Evidence mapPaperPMID 42398988Full record

Observational studyBMJ open2026

Global inequities in the adoption of innovative clinical trial designs: a cross-sectional analysis of ClinicalTrials.gov.

Danila Azzolina, Vittorio Scisciola, Mariarita Stendardo, Domenico Iervolino, Emma Pedarzani, Rosanna Irene Comoretto, Martino Belvederi Murri, Dario Gregori

Abstract readObservational Study
In one paragraph

Observational study in BMJ open, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

0numbers the graph read from it
0cells of the map it votes in
0citing papers in PubMed
field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

0 citing papers in PubMed.

No citing paper in PubMed yet.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

8 authors.

Danila AzzolinaBiostatistics and Clinical Trial Methodology Unit,Clinical Research Center DEMeTra, Department of Translational Medical Science, University of Naples Federico II, University of Naples Federico II, Naples, Italy danila.azzolina@unife.it.ORCID http://orcid.org/0000-0002-8185-5742
Vittorio ScisciolaDepartment of Cardiac, Thoracic, Vascular Sciences and Public Health, University of Padova Unit of Biostatistics Epidemiology and Public Health, Padova, Italy.
Mariarita StendardoDepartment of Cardiac, Thoracic, Vascular Sciences and Public Health, University of Padova Unit of Biostatistics Epidemiology and Public Health, Padova, Italy.
Domenico IervolinoBiostatistics and Clinical Trial Methodology Unit,Clinical Research Center DEMeTra, Department of Translational Medical Science, University of Naples Federico II, University of Naples Federico II, Naples, Italy.
Emma PedarzaniResearch and Development Unit, University Hospital of Ferrara, Ferrara, Italy.
Rosanna Irene ComorettoDepartment of Public Health and Paediatrics, University of Turin, Turin, Italy.ORCID http://orcid.org/0000-0002-8601-1899
Martino Belvederi MurriDepartment of Neuroscience, University of Ferrara, Ferrara, Italy.
Dario GregoriDepartment of Cardiac, Thoracic, Vascular Sciences and Public Health, University of Padova Unit of Biostatistics Epidemiology and Public Health, Padova, Italy.ORCID http://orcid.org/0000-0001-7906-0580

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

introductionInnovative clinical trials, including adaptive and Bayesian designs, can improve efficiency and prioritise patient-centric approaches. Despite their recognised advantages, the global adoption of innovative clinical trial designs remains uneven, with substantial variation observed across socioeconomic and gender-related contexts. This study investigates the global distribution of innovative trial designs and their association with the Inequality-adjusted Human Development Index (IHDI) and Gender Inequality Index (GII).

methodsWe conducted a cross-sectional observational analysis of interventional studies registered on ClinicalTrials.gov between 1990 and 2024. Innovative trial designs were identified using a predefined keyword-based search applied to study description fields. Trials published before 1990 or lacking descriptive information were excluded. Country-level IHDI and GII data were obtained from the United Nations Human Development Reports and linked to trials by study location. Logistic regression with restricted cubic splines was used to model associations. Given the strong correlation between IHDI, penalised regression approaches were applied to ensure model stability.

resultsThe proportion of innovative trials increased after 2015, likely reflecting regulatory support and global initiatives. These trials were more common in regions with higher IHDI scores, particularly the Americas and Europe, while Africa showed the lowest prevalence. Higher GII values, indicating greater gender inequality, were associated with lower adoption of innovative designs. However, IHDI and GII were strongly correlated, suggesting that they capture closely related structural dimensions of development. Paediatric trials and non-industry-funded studies were more likely to adopt innovative designs, while gender-specific trials were less likely to do so.

conclusionsSignificant geographical and gender-related disparities exist in the global adoption of innovative clinical trials. More favourable structural contexts, characterised by higher socioeconomic development and lower gender inequality, were associated with greater adoption of innovative trial designs. However, due to the strong correlation between these indicators, their independent contributions cannot be disentangled, and findings should be interpreted as reflecting broader contextual environments rather than causal effects. Addressing these disparities requires targeted efforts to improve inclusivity and research capacity in underrepresented regions. Collaborative international initiatives and policy strategies may help promote more equitable access to innovative clinical trial methodologies.

Indexed as

Clinical Trials as TopicResearch DesignCross-Sectional StudiesFemaleHumansMaleSocioeconomic FactorsClinical TrialResearch DesignSexual and Gender MinoritiesSTATISTICS & RESEARCH METHODS

Identifiers

PMID42398988
PMCPMC13343026

What Socratic holds

Textmetadata
LicenceCC BY-NC
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the Socratic graph.