Clinical research with older adults. Characteristics and trends in the European Union

Aging causes progressive physiological and pathological changes in all organs of the body, which determines the use of medications indicated in each particular case. This is a primary reason for the representation of older adults in clinical trials because the behavior of drugs in a changing body tends to become unpredictable. Emerging evidence indicates an underrepresentation of older adults in randomized clinical trials, which is not exclusive to certain countries but is widespread worldwide. This underrepresentation of older patients in clinical trials results in a lack of high-quality data for the care of this population, which is especially relevant given that older adults have, compared to their younger counterparts, a higher incidence of disease-related morbidities, take more medications, and are responsible for more drug-related adverse events. The problem is exacerbated by the increasing life expectancy among people over 65 in most countries around the world and by the fact that nine-tenths of people over 65 are taking some form of medication, a proportion that rises even further among those over 75. We conducted an analysis using data from the CTIS, the European Union’s Clinical Trials Information System (data extracted on March 7, 2025), corresponding to clinical trials involving people over 64 years of age that are authorized or currently ongoing. The total number of trials is 5,967, representing 78.5% of the total for all ages (7,600, from 0 to over 64 years). The number of ongoing clinical trials with completed recruitment and selection processes totals 1,405, of which 39 (2.8%) had 1,000 or more participants, and only half (50.4%) included 100 or more participants. The majority (43%) of these studies investigate neoplastic diseases, with a significant majority being cardiovascular diseases (7.5%), the nervous system (6.6%), the immune system (6.6%), and the digestive system (6.0%). Considering the study phase, 75% of the studies correspond to Phase II (exploratory) and III (confirmatory). Finally, the EU countries with the highest number of clinical trials currently are France (35.1% of those authorized and 47.1% of those currently ongoing), Spain (32.3% and 47.7%), Germany (22.8% and 39.2%), and Italy (25.5% and 37.3%), although the majority of these are multinational studies. Half (50.4%) are promoted by a pharmaceutical company, although a significant portion (35.7%) is also promoted by hospitals and clinics.