What are the incidence and risk factors of in-hospital mortality after venous thromboembolism events in total hip and knee arthroplasty patients?

BACKGROUND: Pulmonary embolism and deep vein thrombosis, together referred to as venous thromboembolism (VTE), are serious and potentially preventable complications after total hip arthroplasty and total knee arthroplasty. The aim of this study was to investigate the incidence of mortality after VTE events and assess the risk factors that are associated with it. METHODS: The Nationwide Inpatient Sample was used to estimate the total number of total hip arthroplasty, total knee arthroplasty, VTE events, and mortality using the International Classification of Diseases, Ninth Revision procedure codes from 2003 to 2012. Patients' demographics, Elixhauser, and Charlson comorbidity indices were used to identify the risk factors associated with in-hospital VTEs and mortality. RESULTS: A total of 1,805,621 THAs and TKAs were included. The overall rate of VTE was 0.93%. The in-hospital mortality rate among patients with VTEs was 7.1% vs 0.30% in patients without VTEs (P-value < .0001). The risk factors for mortality after VTE events in descending order were as follows: hypercoagulable state (odds ratio [OR]: 5.3, 95% confidence interval [CI]: 3.6-5.8), metastatic cancer (OR: 5.2, 95% CI: 3.3-5.6), myocardial infarction (OR: 4.2, 95% CI: 2.3-4.7), peripheral vascular disease (OR: 3.6, 95% CI: 3.2-4.0), cardiac arrhythmias (OR: 3.2, 95% CI: 1.6-4.3), advanced age (OR: 3.1, 95% CI: 2.3-3.7), electrolyte disorders (OR: 3.1, 95% CI: 2.2-3.6), pulmonary circulation disorders (OR: 2.9, 95% CI: 2.6-3.3), depression (OR: 2.8, 95% CI: 1.6-3.4), complicated diabetes (OR: 2.7, 95% CI: 2.1-3.2), weight loss (OR: 2.6, 95% CI: 2.2-3.3), renal failure (OR: 2.6, 95% CI: 1.7-3.5), chronic pulmonary disease (OR: 2.5, 95% CI: 1.3-3.1), valvular disease (OR: 2.4, 95% CI: 1.8-2.7), liver disease (OR: 1.7, 95% CI: 1.2-1.9), and obesity (OR: 1.6, 95% CI: 1.5-1.9). CONCLUSIONS: In-hospital VTE has a significant in-hospital mortality rate. Several of the identified risk factors in this study are modifiable preoperatively. We strongly urge the orthopaedic community to be cognizant of these risk factors and emphasize on optimizing patients' comorbidities before an elective arthroplasty.