BackgroundFrailty is a geriatric syndrome with repercussions on health, disability, and dependency.ObjectivesTo assess health resource use and costs attributable to frailty in the aged population.MethodsA population-based observational longitudinal study was performed, with follow-up from January 2018 to December 2019. Data were obtained retrospectively from computerized primary care and hospital medical records. The study population included all inhabitants aged ≥ 65 years ascribed to 3 primary care centres in Barcelona (Spain). Frailty status was established according to the Electronic Screening Index of Frailty. Health costs considered were hospitalizations, emergency visits, outpatient visits, day hospital sessions, and primary care visits. Cost analysis was performed from a public health financing perspective.ResultsFor 9315 included subjects (age 75.4 years, 56% women), frailty prevalence was 12.3%. Mean (SD) healthcare cost in the study period was €1420.19 for robust subjects, €2845.51 for pre-frail subjects, €4200.05 for frail subjects, and €5610.73 for very frail subjects. Independently of age and sex, frailty implies an additional healthcare cost of €1171 per person and year, i.e., 2.25-fold greater for frail compared to non-frail.ConclusionsOur findings underline the economic relevance of frailty in the aged population, with healthcare spending increasing as frailty increases.