The goal of this observational study is to determine how often orthostatic hypotension and postprandial hypotension occur in adults aged 65 years and older who are hospitalized in internal medicine departments.

Orthostatic hypotension is defined as an excessive drop in blood pressure after standing up from a lying or sitting position. Postprandial hypotension is an excessive drop in blood pressure that occurs after eating a meal. These conditions can increase the risk of falls, fainting, loss of independence, and other health problems in older adults.

The main questions this study aims to answer are:

• How common orthostatic hypotension and postprandial hypotension are in hospitalized adults aged 65 years and older.
• Whether these conditions are associated with medication use, chronic diseases, and geriatric syndromes (such as frailty, cognitive impairment, and functional decline).

Participants will:

• have blood pressure measured while lying down and standing
• have blood pressure measured after a meal
• undergo a comprehensive geriatric assessment, including evaluation of functional status, cognitive function, frailty, mobility, and nutritional status
• provide information about medications and medical history
• be followed for up to 12 months to record outcomes such as falls, syncope, hospitalization, and death

Orthostatic hypotension (OH) and postprandial hypotension (PPH) are common manifestations of impaired blood pressure regulation in older adults. Orthostatic hypotension is defined as a decrease in systolic blood pressure of at least 20 mmHg or diastolic blood pressure of at least 10 mmHg within 3 minutes of standing. Postprandial hypotension refers to a clinically significant decline in blood pressure occurring after a meal. Both conditions are associated with adverse outcomes in older adults, including falls, syncope, functional decline, loss of independence, and increased mortality. Despite their clinical importance, OH and PPH are frequently underrecognized in hospitalized patients.

This prospective observational cohort study aims to determine the prevalence of orthostatic hypotension and postprandial hypotension in adults aged 65 years and older hospitalized in internal medicine departments at the University Medical Centre Ljubljana. The study will also examine associations between OH and PPH and factors such as medication use, comorbidities, and geriatric syndromes.

Participants will undergo standardized orthostatic blood pressure measurements and assessment of postprandial blood pressure changes. In addition, a comprehensive geriatric assessment will be performed, including evaluation of functional status (activities of daily living), cognitive function, frailty, mobility, and nutritional status, using standardized instruments (e.g., Barthel Index, Timed Up and Go test, Mini Nutritional Assessment - Short Form, and Clinical Frailty Scale), as well as validated cognitive tests. Information on medications, comorbidities, and clinical characteristics will be collected through clinical assessment and review of medical records.

Participants will be followed for up to 12 months to assess clinically relevant outcomes, including falls, syncope, functional decline, rehospitalization, and mortality.

The findings of this study are expected to improve understanding of the epidemiology and clinical impact of orthostatic and postprandial hypotension in hospitalized older adults and may contribute to improved recognition and management of these conditions in clinical practice.

Inclusion Criteria:

• Age 65 years or older
• Hospitalization in internal medicine departments at the University Medical Centre Ljubljana
• Duration of hospitalization ≥48 hours
• Hemodynamic stability confirmed by the treating physician
• Ability to participate in study procedures
• Ability to stand (with or without assistive devices for walking)
• Written informed consent obtained

Exclusion Criteria:

• Medical condition preventing study procedures (e.g., need for continuous supine position)
• Inability to provide informed consent
• Refusal to participate
• Severe cognitive impairment or delirium
• Acute critical illness requiring intensive treatment
• Participation in another clinical study that could affect safety or study outcomes

Hospitalized adults aged 65 years and older admitted to internal medicine departments at the University Medical Centre Ljubljana.

Individual participant data will not be shared due to data protection and privacy regulations.