The specific aim of the study will be to investigate the incidences and risk factors for postoperative delirium (POD) after hip fracture surgery in elderly patients aged ≥ 65 years in five different Southeast and East Asian countries.

The secondary objectives are outlined below:

1. To investigate factors in the hospital environments, such as noise levels, ambient lighting, nursing ratios, ward bedding and climate control, that contribute to similarities and/or differences in POD occurrences in different countries and health systems
2. To investigate patient factors, such as disease burden, mental health, education levels, and socioeconomic factors, that contribute to similarities and/or differences in POD occurrences in different countries and health systems
3. To quantify the direct and indirect costs, as well as resource utilization, resulting from the development of POD in each country

Hip fractures encompass all fractures of the upper (proximal) part of the thigh bone (femur). They are commonly divided into two types: intracapsular fractures, which represent those that occur within or proximal to the attachment of the hip joint capsule to the femur, and extracapsular, which represent fractures occurring below or distal to the attachment of the hip joint capsule.

Hip fractures are common in elderly people with an annual incidence rate estimated as 1.29/1000 person-years in men and 2.24/1000 person-years in women. It is the most common condition requiring physical rehabilitation in older adults. The majority (>95%) of people undergo hip surgery following hip fracture. The location of the fracture, stability, and degree of comminution (number of pieces the bone breaks into) determine which operative procedure should be used to repair the hip fracture. The aim of surgery, irrespective of the type of operation, is to reduce pain, facilitate early weight-bearing mobility to improve outcome, and facilitate independence in activities of daily living, such as bathing, dressing, and continence. However, hip fracture is associated with significant pain and loss of independence and function. Although 33-37% of patients return to their prior level of function within six months including those needing assistance, only 24% of people are independently mobile six months after hip fracture.

A major complication in elderly hip fracture patients is POD, with an incidence rate varying from 13% to 65%. POD after hip surgery was significantly associated with non-home discharge disposition, and higher odds of 30-day readmissions and 30-day mortality. POD is also associated with poor outcomes, such as lower rates of immediate postoperative weight bearing, increased pressure sores, and poorer recovery of activities of daily living. In addition, a recent meta-analysis showed that POD after hip surgery translates into long-term cognitive disease burden, by increasing the risk of incident dementia and cognitive decline by a marked odds ratio of 8.957.

No strong evidence exists regarding the treatment of delirium. Several studies performed on delirium prevention in hip fracture patients have described the use of care bundles such as orthogeriatric care and comprehensive geriatric care as an effective potential treatment for this patient group, although the evidence remains weak. However, Inouye et al stated that in the general geriatric population, 30% to 40% of the delirium episodes could be prevented by addressing modifiable risk factors.

Previous studies in the five Asian countries involved in this study show that the incidence of POD after hip fracture surgery varied greatly between countries and within countries: 12.8-27.9% in Japan, 5.07-51.3% in Korea, 13.4-45% in Thailand and 7.2% in Singapore. The incidence of POD in Malaysia can be estimated at 9-12% as reported in the recent HIP Attack trial. However, these studies were heterogenous in terms of patient selection, study methodology and hospital systems. These variations make it difficult to draw a direct comparison regarding the incidence of POD amongst Asian countries and to Western cohorts. Furthermore, the cost of POD to patients and institutions, both direct and indirect, is very poorly defined in Asian countries.

Inclusion Criteria:

• Ability to provide informed consent
• Elderly patients aged 65 years and above
• Scheduled to undergo elective or emergency hip fracture surgery

Exclusion Criteria:

• History of psychiatric disease
• Baseline cognitive impairment or dementia (MOCA score < 24)
• Illiterate (unable to read or write with local language)
• Active history of substance abuse
• Has a second surgery planned within 5 days of index surgery
• Non-resident of Singapore
• Significant hearing and/or speech impairment
• Planned for admission into the intensive care unit after surgery

Elderly patients aged 65 and above scheduled to undergo hip fracture surgery