Researchers at the Complexity Science Hub (CSH) analyzed 13 million inpatient hospital stays involving around 4 million individuals in Austria: Although about 20% of the population in Austria does not hold Austrian citizenship, this group accounts for only 9.4% of hospital patients and 9.8% of total hospital nights.
An estimated 300 million people – about 3.6 percent of the global population – are international migrants. Yet studies consistently show that migrants access healthcare services less frequently than native populations. For example, a global analysis of data from 84 countries between 2018 and 2021 found that in only half of them do migrants have equal access to healthcare.
In Austria, where one in five residents is a migrant, the question of how migrants engage with the healthcare system is of particular urgency. It was also the starting point for a recent study conducted by researchers at CSH and the Medical University of Vienna, which was published in the Journal of Migration and Health.
"Reliable data on medical care for migrants can help identify access barriers and gaps in healthcare provision, improve quality of life, enable efficient resource planning, and shape stereotypical debates based on facts," says Elma Dervic , researcher at CSH and lead author of the study.
FEWER HOSPITAL STAYS
The researchers examined data on around 13 million hospital stays in Austria between 2015 and 2019. Their results show that people who live in Austria but do not hold Austrian citizenship have significantly lower hospitalization rates. This applies to all nationalities except German citizens, who record the most hospital stays per capita and whose usage patterns resemble those of Austrians – both in terms of the hospital departments they are admitted to and their primary and overall diagnoses. All other nationalities show clear differences.
For men, the hospitalization rate per capita is highest among Austrians (0.235), followed by Slovaks (0.229) and Italians (0.226). North Macedonians (0.125), Croatians (0.131), and Serbians (0.133) have the fewest hospital stays. The hospitalization rate reflects the likelihood that a person of a given nationality will be admitted to hospital within one year. For instance, the rate for Turkish women in 2019 was calculated by dividing the number of female Turkish patients by the number of female Turkish residents living in Austria.
For women (excluding pregnancy-related stays), Germans (0.223) have the most hospital stays – ahead of Syrian (0.209) and Austrian women (0.207). The hospitalization rate is lowest among Russian women (0.109), North Macedonian women (0.118), and Serbian women (0.126).
MORE READMISSIONS
While overall hospitalization rates are lower among migrants than Austrians, readmission rates (how often patients are readmitted to the hospital within one year) are higher. "This could indicate that people without Austrian citizenship go to the hospital later in the course of an illness," explains Dervic.
Among men, Syrians have the highest readmission rate – followed by Russians and Afghans. Only Hungarians have a significantly lower rate than Austrians.
Among women (excluding pregnancy-related stays), the readmission rate is highest for Afghan women – followed by Serbian, German, and Bulgarian women. It is lowest among North Macedonian women. However, Turkish, Italian, Hungarian, Romanian, Croatian, and Bosnian women also have readmission rates below those of Austrian women.
"HEALTHY MIGRANT" OR ACCESS BARRIERS
Readmission rates could be particularly revealing in order to gain insights into the healthcare of migrants - and to understand why they are hospitalized less frequently, according to the researchers.
Firstly, there is the so-called "Healthy Migrant Effect." It refers to the idea that people who migrate to another country tend to be relatively healthy and often young – meaning they arrive in better health than the average population. "If this effect were the main reason for the lower hospitalization rates among migrants in Austria, we would also expect their readmission rates to be low," explains Dervic. Moreover, the researchers controlled for age in their analysis, meaning they compared only individuals within the same age groups.
Secondly, however, if access barriers (such as language or cultural barriers) play a role in the lower hospitalization rates, migrants might still suffer from significant health issues but avoid hospitals until much later. This would then result in higher readmission rates, as illnesses are more advanced at the time of the initial hospital visit.
For example, people from Hungary, Romania and – in the case of women – Turkey show lower readmission rates, which might be consistent with the "Healthy Migrant Effect." Patients from Russia, Serbia and – in the case of men – Turkey show higher readmission rates, which is more indicative of barriers to access.
MEN LESS LIKELY TO BE HOSPITALIZED
Male patients of all nationalities have lower hospitalization rates than women of the same nationality. For certain nationalities, the differences are particularly pronounced: 32% more Turkish women than Turkish men were admitted to the hospital, 26% more among Germans, and 28% more Serbian women than Serbian men.
DIFFERENT DIAGNOSES
When comparing initial admissions, clear differences emerged between Austrian and non-Austrian patients. For example, non-Austrians were admitted less frequently to general and vascular surgery, but more frequently to internal medicine departments (including cardiology and nephrology), hematology, oncology, and radiology – which could be a sign that these people more often suffer from chronic or severe illnesses, according to the researchers. Additionally, psychiatric diagnoses were made less frequently among non-Austrians. This suggests that mental illnesses are underdiagnosed among migrants," explains Peter Klimek from CSH and MedUni Vienna. All of these differences were substantially smaller among patients with German citizenship.
"Our study shows that the different use of the Austrian healthcare system by people of different nationalities cannot be explained solely by the "Healthy Migrant Effect" or cultural barriers," says Klimek. "Rather, the use of the healthcare system by migrant population groups must be differentiated by nationality, as there are obviously different patterns of use in different groups. Future measures should specifically facilitate access - especially to outpatient care - for example through better translation services or orientation aids in the healthcare system."
ABOUT THE STUDY
The study " Healthcare Utilization Patterns Among Migrant Populations: Increased Readmissions Suggest Poorer Access. A Population-Wide Retrospective Cohort Study " by Elma Dervic, Ola Ali, Carola Deischinger, Rafael Prieto-Curiel, Rainer Stütz, Ellenor Mittendorfer-Rutz and Peter Klimek was recently published in Journal of Migration and Health (doi: 10.1016/j.jmh.2025.100340).
ABOUT THE COMPLEXITY SCIENCE HUB
The Complexity Science Hub (CSH) is Europe's research center for the study of complex systems. We derive meaning from data from a range of disciplines – economics, medicine, ecology, and the social sciences – as a basis for actionable solutions for a better world.
CSH members are Austrian Institute of Technology (AIT), BOKU University, Central European University (CEU), Graz University of Technology, Interdisciplinary Transformation University Austria (IT:U), Medical University of Vienna, TU Wien, University of Continuing Education Krems, Vetmeduni Vienna, Vienna University of Economics and Business, and Austrian Economic Chambers (WKO).
