Contacting authors to retrieve individual patient data: study protocol for a randomized controlled trial

Pharmacokinetic analysis across studies to drive knowledge-integration: A tutorial on individual patient data meta-analysis (IPDMA)

Answering challenging questions in drug development sometimes requires pharmacokinetic (PK) data analysis across different studies, for example, to characterize PKs across diverse regions or populations, or to increase statistical power for subpopulations by combining smaller size trials. Given the growing interest in data sharing and advanced computational methods, knowledge integration based on multiple data sources is increasingly applied in the context of model-informed drug discovery and development. A powerful analysis method is the individual patient data meta-analysis (IPDMA), leveraging systematic review of databases and literature, with the most detailed data type of the individual patient, and quantitative modeling of the PK processes, including capturing heterogeneity of variance between studies. The methodology that should be used in IPDMA in the context of population PK analysis is summarized in this tutorial, highlighting areas of special attention compared to standard PK modeling, including hierarchical nested variability terms for interstudy variability, and handling between-assay differences in limits of quantification within a single analysis. This tutorial is intended for any pharmacological modeler who is interested in performing an integrated analysis of PK data across different studies in a systematic and thorough manner, to answer questions that transcend individual primary studies.

Comparative efficacy and complications of long-acting and intermediate-acting insulin regimens for adults with type 1 diabetes: an individual patient data network meta-analysis

OBJECTIVE

To examine the comparative efficacy and complications of long-acting and intermediate-acting insulin for different patient characteristics for type 1 diabetes mellitus (T1DM).

DESIGN

Systematic review and individual patient data (IPD) network meta-analysis (NMA).

DATA SOURCES

MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trials were searched through June 2015.

ELIGIBILITY CRITERIA

Randomised controlled trials (RCTs) on adults with T1DM assessing glycosylated haemoglobin (A1c) and severe hypoglycaemia in long-acting and intermediate-acting insulin regimens.

DATA EXTRACTION AND SYNTHESIS

We requested IPD from authors and funders. When IPD were not available, we used aggregate data. We conducted a random-effects model, and specifically a one-stage IPD-NMA for those studies providing IPD and a two-stage IPD-NMA to incorporate those studies not providing IPD.

RESULTS

We included 28 RCTs plus one companion report, after screening 6680 titles/abstracts and 205 full-text articles. Of the 28 RCTs, 27 studies provided data for the NMA with 7394 participants, of which 12 RCTs had IPD on 4943 participants. The IPD-NMA for A1c suggested that glargine once daily (mean difference [MD]=-0.31, 95% confidence interval [CI]: -0.48 to -0.14) and detemir once daily (MD=-0.25, 95% CI: -0.41 to -0.09) were superior to neutral protamine Hagedorn (NPH) once daily. NPH once/two times per day improved A1c compared with NPH once daily (MD=-0.30, 95% CI: -0.50 to -0.11). Results regarding complications in severe hypoglycaemia should be considered with great caution due to inconsistency in the evidence network. Accounting for missing data, there was no evidence of inconsistency and long-acting insulin regimens ranked higher regarding reducing severe hypoglycaemia compared with intermediate-acting insulin regimens (two-stage NMA: glargine two times per day SUCRA (Surface Under the Cumulative Ranking curve)=89%, detemir once daily SUCRA=77%; one-stage NMA: detemir once daily/two times per day SUCRA=85%). Using multiple imputations and IPD only, complications in severe hypoglycaemia increased with diabetes-related comorbidities (regression coefficient: 1.03, 95% CI: 1.02 to 1.03).

CONCLUSIONS

Long-acting insulin regimens reduced A1c compared with intermediate-acting insulin regimens and were associated with lower severe hypoglycaemia. Of the observed differences, only glargine once daily achieved a clinically significant reduction of 0.30%. Results should be interpreted with caution due to very low quality of evidence.

PROSPERO REGISTRATION NUMBER

CRD42015023511.

Many researchers were not compliant with their published data sharing statement: a mixed-methods study

OBJECTIVES

The objective of the study was to analyze researchers' compliance with their data availability statement (DAS) from manuscripts published in open-access journals with the mandatory DAS.

STUDY DESIGN AND SETTING

We analyzed all articles from 333 open-access journals published during January 2019 by BioMed Central. We categorized types of the DAS. We surveyed corresponding authors who wrote in the DAS that they would share the data. Consent to participate in the study was sought for all included manuscripts. After accessing raw data sets, we checked whether data were available in a way that enabled reanalysis.

RESULTS

Of 3556 analyzed articles, 3416 contained the DAS. The most frequent DAS category (42%) indicated that the data sets are available on reasonable request. Among 1792 manuscripts in which the DAS indicated that authors are willing to share their data, 1669 (93%) authors either did not respond or declined to share their data with us. Among 254 (14%) of 1792 authors who responded to our query for data sharing, only 123 (6.8%) provided the requested data.

CONCLUSION

Even when authors indicate in their manuscript that they will share data upon request, the compliance rate is the same as for authors who do not provide the DAS, suggesting that the DAS may not be sufficient to ensure data sharing.

A review of methods for addressing components of interventions in meta-analysis

Many healthcare interventions are complex, consisting of multiple, possibly interacting, components. Several methodological articles addressing complex interventions in the meta-analytical context have been published. We hereby provide an overview of methods used to evaluate the effects of complex interventions with meta-analytical models. We summarized the methodology, highlighted new developments, and described the benefits, drawbacks, and potential challenges of each identified method. We expect meta-analytical methods focusing on components of several multicomponent interventions to become increasingly popular due to recently developed, easy-to-use, software tools that can be used to conduct the relevant analyses. The different meta-analytical methods are illustrated through two examples comparing psychotherapies for panic disorder.

Exercise-based cardiac rehabilitation for chronic heart failure: the EXTRAMATCH II individual participant data meta-analysis

BACKGROUND

Current national and international guidelines on the management of heart failure (HF) recommend exercise-based cardiac rehabilitation (ExCR), but do not differentiate this recommendation according to patient subgroups.

OBJECTIVES

(1) To obtain definitive estimates of the impact of ExCR interventions compared with no exercise intervention (control) on mortality, hospitalisation, exercise capacity and health-related quality of life (HRQoL) in HF patients; (2) to determine the differential (subgroup) effects of ExCR in HF patients according to their age, sex, left ventricular ejection fraction, HF aetiology, New York Heart Association class and baseline exercise capacity; and (3) to assess whether or not the change in exercise capacity mediates for the impact of the ExCR on final outcomes (mortality, hospitalisation and HRQoL), and determine if this is an acceptable surrogate end point.

DESIGN

This was an individual participant data (IPD) meta-analysis.

SETTING

An international literature review.

PARTICIPANTS

HF patients in randomised controlled trials (RCTs) of ExCR.

INTERVENTIONS

ExCR for at least 3 weeks compared with a no-exercise control, with 6 months' follow-up.

MAIN OUTCOME MEASURES

All-cause and HF-specific mortality, all-cause and HF-specific hospitalisation, exercise capacity and HRQoL.

DATA SOURCES

IPD from eligible RCTs.

REVIEW METHODS

RCTs from the Exercise Training Meta-Analysis of Trials for Chronic Heart Failure (ExTraMATCH/ExTraMATCH II) IPD meta-analysis and a 2014 Cochrane systematic review of ExCR (Taylor RS, Sagar VA, Davies EJ, Briscoe S, Coats AJ, Dalal H, et al. Exercise-based rehabilitation for heart failure. Cochrane Database Syst Rev 2014;4:CD003331).

RESULTS

Out of the 23 eligible RCTs (4398 patients), 19 RCTs (3990 patients) contributed data to this IPD meta-analysis. There was a wide variation in exercise programme prescriptions across included studies. Compared with control, there was no statistically significant difference in pooled time-to-event estimates in favour of ExCR, although confidence intervals (CIs) were wide: all-cause mortality had a hazard ratio (HR) of 0.83 (95% CI 0.67 to 1.04); HF-related mortality had a HR of 0.84 (95% CI 0.49 to 1.46); all-cause hospitalisation had a HR of 0.90 (95% CI 0.76 to 1.06); and HF-related hospitalisation had a HR of 0.98 (95% CI 0.72 to 1.35). There was a statistically significant difference in favour of ExCR for exercise capacity and HRQoL. Compared with the control, improvements were seen in the 6-minute walk test (6MWT) (mean 21.0 m, 95% CI 1.57 to 40.4 m) and Minnesota Living with Heart Failure Questionnaire score (mean -5.94, 95% CI -1.0 to -10.9; lower scores indicate improved HRQoL) at 12 months' follow-up. No strong evidence for differential intervention effects across patient characteristics was found for any outcomes. Moderate to good levels of correlation (R ² _trial > 50% and p > 0.50) between peak oxygen uptake (VO₂peak) or the 6MWT with mortality and HRQoL were seen. The estimated surrogate threshold effect was an increase of 1.6 to 4.6 ml/kg/minute for VO₂peak.

LIMITATIONS

There was a lack of consistency in how included RCTs defined and collected the outcomes: it was not possible to obtain IPD from all includable trials for all outcomes and patient-level data on exercise adherence was not sought.

CONCLUSIONS

In comparison with the no-exercise control, participation in ExCR improved the exercise and HRQoL in HF patients, but appeared to have no effect on their mortality or hospitalisation. No strong evidence was found of differential intervention effects of ExCR across patient characteristics. VO₂peak and 6MWT may be suitable surrogate end points for the treatment effect of ExCR on mortality and HRQoL in HF. Future studies should aim to achieve a consensus on the definition of outcomes and promote reporting of a core set of HF data. The research team also seeks to extend current policies to encourage study authors to allow access to RCT data for the purpose of meta-analysis.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42014007170.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

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.

Contacting of authors modified crucial outcomes of systematic reviews but was poorly reported, not systematic, and produced conflicting results

OBJECTIVES

The objective of the study was to assess the prevalence, the reporting quality, the need, and the consequences of contacting of authors by Cochrane reviewers to obtain additional information for their reviews.

STUDY DESIGN AND SETTING

Cross-sectional study and survey on all new Cochrane intervention reviews published between January 1, 2016 and January 31, 2017.

RESULTS

The cross-sectional study found that reviewers had contacted or had tried to contact studies to obtain additional information in 73.4% (234/319) of reviews but reported poorly on the methods, outcomes, and consequences of this procedure. Most eligible studies in the reviews were poorly reported, but few reviewers 21.2% (65/306) reported that they had contacted these studies. The survey showed that risk of bias scores, Grading of Recommendations, Assessment, Development and Evaluation scores, the summary primary or secondary outcomes, and the summary effect size of the primary outcome of the review were changed as a consequence of contacting of authors. Thirty-five of one hundred and thirty (26.9%) reviews scored opposite outcomes for the same question in the cross-sectional study compared with the survey.

CONCLUSIONS

Our findings on contacting of authors by Cochrane reviewers showed relevant shortcomings in the current standards and transparency of Cochrane reviews. These shortcomings can compromise the validity and reproducibility of these reviews and affect a wide audience.

Short email with attachment versus long email without attachment when contacting authors to request unpublished data for a systematic review: a nested randomised trial

OBJECTIVE

Systematic reviews often rely on the acquisition of unpublished analyses or data. We carried out a nested randomised trial comparing two different approaches for contacting authors to request additional data for a systematic review.

PARTICIPANTS

Participants were authors of published reports of prevention or treatment trials in stroke in which there was central adjudication of events. A primary and secondary research active author were selected as contacts for each trial.

INTERVENTIONS

Authors were randomised to be sent either a short email with a protocol of the systematic review attached ('Short') or a longer email that contained detailed information and without the protocol attached ('Long'). A maximum of two emails were sent to each author to obtain a response. The unit of analysis was trial, accounting for clustering by author.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome was whether a response was received from authors. Secondary outcomes included time to response, number of reminders needed before a response was received and whether authors agreed to collaborate.

RESULTS

88 trials with 76 primary authors were identified in the systematic review, and of these, 36 authors were randomised to Short (trials=45) and 40 to Long (trials=43). Responses were received for 69 trials. There was no evidence of a difference in response rate between trial arms (Short vs Long, OR 1.10, 95% CI 0.36 to 3.33). There was no evidence of a difference in time to response between trial arms (Short vs Long, HR 0.91, 95% CI 0.55 to 1.51). In total, 27% of authors responded within a day and 22% of authors never responded.

CONCLUSIONS

There was no evidence to suggest that email format had an impact on the number of responses received when acquiring data for a systematic review involving stroke trials or the time taken to receive these responses.