Risk Factors for Discharge to Rehabilitation Among Hip Fracture Patients
Length of stay (LOS) drives costs for hip fracture patients. One factor that affects LOS is delayed transfer of patients to rehabilitation centers. It is therefore imperative that orthopedists have a mechanism for identifying which patients require rehabilitation services after surgery.
We conducted a study to identify patient risk factors that are significantly associated with discharge to rehabilitation. Using 2011 ACS-NSQIP (American College of Surgeons National Surgical Quality Improvement Program) data, we prospectively analyzed the cases of 4815 patients who underwent hip fracture surgery and had discharge information available. Discharge location, surgery type, patient demographics, 32 patient comorbidities, and 7 operative factors were identified in these patients. Fisher exact tests were used to determine which patient factors were significantly associated with discharge to rehabilitation.
Of the 4815 patients, 80.3% were discharged to rehabilitation and 19.7% to home. After multivariable analysis, age over 65 years, female sex, dialysis, prior percutaneous coronary intervention, hypertension, general anesthesia, and ASA (American Society of Anesthesiologists) class higher than 2 had higher odds of discharge to rehabilitation, and DNR (do not resuscitate) status had higher odds of discharge to home.
This study was the first to determine which factors predicted discharge to rehabilitation in hip fracture patients. Knowing these risk factors provides orthopedists with a mechanism that can be used to identify which patients require rehabilitation after surgery, thereby facilitating transfer and potentially decreasing LOS and associated costs.
Surgery type significantly affected discharge to rehabilitation (Figure). Patients who were undergoing open plating of a femoral neck fracture or intramedullary nailing of an intertrochanteric, peritrochanteric, or subtrochanteric femoral fracture constituted 30% of all patients discharged to rehabilitation centers. In contrast, patients undergoing percutaneous skeletal fixation of a proximal femoral fracture constituted only 5.5% of all patients discharged to rehabilitation. Based on surgery type, we broke down discharge location further, into categories of skilled nursing facility, unskilled facility (not patient’s previous home), separate acute-care facility, dedicated rehabilitation center, and home. Of all 4815 patients combined, 2102 (43.6%) were discharged to a skilled nursing facility, 31 (0.6%) to an unskilled facility (not home), 106 (2.2%) to separate acute care, 1312 (27.2%) to a dedicated rehabilitation center, and 950 (19.7%) home.
Table 2 lists the significant results from the multivariate logistical analysis comparing discharge to a rehabilitation center and discharge home after controlling for the significant risk factors (Table 1). Current diabetes, history of dyspnea, previous myocardial infarction, history of ischemic attacks, current bleeding disorder, transfusion during hospitalization, previous percutaneous cardiac stenting, chemotherapy, past cerebrovascular accident, presence of cancer, surgery type based on CPT code, history of chronic obstructive pulmonary disease or congestive heart failure, current smoking status, and operative time longer than 90 minutes were not significantly correlated with discharge to rehabilitation in the multivariate analysis. All significant factors were associated with higher odds of discharge to rehabilitation except for DNR status. DNR patients were 2.04 times more likely (95% CI, 1.49-2.78; P < .001) to be discharged home than to rehabilitation centers.
Applying these adjusted odds ratios, we see that an elderly woman (age, >65 years) who underwent general anesthesia with an ASA class higher than 2 was 17.63 times more likely than a patient without these risk factors to be discharged to rehabilitation. If this patient were also dialysis-dependent, she would be 61.52 times more likely than a similar patient without dialysis needs to be discharged to rehabilitation.
Even when controlling for all significant and nonsignificant variables in multivariate logistical analysis, age over 65 years (β = 1.05; P < .001), female sex (β = 1.76; P = .004), dialysis dependence (β = 12.98; P = .036), hypertension requiring medication (β = 1.53; P = .032), and ASA class higher than 2 (β = 1.98; P = .001) were found to be significant risk factors for discharge to rehabilitation.
Discussion
This study was the first to investigate the issue of which patient risk factors allow the practicing orthopedist to identify patients who require rehabilitation after hip fracture surgery. Through our multivariate analysis, which controlled for demographics, comorbidities, and operative factors, we found that older age, female sex, history of percutaneous coronary intervention, dialysis dependence, general anesthesia, and ASA class higher than 2 significantly increased the odds of discharge to a rehabilitation center versus home.
Using our study’s results, we can create a risk stratification model for patients and thereby a means of targeting patients who need rehabilitation and starting the process of finding a rehabilitation bed early in the postoperative course. Our study’s variables are easily measured metrics that may be collected in any hospital setting. Especially for hip fracture patients, early planning and discharge to the appropriate rehabilitation center are important in decreasing LOS and associated hospitalization costs. According to one report,3 about 85% of all hip fracture costs are directly related to LOS, given the unnecessarily long rehabilitation periods in hospitals. Hollingworth and colleagues2 compared costs for patients who remained in the hospital with costs for those discharged with rehabilitation services. Overall costs were significantly lower for patients discharged home with rehabilitation. The authors concluded that 40% of hip fracture patients may be suitable for early discharge.2 In an analysis of Medicare payments for hip fracture treatment, hospital costs including LOS accounted for 60% of all payments.12 The results of these 2 studies suggest that the overall driver of hip fracture costs is prolonged LOS and that, if patients are discharged to rehabilitation, then overall costs may be lowered through a direct reduction in hospital LOS. Given that hip fractures account for almost 350,000 hospital admissions in the United States each year, and using our institution’s average hospital charge per day ($4500), about $1.6 billion may be saved if each patient’s LOS decreased by 1 day.13 Although multiple factors affect LOS, discharge planning is under orthopedists’ direct control. Therefore, early identification of patients who will require rehabilitation may help reduce LOS-associated costs in our health care system.
