In our study, we discovered that the majority of hip fracture patients experienced indoor falls during the daytime, with a peak incidence between 8:00 and 10:00 a.m. Further analysis of the characteristics of hip fracture patients who fell during the day and at night revealed that those who fell during the daytime exhibited significantly higher handgrip strength and a lower susceptibility to indoor falls compared to those who fell at night. Conversely, when we compared the differences in characteristics between hip fracture patients who fell indoors and outdoors, we found that only BMI and handgrip strength were the most significant predictors in a multiple variance analysis. Among patients who fell indoors, the primary causes of daytime falls were related to movement, while nighttime falls were predominantly associated with bathroom-related incidents. Among patients who fell outdoors, the leading cause was vehicular accidents, both during the daytime and nighttime.
Regarding the distribution of fall events during daytime and nighttime, our study observed that hip fractures induced by falls were more frequent during the daytime than at night among all participants. Unlike previous studies that struggled to identify specific times of day when falls are more likely to occur, our investigation considered various factors. Notably, fall risk assessment tools often include lower urinary tract symptoms[18–20], with nocturia, a common lower urinary symptom[21], frequently linked to falls. Previous research has suggested a potential association between the severity of nocturia and the risk of hip fractures[22], leading us to consider the likelihood of fall-induced hip fractures being more prevalent at night. While factors such as dark lighting and impaired eyesight contribute to an increased fall risk at night[23], our study results contradict this trend. We found that the majority of fracture events occurred during the daytime, particularly peaking between eight and nine o'clock. During this time, elderly individuals typically begin their morning routine, involving activities such as rising from bed, washing their face, or using the toilet. The primary causes of hip fractures in our study were related to movement within the house and getting up from bed. Sudden rising from bed is associated with orthostatic hypotension, a condition positively linked to falls in older adults[24]. In comparison to nighttime, people tend to engage in more daily activities during the daytime, leading to increased movement both indoors and outdoors. It becomes apparent that individuals are more susceptible to falls when active rather than peacefully sleeping in bed.
In the comparison between hip fracture patients who fell during the daytime and those who fell at night, our findings revealed that participants experiencing hip fractures at night had a lower BMI and grip strength, indicating a potential association with sarcopenia[25, 26]. Additionally, our study identified a significantly higher proportion of hip fractures related to bathroom incidents at night compared to during the day. Schellenberg et al. (2019) have highlighted the bathroom as a high-risk fall location[27]. Given that caregivers typically sleep at night, the risk of falls related to toilet activities increases during this period. Participants with incontinence face a heightened risk of falls, and Erdogan et al. (2019) demonstrated the association between sarcopenia and urinary incontinence[28]. This association may elucidate why participants who fell at night tended to have lower BMI and grip strength. Patients with sarcopenia are known to be more susceptible to hip fractures [29, 30]. Despite most of these patients being accompanied by caregivers during the day and unable to perform daily activities independently, the risk of fall incidents may escalate when they need to visit the bathroom without caregivers at night. Consequently, prioritizing fall prevention at night becomes crucial. Measures such as adequate lighting can contribute to preventing nighttime falls. The utilization of a remote light switcher can reduce the risk of falls when moving to turn on the light. Furthermore, installing a night light in the bathroom may also decrease the fall risk associated with nocturia[31].
Among all the participants, those who had hip fractures indoors appeared to be more fragile compared to those who had hip fractures outdoors. Engaging in outdoor activities contributes to the overall health of the elderly, as highlighted by Hiroyuki et al. (2010), who reported the health benefits of going outdoors[32]. According to their research, going outdoors once a week or less frequently is closely associated with impaired activities of daily living and increased hospitalization. Our findings align with this study, as participants who fell indoors showed significantly lower Barthel index, BMI, grip strength, and EQ5D compared to those who fell outdoors. However, when discussing the issue of falls, patients who go outdoors more frequently are exposed to the risk of traffic accidents. In fact, the most common cause of hip fractures in our study was related to vehicles, involving collisions with others or self-falls. This study was conducted in Taiwan, where motorcycle density in 2012 was significantly higher compared to the United Kingdom and the United States (1.5 persons per motorcycle in Taiwan compared to 47.4 and 118.7 persons per motorcycle, respectively)[33]. Motorcycle accidents stand out as one of the leading causes of mortality in many developing countries, and the dense population and narrow roads in Taiwan contribute to the high risk of incidents[34]. Participants who experienced hip fractures outdoors were mostly affected by external factors such as vehicles or other individuals. Despite being relatively healthier compared to those residing at home, these elderly individuals who go outside may face severe consequences from a traffic accident.
Falls represent a significant and preventable cause of injury, especially among the elderly, leading to severe consequences such as hip fractures, subdural hematomas, or even death[35]. A previous study outlined a 3-step process for fall prevention: (1) assessing fall risk, (2) developing a personalized prevention plan, and (3) consistently implementing the plan[36]. Based on the findings of our study, there is an opportunity to educate caregivers to be more attentive during high-risk moments. Getting up from bed emerged as a relatively high-risk movement in our study. Unlike hospitals, the beds of our participants lacked fall protection. Therefore, we recommend that the elderly install bed railings in their homes to enhance safe mobility. Given that moving within the house and falls related to the toilet were identified as high-risk timings after getting up, we suggest that if the elderly need to go to the bathroom, they should seek assistance from caregivers to prevent potential falls. The pathway to the bathroom is considered high-risk, regardless of whether it is daytime or nighttime. Elderly individuals can further enhance their safety by installing handrails on the walls and utilizing home fall prevention equipment[37].
In addition to physical facilities, mobile apps can play a crucial role in fall prevention. Community-dwelling elderly individuals typically do not use fall risk assessment tools in their daily lives, resulting in a lack of awareness of their high risk of falls until hospitalization. However, the development of an easily understandable fall prevention app for the elderly could make fall risk assessment more accessible in the community. Delbaere et al. (2021)[38] highlighted this possibility, acknowledging the widespread use of smartphones in recent years. If a mobile app can alert the elderly to potential fall risks and locations, home-based fall prevention would become more feasible. Implementing personalized fall prevention strategies requires a comprehensive understanding of an individual's health, lifestyle, and environmental factors. By integrating these considerations, healthcare professionals can collaborate with individuals to formulate effective and personalized fall prevention plans, ultimately enhancing the quality of life and reducing the risk of injury.
Limitations
Our study is subject to several limitations that should be considered in the interpretation of the findings. Firstly, while we obtained accurate fall times, not all patients were able to clearly articulate the causes of their falls. Some participants merely reported falling indoors without providing detailed information on the circumstances. This lack of specificity in reported fall causes may impact the precision of our categorized fall causes. Secondly, defining a control group posed challenges in our study. All participants were admitted to Wanfang Hospital for hip fractures, making it difficult to establish a control group from elderly individuals in the community who experienced falls without resulting in fractures or hospitalization. Consequently, we were unable to include these non-fracture fall events as a control group for comparing the characteristics of falls with and without fractures. Thirdly, hip fractures resulting from traffic accidents may differ in nature from other causes of falls. While most fractures in the elderly due to traffic accidents were characterized by low-energy mechanisms, our study lacked the ability to directly determine whether the fracture cause was due to a crush or a fall. Consequently, we opted to use hip fractures as an inclusion criterion without a precise medical definition for falls. This approach may have resulted in the inclusion of some fracture causes among our participants that deviate from the commonly understood concept of a "fall."