Smoking and Total Hip Arthroplasty in 2014: Increased Inpatient Complications and Costs

Background: Smoking 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 the inpatient complications and inpatient costs on a national level of smokers undergoing THA.

Methods: The Nationwide Inpatient Sample (NIS) was used to identify all primary elective THAs performed in the United States in 2014. This cohort was further stratified by smoking status based on ICD9 305.1, ‘tobacco use disorder’. Inpatient hospital characteristics and complications rates were assessed using univariable and multivariable models.

Results: The NIS had 63,446 admissions recorded for primary THAs in 2014, corresponding to an estimated 317,230 cases nationwide for that year. The smoking rate in the NIS population was 20.7% (13,108 cases). Smokers were slightly yet significantly younger than nonsmokers (63.5 years versus 64.8 years). The smoking group had a significantly longer hospital stay (3.0 days vs 2.5 days) and higher total hospital costs ($17,012 vs $15,742). After using a multi-variable logistic model adjusting for age, gender and comorbidities, smokers were found to have a significantly higher odds ratio (OR(95%CI)) for the following complications: myocardial infarction 12.5(3.7-42.5), cardiac arrest 7.58(1.8-32.8), pneumonia 5.0(2.7-9.5), sepsis 12.8(3.6-45.4), acute renal failure 2.9(2.2-3.6), urinary tract infection 2.0(1.5-2.8), transfusion 1.2(1.0-1.3) and discharge to skilled nursing facility 1.5(1.3-1.6). Notably, inpatient mortality was not significantly higher in smoking patients, although this complication was exceedingly rare (0.05%) in this NIS population.

Conclusions: Smoking remains a highly prevalent risk factor in THA patients in the United States. Smoking patients have a significantly higher rate of complications without increased odds of inpatient mortality and incur significantly higher early postoperative inpatient costs. These findings are important for risk stratification, bundled-payment considerations, as well as perioperative patient education and intervention.