Introduction：Delirium is a prevalent psychiatric disorder observed in the Intensive Care unit(ICU) hat; often aggravates patients; overall health status, extends the duration of mechanical ventilation, prolongs ICU stays, and causes persistent or long-term cognitive impairment. A plethora of studies have indicated that the frequency, duration, and severity of delirium during hospitalization are significant risk factors for cognitive impairment in patients following transfer from the ICU. However, existing research has predominantly focused on cross-sectional analyses without delving into the influencing factors among patient subgroups. Consequently, the aim of this study is to employ the Latent Growth Curve Model (LGCM) and the Latent Class Growth Model (LCGM) model to analyze the trajectory of cognitive development and influencing factors of patients with delirium in the ICU one year after discharge.

Methods and analysis：This prospective study aims to investigate the trajectory of cognitive level variations of patients with delirium in ICU for one year. It is planned to recruit 240 participants and gather comprehensive data including general demographics, disease-related information, scores from the Minimum Mental State Examination, Hospital Anxiety and Depression Scale, and the Pittsburgh Sleep Quality Index. All data will be followed up using the same schedule on the day of transfer, 1 month after transfer, 3 months after transfer, 6 months after transfer and 1 year after transfer. Ultimately, the investigators will employ Latent Growth Curve Model and Latent Class Growth Model to analyze the trajectory of cognitive changes and identify potential categories, in addition to utilizing logistic regression modeling to explore influencing factors. The results of this study provide a theoretical framework for the clinical implementation of precision nursing interventions within this demographic, so as to prevent and reduce the decline of cognitive function and improve the quality of life of patients.

A prospective longitudinal cohort study will be conducted in the ICU of a tertiary grade-A hospital in Guizhou Province. The study aims to recruit 240 patients diagnosed with ICU delirium, who were carefully selected based on predefined inclusion and exclusion criteria (Inclusion and exclusion criteria were as follows). The study is anticipated to commence in September 2024 and conclude in May 2026.

The inclusion criteria are:

1. Patients diagnosed with delirium by Confusion Assessment Model for Intensive Care Unit.
2. Age ≥ 18 years old.
3. Length of stay in ICU ≥24h.
4. Patients were able to complete the questionnaire by themselves or with the cooperation of their family members.5. Patients or family members gave informed consent and participated in the survey voluntarily.

The exclusion criteria are:

1. Previously diagnosed with dementia.
2. Mental illness or history of mental illness.
3. Suffering from traumatic brain injury, cerebrovascular disease, stroke, cranial surgery, intracranial infections, and other conditions that may affect cognitive function.
4. Presence of visual, hearing or communication impairments. Collection of general and disease-related information: trained staff assess ICU patients for delirium at the conclusion of the daily shift. Patients with delirium are included in the study, with the severity of delirium evaluated using the confusion assessment method for the ICU-7 scale. The date and time of delirium will be recorded, and the assessment will be carried out on a daily basis until the patient is transferred out of the ICU. Delirium-related information will be compiled after the patient's transfer out, and clinical subphenotypes of delirium will be ascertained using the RASS score , precipitant subphenotypes of delirium based on the patient's symptoms, severity of delirium based on the confusion assessment method for the ICU-7 scale, and the duration and frequency of occurrence of delirium based on the date and time of the recorded tracing. In addition, written informed consent will be obtained from the participants or their families prior to the commencement of data collection.

Follow-up data collection: at the time of patient transfer, the research team remains in contact with the participants and tracks their whereabouts and rehabilitation outcomes after discharge. Follow-up visits are conducted on the day of transfer (T1), 1 month after transfer (T2), 3 months after transfer (T3), 6 months after transfer (T4), and 1 year after transfer (T5) (see Table 4). Members of our study team will provide one-on-one contact with patients via WeChat video or face-to-face follow-up. Participants or family members are deemed disengaged if they are unwilling to cooperate in the study.

Outcome measures: cognitive level, anxiety and depression level and sleep status of delirium patients after discharge. Minimum Mental State Examination, Hospital Anxiety and Depression Scale and Pittsburgh sleep quality index will be used for measurement.

The inclusion criteria are:

1. Patients diagnosed with delirium by CAM-ICU.
2. Age ≥ 18 years old.
3. Length of stay in ICU ≥24h.
4. Patients were able to complete the questionnaire by themselves or with the cooperation of their family members.
5. Patients or family members gave informed consent and participated in the survey voluntarily.

The exclusion criteria are:

1. Previously diagnosed with dementia.
2. Mental illness or history of mental illness.
3. Suffering from traumatic brain injury, cerebrovascular disease, stroke, cranial surgery, intracranial infections, and other conditions that may affect cognitive function.
4. Presence of visual, hearing or communication impairments.

ICU patients