Background: Delirium is one of the most frequent, relevant, and increasing geriatric syndromes in hospitalized older adults. It is an indicator of poor prognosis, and its incidence increases with aging. It is a highly prevalent problem (between 10-56% of hospitalized elderly), underdiagnosed (32-66% undetected), with severe consequences and potentially preventable (between 30-40%). It is considered a priority health objective, as it is an indicator of elderly patient safety and an indicator of healthcare quality.

Objective: The objective of this study is to analyze whether a multicomponent nursing-led intervention reduces the incidence of delirium in frail older patients hospitalized in a medical unit.

Design: Pre-post quasi-experimental analytical study. Study setting: The study will be conducted in a polyvalent hospitalization unit at the Germans Trias i Pujol University Hospital during the 2023-2025 period.

Patients: A total of 158 patients will be needed, i.e., 79 for each group. Sampling: Consecutive intentional sampling based on inclusion and exclusion criteria.

Variables: Sociodemographic variables, delirium risk factors, daily presence of delirium using the CAM scale, and hospital stay duration, among others, will be collected.

Procedure: Patients will be selected upon admission, and the presence of delirium will be assessed daily using the CAM scale, with results recorded. Nursing staff will be trained on non-pharmacological measures for delirium prevention and a specific care plan. Subsequently, the second group of patients will receive these specific interventions, and the presence of delirium will be assessed daily using the CAM scale, with results recorded.

Data analysis: Descriptive and inferential analysis using the PSPP statistical package version 22. A significance level of 5% will be applied.

A pre-post quasi-experimental study will be conducted with a control group and an intervention group. Consecutive sampling will be performed purposively, using inclusion and exclusion criteria. A total of 158 patients are required, i.e., 79 per group. Granmo software was used to calculate the sample. An alpha risk of 0.05 was assumed, with a two-sided contrast and a beta risk of 0.2. The allocation ratio will be 1, and a 10% loss to follow-up rate and a 20% reduction in the incidence of delirium have been estimated.

Participants Patients over 70 years of age admitted to the HGTIP study units for conditions requiring hospitalization and who meet the established criteria. The inclusion and exclusion criteria for selecting participants for this study are shown in Table 1.

Recruitment of participants Candidates for the study will be identified daily by a member of the research team, who will check the computerized devices used to detect new admissions to the study unit. Those who meet the inclusion criteria will be invited to participate. The study will be explained to them, including their family members. If they agree, they will be provided with an informed consent form, which they will sign.

All patients admitted to the study unit who meet the established criteria will be included in the sample, until the required sample size is reached, estimated at approximately six months for the control group and another six months for the intervention group.

Intervention The study will be conducted in the multipurpose hospitalization unit of the Germans Trias i Pujol University Hospital (HUGTIP) during the period 2024-2025.

A. First, data will be collected to analyze the incidence of delirium in the unit prior to the intervention (baseline data/usual care).

B. The work to be performed will be communicated to the nursing and medical specialty teams of the multipurpose hospitalization unit and will be presented as an intervention to improve the quality of care.

C. A 1-hour in-person training program will be provided for each work shift (morning, afternoon, evening 1, and evening 2) to all professionals in the intervention unit.

D. Implementation of the multicomponent care plan specific to the prevention of delirium. (Annex 3).

E. The impact of training on clinical outcomes in the intervention unit will be analyzed.

F. Finally, the incidence of delirium will be analyzed, along with the specific care plan and training for professionals in preventing the syndrome.

Elements of the investigation A multicomponent care plan has been designed, comprising 12 intervention areas based on the main risk factors for delirium. For each area, different activities are proposed, as shown in Table 2. The intervention also includes a series of structural and scheduling modifications in the study unit, as specified in Table 3.

Furthermore, the training program that will be provided to all professionals in the intervention unit is based on strategies recommended by the Spanish Society of Geriatrics and Gerontology (SEGG) for the prevention of delirium.

The training will include the definition of delirium, symptoms of delirium that will help us recognize it early, its presentation (hyperactivity, hypoactivity, and mixed forms), training in the detection of delirium using the CAM scale, possible causes, predisposing and precipitating factors, the evolution of delirium once it has developed, prevention strategies, non-pharmacological measures, and the use of medications.

Implementation of the intervention The control group's data collection period will last approximately six months, or until the required sample size is reached. The unit's professionals will then be informed about the work to be performed, and their knowledge of the topic will be analyzed through a survey. The training program will then be delivered, and the care plan, along with any structural and scheduling modifications, will be implemented. Participants will be asked to complete the knowledge survey again to evaluate the training's impact. Finally, data will be collected from the intervention group for approximately another six months, or until the full sample size is reached.

Data collection Data collection will be conducted by the same professional from the research team within the first 24 to 48 hours of admission, based on medical records, nursing records, and information obtained directly from the patient and support staff.

Upon admission, sociodemographic data will be collected (age, sex, origin: home, intermediate care, residence, admission diagnosis and global status (Charlson, Pfeiffer, Barthel, Rockwood/CFS, PCC, ECA and presence of geriatric syndromes such as dysphagia, incontinence, falls, and other factors predisposing to delirium such as cognitive impairment, depression, pain, sensory disturbances, nutritional status, dehydration, delirium in previous admissions, psychoactive medication).

Daily data collection during admission includes the following variables: presence of delirium using the CAM scale, follow-up, correction of sensory disturbances, cognitive stimulation, mobilization, hydration and nutrition, psychoactive medications, and nighttime rest.

The variables to be collected for discharge are: days of admission, presence of delirium, days of duration of delirium, Pfeiffer, Barthel, destination: home, intermediate care, residence, psychoactive medication.

Inclusion Criteria:

• Patients >70 years old
• Conscious mental state. And one of the two criteria described below:
• Pfeiffer score on admission between 3-7 errors, according to the nursing assessment within the first 24 hours of admission to the ward, suggesting possible mild-moderate cognitive impairment.
• Any degree of diagnosed dementia, except GDS7.

Exclusion Criteria:

• Patients unable to communicate, with established aphasia, or with psychiatric illness.
• Patients with a language barrier.
• Patients transferred from other units.
• Terminal situation under palliative treatment.
• Patients who do not consent to participate