Hospital and patient factors predict length of stay in patients with osteoarthritis undergoing total primary hip replacement.

OBJECTIVES

Over 450,000 primary total hip arthroplasties (THA) are performed each year in the US, with osteoarthritis (OA) as the major indication for primary THA. We examined the association of patient, payer, hospital, and geographic factors with extended lengths of stay (eLOS) and increased hospital costs in primary THA.

METHODS

We utilized the National Inpatient Sample (NIS) to identify patients with OA who underwent primary THA in 2019. Diagnoses and procedures were identified using the International Classification of Disease (ICD-10) codes. We stratified healthcare/resource utilization by the occurrence of an extended length of hospital stay (eLOS) at 90th percentile or higher, i.e.,>3days. We used univariate and multivariable-adjusted logistic regression analyses to assess whether patient, payer, hospital, and geographic factors associated with an eLOS. Predictive probabilities from multivariable analyses were used in area under the curve (AUC) analysis.

RESULTS

There were 1,525,730 primary THAs performed for patients with OA during 2016-2019. Patient race and ethnicity, Medicaid or Medicare payer status, income, age/sex and nearly all regional, and hospital, characteristics were independently associated with eLOS (>3days; ROC C-statistic=0.78).

CONCLUSION

Patient race and ethnicity and insurance payer status are important patient-level determinants of longer LOS for primary THA hospitalizations in the US. Well-known geographical and hospital-level factors are negatively associated with the hospitalization stay duration outcomes of primary THA in patients with OA. Policy and other interventions targeting these factors may help reduce inpatient healthcare utilization for primary THA.