# Big Data Are Only as Good as the People and the Processes That Create Them: The EUROlinkCAT Success Story

Babak Khoshnood

► To cite this version:

Babak Khoshnood. Big Data Are Only as Good as the People and the Processes That Create Them: The EUROlinkCAT Success Story. Paediatric and Perinatal Epidemiology, 2025, 39 (3), pp.285-286. 10.1111/ppe.70014. inserm-05077128

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Submitted on 21 May 2025

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COMMENTARY

OPEN ACCESS

# Big Data Are Only as Good as the People and the Processes That Create Them: The EUROlinkCAT Success Story

Babak Khoshnood

<figure><img src="image_4.png" /></figure>

INSERM U1153, Obstetric, Perinatal, Paediatric Life Course Epidemiology - Center for Research on Epidemiology and Statistics Sorbonne Paris Cité,
Inserm, Université Paris Cité, Paris, France

**Correspondence:** Babak Khoshnood (babak.khoshnood@inserm.fr)

**Received:** 4 March 2025 | **Accepted:** 8 March 2025

**Funding:** The author received no specific funding for this work.

It would be short-sighted and archaic to deny that, with the increasing availability of big data and advancement in artificial intelligence, particularly machine learning and large language models, we have entered a new era of public health, medical research and scientific discovery. However, the current enthusiasm and, at times, even a certain degree of hype for these developments can also result in unintended negative consequences. This can happen if we are not careful during the planning and execution of big data construction, mainly when using and analysing administrative databases, whether by humans or machines.

The paper by Loane et al. [1] about the lessons learned from the EUROlinkCAT study is an excellent example of putting such concerns in a positive perspective. It underscores the added value of undertaking an ambitious linkage study that spans several different data sources in multiple countries. It also illustrates that one cannot underestimate the knowledge, experience, training and efforts required for creating and analysing high-quality, standardised linked big data that allow addressing multiple questions and objectives. The paper is a good example of what the economists call a 'positive externality' of the project, as the experiences of those who led the project and subsequently analysed the data have resulted in recommendations that benefit us all.

EUROlinkCAT was funded by the European Union's Horizon 2020 Research and Innovation programme to assess mortality and morbidity outcomes in children with congenital anomalies. It was a population-based cohort study of almost 100,000 children born between 1995 and 2014 with congenital

anomalies. Seventeen population-based European registries who are members of the European Surveillance of Congenital Anomalies (EUROCAT with the Central Registry at the Joint Research Centre in Italy, https://eu-rd-platform.jrc.ec.europa.eu/eurocat_en), including Belgium, Croatia, Denmark, Finland, France, Germany, Italy, Malta, Netherlands, Norway, Portugal, Spain, Ukraine and the United Kingdom, participated in the EUROlinkCAT study.

The EUROCAT registries use multiple data sources for case ascertainment and verification of the diagnoses with codes and data standardised according to EUROCAT guidelines. For the EUROlinkCAT study, routinely available data, including birth and death records, prescription and hospital discharge data, were harmonised to common data models. Central analysis scripts then produced aggregate tables for the analyses. Not all registries could provide the entire dataset, including hospital discharge and prescription data. Nevertheless, all 17 registries linked their standardised congenital anomalies data to national or regional mortality records. To date, 35 papers have been published on the basis of this data, which have partly informed the recommendations issued in the article by Loane et al.

The most important recommendation of Loane et al. [1] concerns terminations of pregnancy for foetal anomaly (TOPFA). These currently account for approximately 20% of all cases, and in certain registries, including ours in Paris, TOPFA accounts for almost one-third of all cases [2]. Hence, surveillance of the prevalence and assessments of the outcomes of congenital anomalies are incomplete unless TOPFA are included [3]. Loane et al. recommend that all TOPFA cases be recorded in the

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© 2025 The Author(s). Paediatric and Perinatal Epidemiology published by John Wiley & Sons Ltd.
mother's healthcare records. Moreover, they note that the cur-
rent WHO ICD-10 system is inadequate for recording TOPFA
following prenatal diagnosis of a congenital anomaly, and they
suggest ways of addressing this problem.

Another critical issue is that many national data systems cur-
rently lack a permanent, unique identification number assigned
at birth that would enable accurate linkage across multiple
healthcare and other databases. Inaccurate and heterogeneous
coding can be a significant challenge and barrier to using ad-
ministrative databases to address questions related to congeni-
tal anomalies. This is particularly problematic in cases such as
congenital heart defects [4, 5], which involve complex diagnoses
and numerous codes. For example, the preferred coding system
for congenital heart defects among paediatric cardiologists is
the extended version of the International Pediatric Congenital
Cardiac Code, which includes over 10,000 individual codes [6].
Another critical example is hypospadias, where coding has long
been recognised as a major issue for effective surveillance of this
anomaly [7]. To address these issues or to mitigate their impact,
the authors recommend using extended versions of the ICD-10
for coding rare anomalies or adapting other coding systems bet-
ter suited for characterising particularly complex anomalies.

Finally, national and European policies that prevent the release
of results based on a small number of children due to confiden-
tiality concerns severely hinder the visibility of rare anomalies,
the study of their causes, and their impact on individual pa-
tients and public health. The authors are correct in advocating
for adopting policies that allow the release of small numbers to
named, trusted researchers with disclosure agreements, thereby
enabling more effective surveillance and evaluation studies on
rare anomalies, especially in smaller registries or countries.

Administrative and other routinely available healthcare data
certainly offer advantages in terms of time and costs. For ex-
ample, the Système National des Données de Santé (SNDS) in
France has provided valuable data that have been published in a
variety of subjects [8–10]. These include post-marketing surveil-
lance studies of medication use and adverse effects, healthcare
costs and clinical care pathways.

Nonetheless, the EUROlinkCAT study and the paper by Loane
et al. show that significant barriers remain in using adminis-
trative databases for surveillance or research purposes in con-
genital anomalies. Although improvements are possible and
will come over time, there is a need for continued funding and
operation of population-based registries of congenital anomalies
that can provide consistent, high-quality, standardised data over
the long term. This is the only feasible means to safeguard ef-
fective surveillance of congenital anomalies, assess teratogens,
including medications and environmental factors, and evaluate
preventive health policies and the impact of changes in medical
and surgical care in this field. Otherwise, it would be unrealis-
tic to think that stakeholders and policymakers will have access
to the necessary information for devising and evaluating health
policies related to congenital anomalies, many of which are clas-
sified as Rare Diseases by the European Union.

In these disconcerting times of rather indiscriminate public
spending cuts, it is essential to remember that you get what you
pay for—and indeed, there is no free lunch.

Author Contributions

The author takes full responsibility for this article.

Disclosure

The author has nothing to report.

Conflicts of Interest

The author declares no conflicts of interest.

Data Availability Statement

The author has nothing to report.

References

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2. I. Monier, S. Hachem, F. Goffinet, A. Martinez-Marin, B. Khoshnood, and N. Lelong, "Population-Based Surveillance of Congenital Anomalies Over 40 Years (1981-2020): Results From the Paris Registry of Congenital Malformations (remaPAR)," *Journal of Gynecology Obstetrics and Human Reproduction* 53 (2024): 102780.

3. B. Khoshnood, "Selection Bias in Studies of Birth Defects Among Livebirths: Much Ado About Nothing?," *Paediatric and Perinatal Epidemiology* 34 (2020): 665-667.

4. H. Dolk, M. Loane, and E. Garne, "Congenital Heart Defects in Europe: Prevalence and Perinatal Mortality, 2000 to 2005," *Circulation* 123 (2011): 841-849.

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7. H. Dolk, M. Vrijheid, J. E. Scott, et al., "Toward the Effective Surveillance of Hypospadias," *EnvironHealth Perspect* 112, no. 3 (2004): 398-402, https://doi.org/10.1289/ehp.6398.

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9. M. Lassalle, M. Zureik, and R. Dray-Spira, "Proton Pump Inhibitor Use and Risk of Serious Infections in Young Children," *JAMA Pediatrics* 177 (2023): 1028-1038.

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