Our study successfully established a predictive model using machine learning methods for assessing falls risk in patients with chronic obstructive pulmonary disease (COPD) in Chinese communities. In this study, we incorporated eight variables with statistical significance obtained from community background data, specifically: Memory_disease, Cardiology, Hyperlipidemia, Hypertension, Gender, Sleeping_time _at_night, ADL_score, and Age. The results yielded a predictive model with relatively high accuracy.
This study found that older age is associated with an increased risk of falls in community-dwelling COPD patients. Research has shown that advanced age is a known risk factor for falls, with nearly 30% of individuals aged 65 and older in the community and 50% of those residing in nursing homes experiencing falls annually.[15] .The main reasons for this are as follows: firstly, as individuals age, sensory perception decreases, balance deteriorates, reaction times slow, and musculoskeletal changes, such as muscle fiber atrophy, lead to reduced muscle strength and function. Prolonged bed rest in patients can further decrease muscle strength and function with increased length of hospital stay, thereby increasing the likelihood of falls upon getting out of bed[16]. From an aging perspective, age-related changes in the frontal cortex can lead to cognitive decline, reduced attention and executive function, as well as decreased sensory processing, all of which may contribute to falls[17, 18]. Therefore, older COPD patients are more prone to falls. Moreover, COPD itself can lead to respiratory difficulties, fatigue, and limitations in physical activity, which can further impact endurance and mobility. Older COPD patients may have more severe symptoms and greater impairments in physical functioning. Additionally, elderly COPD patients may have comorbidities such as cardiovascular disease, metabolic disorders, and psychiatric conditions, which can also increase the risk of falls [19].
We know that community-dwelling COPD patients often have multiple comorbidities. This study found a close association between the risk of falls in community-dwelling COPD patients and memory diseases, cardiology, hyperlipidemia, and hypertension. Research indicates a positive correlation between chronic health conditions and falls[20]. Possible reasons for this relationship include exacerbation of COPD due to comorbidities, side effects of long-term use of multiple medications, and the comorbidities themselves increasing the risk of falls. Patients with comorbid cardiovascular diseases may experience falls due to reduced cardiac output leading to inadequate brain perfusion. COPD patients with comorbid cardiovascular diseases are at increased risk of falls due to the likelihood of angina or myocardial infarction. A cross-sectional study found that coronary heart disease is the third most common chronic disease associated with increased risk of falls after depression and arthritis[2, 21]. However, the high prevalence of coronary heart disease among COPD patients[22], indicates an increased risk of falls in this population. An analysis of adults hospitalized for cardiovascular disease (including myocardial infarction, atrial fibrillation, and heart failure) found that over 60% of individuals have a moderate to high risk of falling regardless of age[23]. Another study found that community-dwelling adults self-reporting 4 to 5 types of cardiovascular disease (hypertension, angina, heart attack, congestive heart failure, heart murmur, or arrhythmia) recalled falling or fainting more frequently in the past year than those with fewer CVDs, suggesting that older adults with cardiovascular diseases are more prone to falls[24]. Hyperlipidemia leads to atherosclerosis and other cardiovascular diseases, impacting patients' mobility and balance, thereby increasing the likelihood of falls [25]. Additionally, hyperlipidemia can cause poor systemic circulation, leading to symptoms such as dizziness during walking, further increasing the risk of falls. However, there is limited literature on this topic, warranting further research. Memory diseases affect patients' cognitive function and spatial orientation, increasing their risk of falls[26]. Research has shown that individuals with memory diseases are more likely to overlook environmental hazards, have unstable movements, and easily lose balance in daily life, making them more prone to falls [27]. These factors increase the likelihood of fall accidents and negatively impact physical health and quality of life.
This study found a significant association between nighttime sleep duration and falls in COPD patients.Research has shown that adults over the age of 65 who sleep less than 6 hours at night are at an increased risk of falls [28]. This could be due to the important role that sleep plays in regulating the body's metabolic and hormone levels. Short periods of sleep (< 6 hours) can decrease the secretion of growth hormone (GH), insulin-like growth factor-1 (IGF-1), and testosterone, while also leading to an increase in cortisol levels[29]. Decreased secretion of growth hormone, IGF-1, and testosterone can hinder muscle protein synthesis, increase breakdown of skeletal muscle protein, and elevated cortisol levels can result in muscle loss, thus increasing the risk of falls. Moreover, poor sleep quality and insufficient sleep duration in middle-aged and older adults are also associated with an increased risk of white matter changes in the brain, stroke, and osteoporosis. Finally, short sleep duration may increase levels of inflammatory markers, including tumor necrosis factor-alpha and interleukin-6, leading to early inflammation[30]. This chronic inflammatory state may result in decreased muscle mass and strength, decreased gait speed, and an increased rate of falls. Excessive sleep (> 8 hours) in older adults is closely associated with the occurrence of fall-related fractures, as research has found that prolonged nighttime sleep has a detrimental impact on falls[31]. It has been reported that individuals who sleep longer have poorer physiological and cognitive functions, both of which are directly related to higher rates of falls [31]. However, the same study also found that longer nighttime sleep may have a protective effect against falls and fall-related fractures in middle-aged and older adults, but it should be limited to no more than 9 hours per night. Therefore, both excessively long and short nighttime sleep durations are associated with the occurrence of falls.
This study found that among community-dwelling COPD patients who experienced falls, males had a significantly higher prevalence compared to females. Males were more likely than females to engage in behaviors such as smoking, alcohol consumption, and high levels of physical activity, which are all factors associated with an increased risk of falls. This is consistent with existing research[32]. However, in contrast to the findings of Xu et al.[33] that suggest females are more prone to falls, it is possible that females may exhibit greater caution in their actions than males, leading to a heightened fear of falling and inadvertently increasing fall prevention awareness, resulting in fewer falls among female COPD patients. Other studies have reported a higher risk of falls among female patients compared to males[34], possibly due to factors such as limited daily activity range, lower muscle mass, and poorer balance in females [35]. Additionally, female patients may experience more adverse reactions or complications during treatment, which could also contribute to an increased risk of falls. Future research could further explore the relationship between patient gender and other factors, and strive to optimize models for more accurate prediction of fall risk among patients. Targeted interventions tailored to gender differences could help patients reduce the risk of falls and improve their quality of life. Despite findings indicating a higher likelihood of falls among females, the role of gender as a risk factor for falls remains controversial[36].
Our research has found that elderly COPD patients are more prone to falls as they age and experience a decrease in their activities of daily living[34]. Over 45% of individuals aged 60 and above have reported difficulties in performing daily activities[37]. More than half of falls occur during routine activities such as eating, walking, dressing, toileting, and climbing stairs, which require more effort or are more challenging than usual. If patients attempt to complete these activities alone in such circumstances, it inadvertently increases the risk of falling [38]. Some researchers have indicated that implementing preventive measures to address falls in the elderly can enhance their quality of life, reduce dependency on activities of daily living [39].
Limitation
However, it is important to acknowledge the limitations of our study. Firstly, the absence of universally accepted criteria for including or excluding tartar as a factor is a notable constraint. Secondly, the sample size used in the study was relatively small, thereby restricting the applicability of the results. Despite achieving a high level of agreement in the reproducibility analysis of the training and test sets, there is a possibility of errors arising from segmentation uncertainties. Additionally, certain variables such as alcohol consumption and diabetes were not taken into account in the study's design. It is evident that further longitudinal or prospective case-control studies are imperative to elucidate the correlation between risk factors in COPD patients in the community and the incidence of falls.