is assessed. We review how risk of bias is currently assessed, reported, and incorporated in IPDMAs of test accuracy and clinical prediction model studies and provide recommendations for improvement.

STUDY DESIGN AND SETTING

We searched PubMed (January 2018-May 2020) to identify IPDMAs of test accuracy and prediction models, then elicited whether each IPDMA assessed risk of bias of included studies and, if so, how assessments were reported and subsequently incorporated into the IPDMAs.

RESULTS

Forty-nine IPDMAs were included. Nineteen of 27 (70%) test accuracy IPDMAs assessed risk of bias, compared to 5 of 22 (23%) prediction model IPDMAs. Seventeen of 19 (89%) test accuracy IPDMAs used Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2), but no tool was used consistently among prediction model IPDMAs. Of IPDMAs assessing risk of bias, 7 (37%) test accuracy IPDMAs and 1 (20%) prediction model IPDMA provided details on the information sources (e.g., the original manuscript, IPD, primary investigators) used to inform judgments, and 4 (21%) test accuracy IPDMAs and 1 (20%) prediction model IPDMA provided information or whether assessments were done before or after obtaining the IPD of the included studies or datasets. Of all included IPDMAs, only seven test accuracy IPDMAs (26%) and one prediction model IPDMA (5%) incorporated risk of bias assessments into their meta-analyses. For future IPDMA projects, we provide guidance on how to adapt tools such as Prediction model Risk Of Bias ASsessment Tool (for prediction models) and QUADAS-2 (for test accuracy) to assess risk of bias of included primary studies and their IPD.

CONCLUSION

Risk of bias assessments and their reporting need to be improved in IPDMAs of test accuracy and, especially, prediction model studies. Using recommended tools, both before and after IPD are obtained, will address this.

Sequential regression and simulation: a method for estimating causal effects from heterogeneous clinical trials without a common control group

BACKGROUND

The advent of clinical trial data sharing platforms has created opportunities for making new discoveries and answering important questions using already collected data. However, existing methods for meta-analyzing these data require the presence of shared control groups across studies, significantly limiting the number of questions that can be confidently addressed. We sought to develop a method for meta-analyzing potentially heterogeneous clinical trials even in the absence of a common control group.

METHODS

This work was conducted within the context of a broader effort to study comparative efficacy in Crohn's disease. Following a search of clnicaltrials.gov we obtained access to the individual participant data from nine trials of FDA-approved treatments in Crohn's Disease (N = 3392). We developed a method involving sequences of regression and simulation to separately model the placebo- and drug-attributable effects, and to simulate head-to-head trials against an appropriately normalized background. We validated this method by comparing the outcome of a simulated trial comparing the efficacies of adalimumab and ustekinumab against the recently published results of SEAVUE, an actual head-to-head trial of these drugs. This study was pre-registered on PROSPERO (#157,827) prior to the completion of SEAVUE.

RESULTS

Using our method of sequential regression and simulation, we compared the week eight outcomes of two virtual cohorts subject to the same patient selection criteria as SEAVUE and treated with adalimumab or ustekinumab. Our primary analysis replicated the corresponding published results from SEAVUE (p = 0.9). This finding proved stable under multiple sensitivity analyses.

CONCLUSIONS

This new method may help reduce the bias of individual participant data meta-analyses, expand the scope of what can be learned from these already-collected data, and reduce the costs of obtaining high-quality evidence to guide patient care.

Seizure outcomes in children with Sturge-Weber syndrome undergoing epilepsy surgery: An individual participant data meta-analysis

BACKGROUND

A subpopulation of patients with Sturge-Weber syndrome (SWS) develop medically intractable epilepsy. There is a paucity of literature on preoperative factors that predict postoperative seizure outcomes in these patients. An individual participant data meta-analysis (IPDMA) was performed to discern preoperative variables associated with favorable seizure outcomes in pediatric SWS patients undergoing epilepsy surgery.

METHODS

PubMed, Cochrane, Web of Science, and Scopus were independently queried following PRISMA guidelines. Studies that reported seizure outcomes in individual pediatric SWS patients were selected. Preoperative demographic variables and disease characteristics were recorded and evaluated in a time-to-event fashion via Cox regression and Kaplan-Meier analysis with log-rank test.

RESULTS

A total of 18 studies with 108 patients were included for meta-analysis. Median age at seizure onset was 4.5 months, and 85 patients (78.7%) were seizure-free at last follow-up (median: 72 months). On multivariable Cox regression, no variables were independent predictors of post-operative seizure freedom duration, including the extent of hemispheric resection. There were also no differences in time-to-seizure recurrence on Kaplan-Meier analysis when comparing those treated with hemispheric surgery and those with less than hemispheric surgery (p = 0.52).

CONCLUSION

This IPDMA showed that both resective and hemispheric epilepsy surgery achieve favorable and comparable seizure outcomes in pediatric SWS patients. The best available evidence using IPD suggests that resective surgery may be an appropriate alternative to hemispheric epilepsy surgery in well-selected patients. Prospective multi-institutional studies with greater follow-up are warranted to further investigate predictors of seizure outcome in pediatric SWS patients.

Predicting the treatment response of certolizumab for individual adult patients with rheumatoid arthritis: protocol for an individual participant data meta-analysis

BACKGROUND

A model that can predict treatment response for a patient with specific baseline characteristics would help decision-making in personalized medicine. The aim of the study is to develop such a model in the treatment of rheumatoid arthritis (RA) patients who receive certolizumab (CTZ) plus methotrexate (MTX) therapy, using individual participant data meta-analysis (IPD-MA).

METHODS

We will search Cochrane CENTRAL, PubMed, and Scopus as well as clinical trial registries, drug regulatory agency reports, and the pharmaceutical company websites from their inception onwards to obtain randomized controlled trials (RCTs) investigating CTZ plus MTX compared with MTX alone in treating RA. We will request the individual-level data of these trials from an independent platform (http://vivli.org). The primary outcome is efficacy defined as achieving either remission (based on ACR-EULAR Boolean or index-based remission definition) or low disease activity (based on either of the validated composite disease activity measures). The secondary outcomes include ACR50 (50% improvement based on ACR core set variables) and adverse events. We will use a two-stage approach to develop the prediction model. First, we will construct a risk model for the outcomes via logistic regression to estimate the baseline risk scores. We will include baseline demographic, clinical, and biochemical features as covariates for this model. Next, we will develop a meta-regression model for treatment effects, in which the stage 1 risk score will be used both as a prognostic factor and as an effect modifier. We will calculate the probability of having the outcome for a new patient based on the model, which will allow estimation of the absolute and relative treatment effect. We will use R for our analyses, except for the second stage which will be performed in a Bayesian setting using R2Jags.

DISCUSSION

This is a study protocol for developing a model to predict treatment response for RA patients receiving CTZ plus MTX in comparison with MTX alone, using a two-stage approach based on IPD-MA. The study will use a new modeling approach, which aims at retaining the statistical power. The model may help clinicians individualize treatment for particular patients.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration number pending (ID#157595).