(Vienna, 07 March 2024) In a recent study, researchers from the Complexity Science Hub and MedUni Vienna are analysing the entire health trajectory of almost nine million people in Austria for the first time. They identify critical points at which disease progression drifts apart significantly - with serious consequences for the lives of patients and for the healthcare system. The study was published in the specialist journal "npj Digital Medicine".
The world's population is ageing at an increasing rate. According to the WHO, one in six people will be over 60 by 2023. By 2050, the number of people over 60 is expected to have doubled - to 2.1 billion. "With increasing age, the risk of several, often chronic diseases occurring simultaneously, i.e. multimorbidity, also increases significantly," explains lead author Elma Dervic from the Complexity Science Hub. In view of the demographic changes we are facing, this poses a number of challenges. On the one hand, multimorbidity reduces the quality of life of those affected. On the other hand, it places a massive additional burden on healthcare and social systems, which poses major challenges for many countries. "That's why we want to find out which typical disease progressions occur in multimorbid patients from birth to death and which critical moments in their lives significantly characterise their further course. Because this provides clues for very early and personalised prevention strategies," says Dervic, explaining the motivation for the study.
The team of researchers from the Complexity Science Hub and the Medical University of Vienna analysed all hospital stays in Austria between 2003 and 2014, around 44 million in total. In order to gain useful information from this amount of data, the scientists constructed multi-layered networks. Each age group of ten years represents a layer. The points within these layers represent diagnoses. This enabled the researchers to recognise correlations between different diseases in different age groups - for example, how often obesity, high blood pressure and diabetes occur together in 20-29-year-olds and which diseases then follow with an increased risk in later decades of life. In this way, they identified 1,260 different disease trajectories (618 in women and 642 in men) over a period of up to 70 years. "On average, one of these disease trajectories includes nine different diagnoses, which illustrates how common multimorbidity actually is," emphasises Dervic.
Critical points in time
Research is focussing primarily on those 70 courses in which patients have similar diagnoses at a younger age, but which then develop into significantly different courses with different disease patterns. "If these courses differ significantly later in life in terms of severity and the corresponding hospitalisations required, despite a similar initial situation, this is a critical moment that plays an important role in prevention," says Dervic.
One example: if men between the ages of 20 and 29 suffer from sleep disorders, the model shows two typical progressions. In course A, metabolic diseases such as diabetes mellitus, obesity and lipometabolic disorders occur years later. Progression B, on the other hand, leads to movement disorders, among other things. This may indicate that organic sleep disorders could be an early marker for the risk of developing neurodegenerative diseases such as Parkinson's disease.
"So if someone suffers from sleep disorders at a young age, this can be a critical event. With this knowledge, doctors have the opportunity to be alert," explains Dervic. The results of the study show that patients with course B spend nine fewer days in hospital in their 20s, but 29 more days in their 30s and also suffer from more additional diagnoses. As sleep disorders are on the rise, it not only makes a difference to those affected, but also to the healthcare system.
The same applies when girls between the ages of ten and nineteen suffer from high blood pressure. While some develop metabolic diseases later on, others develop chronic kidney disease in their twenties, which can lead to increased mortality at a young age. This is clinically relevant above all because high blood pressure in childhood is also increasing worldwide, which is closely linked to the fact that childhood obesity is becoming increasingly common.
This means that there are specific progressions that require special attention and targeted monitoring. "With this knowledge gained from real data, doctors can begin to monitor various diseases more closely decades before serious problems occur and take targeted, personalised, preventive measures," explains Dervic. This should not only help to reduce the burden on healthcare systems, but also improve patients' quality of life.
Publication: npj Digital Medicine
Unraveling cradle-to-grave disease trajectories from multilayer comorbidity networks;
Elma Dervic, Johannes Sorger, Liuhuaying Yang,Michael Leutner, Alexander Kautzky, Stefan Thurner, Alexandra Kautzky-Willer, Peter Klimek
DOI: 10.1038/s41746-024-01015-w