Nationwide Patterns of Pathologic Fractures Among Patients Hospitalized with Bone Metastases

Abstract

Bone metastases can significantly affect quality-of-life, especially if they lead to pathologic fractures. However, it is unclear which patients are more likely to develop pathologic fractures when they have bone metastases. We aim to determine risk factors for pathologic fracture among those who are admitted with bone metastases and to evaluate the association of pathologic fracture with clinical and economic outcomes. The Healthcare Cost and Utilization Project Nationwide Inpatient Sample (HCUP-NIS) was queried for all patients hospitalized with bone metastases and pathologic fractures in 2016. Baseline differences in demographic, clinical, socioeconomic, and hospital-related characteristics between patients with and without fractures were assessed by chi-square and ANOVA testing. Multivariable logistic regression was used to identify factors associated with fractures. Weighted frequencies were used to create national estimates for all data analysis. In 2016, 272,275 hospital admissions were associated with a diagnosis of bone metastases, of which 11.1% were found to have a pathologic fracture. Patients with fractures have a longer length-of-hospital-stay (mean 8.2 vs 6.3 days, p<0.001), and higher cost-of-hospital-stay (mean $23,526 vs $15,377, p<0.001) compared to patients without pathologic fractures. On multivariable analysis, primary cancers associated with increased risk of pathologic facture included multiple myeloma (odds ratio [OR] 2.91; 95% CI = 2.40-3.53), liver & intrahepatic bile duct (OR 1.72; 95% CI = 1.37-2.16), and kidney and renal pelvis cancer (OR 1.39; 95% CI = 1.21-1.60). Comorbidities significantly associated with fracture included osteoporosis (OR 1.68; 95% CI = 1.44-1.96), paralysis (OR 1.35; 95% CI = 1.18-1.55), and drug (OR 1.35; 95% CI = 1.09-1.66) and alcohol abuse (OR 1.33; 95% CI = 1.07-1.65). Approximately 11% of hospitalized patients with bone metastases presented with a concomitant pathologic fracture, which was associated with longer inpatient stay and higher cost. Multiple myeloma and osteoporosis were associated with higher risk of pathologic fracture. These groups may benefit from increased outpatient monitoring, prophylactic stabilization, or early irradiation.