The incidence of preoperative frailty is high among elderly patients undergoing abdominal surgery. The findings of this study revealed that the incidence of preoperative frailty in this patient population was 15.7%. This finding aligns with the 15.4% reported incidence among elderly patients undergoing breast cancer surgery reported by Lu et al., (2023) but is lower than the 26.67% reported in a study of elderly patients scheduled for elective abdominal surgery conducted by Niu et al., (2023). One possible explanation for this difference is that the study by Niu et al. included patients aged 65 years and older, whereas our study included patients aged 60 years and older. Previous research has also indicated that advanced age is associated with a greater likelihood of experiencing preoperative frailty (Zhang et al., 2023). Furthermore, this study utilized convenience sampling, potentially resulting in constraints on the sample’s representativeness and, consequently, influencing the accuracy of frailty incidence assessment to a certain degree. Despite the inherent limitations associated with this sampling approach, our study retains a degree of reference significance and offers valuable insights for future research endeavors aimed at assessing frailty incidence through the application of more suitable sampling methodologies.

Notably, our study also found that a weight loss of ≥ 5% within 1 year or less was a major manifestation of preoperative frailty in elderly patients undergoing abdominal surgery, with an incidence rate of 37.3%.The elevated percentage underscores the likelihood that rapid weight loss could be a crucial indicator of preoperative frailty among elderly patients scheduled for abdominal surgery. This observation may be associated with factors previously identified in studies, including malnutrition and the progression of chronic diseases, further highlighting the complexity and multifactorial nature of frailty in elderly surgical patients. Conversely, Zhang et al., (2022) and Lu et al., (2023) observed fatigue as the primary manifestation. This discrepancy could be attributed to the fact that their studies primarily focused on tumor patients, who often exhibit persistent cancer-related fatigue from diagnosis onward (Peng and Chen 2022). Notably, not all elderly patients included in our study had tumors and abdominal surgery often carries a risk of malnutrition (Jia, et al. 2011; Sorensen et al. 2008). Body weight is a commonly used and straightforward indicator for assessing nutritional status, reflecting an individual's overall nutritional well-being (Yu, 2010). Therefore, it is reasonable to assume that elderly patients with preoperative frailty who undergo abdominal surgery are more likely to experience weight loss. Future research can further explore the specific mechanisms between weight changes and preoperative frailty, as well as how to delay or reverse this process through interventions, providing a scientific basis for perioperative management of elderly patients undergoing abdominal surgery.

A high incidence of comorbid chronic diseases has been identified as a significant associated factor for preoperative frailty among elderly patients undergoing abdominal surgery. Our study revealed that patients with three or more comorbid chronic diseases exhibited a markedly elevated risk of preoperative frailty, specifically 2.694 times higher, compared to those with 0–2 chronic diseases. This notable correlation underscores the importance of the chronic disease burden in predicting the likelihood of frailty, demonstrating a clear trend of increasing frailty risk as the number of diseases increases. Our findings align with previous research conducted by MA (2018). Furthermore, a study by Han Yuzhu and colleagues (2019) reported a 1.63-fold increase in frailty risk for each additional chronic disease, which supports our observations. Regarding potential underlying mechanisms, it is plausible that the cumulative impact of multiple chronic diseases leads to a substantial decline in the overall physiological reserve capacity of elderly patients. Each chronic disease independently contributes to the deterioration of one or more bodily systems, thereby compromising the body's inherent self-regulatory and compensatory mechanisms. Preoperative frailty, as a manifestation of this widespread functional decline, becomes increasingly prevalent under the combined pressure of these multiple stressors. Moreover, patients with a higher number of comorbid chronic diseases often require a broader range of medications. The complex interactions between these medications can exacerbate the burden on the liver and kidneys (Han et al., 2019), potentially disrupting essential physiological functions such as appetite and sleep, further compromising patients’ resilience. Therefore, chronic medication use and the accumulation of potential adverse effects are pivotal factors contributing to the heightened association with preoperative frailty. Furthermore, chronic diseases frequently impair digestive and absorptive functions, hindering patients' ability to obtain adequate nutritional support. As the number of chronic diseases increases, so do the nutritional and metabolic impairments, creating an environment conducive to malnutrition. In turn, malnutrition not only weakens patients' immune defenses but also undermines muscle strength and other vital physiological parameters, thereby strengthening the association with preoperative frailty. Additionally, elderly patients with a heavier chronic disease burden often struggle with heightened psychological stress, with negative emotions triggering physiological sequelae such as reduced sleep quality, further exacerbating their physical and mental well-being. This vicious cycle may intensify the association with preoperative frailty. In light of these findings, clinical practice should prioritize the assessment of frailty status during preoperative evaluations for elderly abdominal surgery patients with three or more chronic diseases. By implementing individualized interventions tailored to mitigate the association with preoperative frailty, we can enhance patients’ surgical tolerance and improve postoperative recovery outcomes. It is crucial to acknowledge that our study does not establish causality but provides valuable insights into the association between chronic disease burden and preoperative frailty, guiding future research endeavors and clinical decision-making.

The findings of this study indicated an association between preoperative frailty and the risk of malnutrition in elderly patients undergoing abdominal surgery, which was consonant with prior research. A study conducted by Cao Ting et al., (2019) further supports this observation, demonstrating that elderly patients with preoperative malnutrition have a 2.656-fold increased likelihood of experiencing frailty compared to those with normal nutritional status. Nutritional status emerges as a pivotal factor influencing frailty, with malnutrition identified as a significant biological contributor to its development and progression. Conversely, frailty may also influence nutritional status, potentially exacerbating malnutrition (Wang et al., 2021). Albumin (Alb), a traditional nutritional biomarker, occupies a central position in this context. Inadequate protein and energy intake can lead to decreased serum Alb levels, which may subsequently result in reduced skeletal muscle mass, an elevated risk of osteoporosis, fractures, falls, and other adverse events, potentially accelerating the onset of frailty. Nutritional guidelines underscore the importance of increasing protein intake to improve the nutritional status of frail elderly patients, as this may aid in mitigating the risks associated with frailty (Elderly Nutrition Support Group of the Extracorporeal and Enteral Nutrition Branch of the Chinese Medical Association, 2020). Based on the outcomes of nutritional assessments, clinical healthcare professionals should provide health education and early intervention to elderly patients scheduled for abdominal surgery who have preoperative malnutrition or are at risk of malnutrition. They should counsel patients to augment their protein intake, enhance their nutritional status, and increase muscle mass, which may assist in reducing the risk of frailty (Li et al., 2023).

The findings of this study established an association between limited ability to perform activities in daily living (ADL) and preoperative frailty in patients, which concurred with previous research. Cao Ting et al., (2019), in their investigation of preoperative frailty among elderly patients undergoing abdominal surgery, similarly found that those with impaired ADL exhibited a 4.088-fold increased incidence of frailty compared to those with intact ADL prior to surgery. Furthermore, Fried et al., (2001) demonstrated that elderly individuals classified as frail or prefrail often exhibit a decline in self-care abilities. Elderly patients with limited ADL capacity may encounter challenges such as ambulatory impairments, difficulties with stair climbing, and an increased risk of falls, which suggest reduced activity tolerance and mobility limitations. These mobility restrictions may further lead to decreased motivation for physical exercise, limited engagement in daily activities, muscle weakness, and diminished cardiopulmonary function, potentially elevating the risk of frailty. Therefore, nurses should be vigilant in assessing the ADL of elderly patients prior to surgery and, when their condition and physical status permit, encourage them to engage in appropriate physical function exercises. By maintaining their daily living activities, patients may be able to mitigate the occurrence of frailty, thereby reducing surgical risks and improving postoperative recovery outcomes. It is crucial to emphasize that this study does not establish causality but rather highlights associations; hence, any interventions proposed should be implemented with caution, and further research is warranted to fully understand the relationships and potential causal mechanisms involved.