In this study, the construction of hip fracture patients with prolonged hospital stay risk prediction model, whether the model construction or the internal verification of the data have good sensitivity and specificity, indicating that the prediction effect of the model is good and the result is stable (AUC = 0.794). The model can directly reflect the risk factors of delayed hospitalization in the formula, which can not only predict the risk of delay in patients with clinical hip fracture, but also provide a basis for the follow-up medical staff to systematically evaluate the influencing factors of discharge delay. According to this nomogram, nurses can evaluate the hospitalization time of patients with hip fracture in advance, according to their preoperative waiting time, CCI, anemia, hypoproteinemia, Arteriosclerosis of lower limbs and other influencing factors, to speculate that patients may have delayed discharge risk, so as to shorten hospital stay, reduce the occurrence of postoperative complications, promote postoperative rehabilitation, and optimize the rational allocation of medical resources.
Preoperative Waiting Time
Preoperative waiting time greater than 48 hours is an influencing factor for delayed discharge of hip fracture patients. Consistent with the research results of Muhm et al. (Muhmet al, 2016), the waiting time before operation can affect the time of hospitalization. With the increase of patients' bed time before operation, the incidence of complications will increase, such as periprosthetic infection, pneumonia, urinary tract infection, stroke, myocardial infarction and septic shock, etc., and the deterioration of nutritional status will also lead to the decline of physical function, which will eventually lead to the extension of hospitalization time. (Heet al, 2020; Tang & Fu, 2017)。Sexson and Lehner et al (Sexson & Lehner, 1987) found that early surgery can relieve pain and improve mobility, and may reduce the risk of delirium and lung infection. Foreign literature shows that treatment within the first 24–72 hours of fracture can achieve lower mortality and postoperative complications (Gurger, 2019). It has been agreed that hip fracture patients should be operated as soon as possible, preferably within 48 hours after admission (Simunovicet al, 2010). Therefore, it is very important to give priority to the quick evaluation of hip fracture patients, and delay of operation should be avoided. Although it is best to perform early surgery within two days for patients with stable condition at the time of admission, for patients with complicated complications, surgery should be performed after preoperative optimization. Besides, besides the early operation emphasized in the guidelines, we also advocate early admission. Therefore, we suggest that health administrators and clinicians should strengthen the education and publicity of hip fracture, raise the awareness of the whole society on the severity of such severe cases, improve the timely admission rate, and finally improve the survival rate of hip fracture groups.
CCI
In this study, it was found that the hospitalization delay of patients with hip fracture with CCI ≥ 8 increased by 3.326 times. The CCI score includes the patient's age and various complications, reflecting the patient's overall health at the time of admission. Similar to the conclusions of this study, wei(Weiet al, 2019) found that the co-disease weight of elderly patients with hip fracture (based on age-adjusted CCI assessment) was associated with increased length of stay. A meta analysis also showed that there was a positive correlation between comorbid disease and length of stay of patients with hip fracture(Olthofet al, 2014). It is possible that patients with severe comorbidities may be more prone to complications and require multiple medication, so they will be given longer hospital stay for treatment and care(Charlesworthet al, 2015; Wonget al, 2022). In addition, these patients with a variety of chronic diseases lead to poor self-care ability, but also need a longer recovery period to return to their original self-care level.
Anemia
anemia is closely related to prolonged hospitalization in patients with hip fractures. Nissenholtz et al.(Nissenholtzet al, 2020)found that anemia has a significant effect on the length of stay of elderly patients with hip fracture. On the one hand, because anemic patients need to supplement blood volume and give allogeneic blood transfusion after operation, allogeneic blood transfusion will cause a variety of adverse reactions, affect the patient's immune system and blood coagulation system, and increase the incidence of complications (张 & 张, 2020) .On the other hand, the degree of postoperative anemia in patients with preoperative anemia of hip fracture is relatively severe, which affects the transport of nutrients in the fracture site, weakening the body's defense barrier and hindering the ability of self-repair, resulting in the invasion of pathogenic microorganisms. the final manifestation is an increase in the incidence of complications(Sequeiraet al, 2021). uncorrected anemia after hip fracture may hinder the functional recovery of patients with hip fracture and affect medical complications and length of stay (Sinclairet al, 2021) .
Hypoalbuminemia
Hypoalbuminemia is related to osteoporosis, fractures and falls, which slows down the early postoperative recovery of patients with fractures, increases the incidence of postoperative complications, prolongs the hospital stay, and causes a serious economic burden to patients' families. Hypoalbuminemia is closely related to postoperative hematoma formation, renal insufficiency and cardiovascular adverse events. It also directly affects wound healing by affecting fibroblast proliferation and collagen synthesis(Crosset al, 2014; Huanget al, 2013).Moreover, hypoproteinemia will lead to the decrease of patients' immune function and increase the incidence of wound infection and postoperative pneumonia(Rudasillet al, 2018). BOHL et al (Bohlet al, 2016) showed that preoperative hypoproteinemia can significantly prolong the hospital stay and increase the postoperative readmission rate by 40%. Similar studies have shown that preoperative hypoproteinemia can significantly increase the cost of total hip replacement patients and prolong the length of hospital stay(Rudasillet al, 2018).Therefore, monitoring the serum albumin level to find hypoalbuminemia in the early postoperative period and seeking an optimal scheme of nutritional supplement become a new way to solve the delay of hospitalization and optimize the operation quality of hip fracture patients.
Arteriosclerosis Of Lower Limbs
This study found that preoperative arteriosclerosis obliterans of lower limbs were significantly related to delayed discharge of hip fracture. Arteriosclerosis obliterans of lower limbs is characterized by thickening, calcification, thrombosis, etc. It is a chronic ischemic disease that leads to arterial stenosis or even occlusion. Patients with severe illness are characterized by persistent and severe pain, ulcer and necrosis of the affected limb or toe, which may lead to secondary infection and systemic toxemia. In addition, lower limb ASO will increase the prevalence of cardiovascular and cerebrovascular diseases. Foreign studies show that 40% of lower limb ASO patients suffer from coronary artery or cerebrovascular diseases, and 8.18% of patients suffer from three diseases at the same time (CAPRIE Steering Committee, 1996; Sartipyet al, 2018).Patients with hip fracture may be prolonged in hospital due to the above reasons.
Limitations: this study is a retrospective, single-center study, some indicators are not available; the inclusion of disease heterogeneity, underlying diseases, different etiology of primary diseases, these confounding factors to establish predictive models. The effectiveness of the prediction model still needs to be further verified by multicenter, prospective studies.