BackgroundSmoking is a potentially modifiable risk factor that may impact the overall outcomes of total hip arthroplasty (THA). In an era of bundled payments for THA, the purpose of this study was to evaluate, on a national level, the inpatient complications and additional costs of smokers undergoing THA. MethodsThe Nationwide Inpatient Sample was used to identify all primary elective THAs performed in the United States in 2014. This cohort was further stratified by smoking status. Inpatient hospital characteristics, costs, and complications rates were assessed. ResultsThe Nationwide Inpatient Sample had 63,446 admissions recorded for primary THAs in 2014, corresponding to an estimated 317,230 cases nationwide. The smoking rate was 20.7%. Smokers were slightly yet significantly younger than nonsmokers (63.5 years vs 64.8 years; P < .0001). The smoking group had a significantly longer hospital stay and higher total hospital costs (both P < .0001). After using a multivariable logistic model adjusting for age, gender, and comorbidities, smokers were found to have a significantly higher odds ratio (OR [95% confidence interval {CI}]) for myocardial infarction (15.5 [5.0-47.5]), cardiac arrest (10.1 [2.2-47.6]), pneumonia (4.7 [2.4-9.1]), urinary tract infection (1.9 [1.4-2.7]), sepsis (13.1 [3.5-49.0]), acute renal failure (2.9 [2.2-3.7]), discharge to a skilled nursing facility (1.3 [1.2-1.4]), and mortality (11.7 [2.0-70.5]). ConclusionsSmoking remains a highly prevalent and important risk factor for complications in elective primary THA in the United States. Patients who smoke have a significantly higher rate of complications and generate significantly higher postoperative inpatient costs. These findings are important for risk stratification, bundled payment considerations, as well as perioperative patient education and intervention.