Assessing social disparities in inpatient vs. outpatient arthroplasty: a in-state database analysis

Given the growing emphasis on patient outcomes, including postoperative complications, in total joint arthroplasty (TJA), investigating the rise of outpatient arthroplasty is warranted. Concerns exist over the safety of discharging patients home on the same day due to increased readmission and complication rates. However, psychological benefits and lower costs provide an incentive for outpatient arthroplasty. The influence of social determinants of health disparities on outpatient arthroplasty remains unexplored. One metric that assesses social disparities, including the following individual components: socioeconomic status, household composition, minority status, and housing and transportation, is the Social Vulnerability Index (SVI). As such, we aimed to compare: (1) mean overall SVI and mean SVI for each component and (2) risk factors for total complications between patients undergoing inpatient and outpatient arthroplasty.

Patients who underwent TJA between January 1, 2022 and December 31, 2022 were identified. Data were drawn from the Maryland State Inpatient Database (SID). A total of 7817 patients had TJA within this time period. Patients were divided into inpatient arthroplasty (n = 1429) and outpatient arthroplasty (n = 6338). The mean SVI was compared between inpatient and outpatient procedures for each themed score. The SVI identifies communities that may need support cause by external stresses on human health based on four themed scores: socioeconomic status; household composition and disability; minority status and language; and housing and transportation. The SVI uses the United States Census data to rank census tracts for each individual theme, as well as an overall social vulnerability score. The higher the SVI, the more social vulnerability, or resources needed to thrive in that area. Multivariate logistic regression analyses were performed to identify independent risk factors for total complications following TJA after controlling for risk factors and patient comorbidities. Total complications included: infection, aseptic loosening, dislocation, arthrofibrosis, mechanical complication, pain, and periprosthetic fracture.

Patients who had inpatient arthroplasty had higher overall SVI scores (0.45 vs. 0.42, P < 0.001). The SVI scores were higher for patients who had inpatient arthroplasty for socioeconomic status (0.36 vs. 0.32, P < 0.001), minority status and language (0.76 vs. 0.74, P < 0.001), and housing and transportation (0.53 vs. 0.50, P < 0.001) compared to outpatient arthroplasty, respectively. There was no difference between inpatient and outpatient arthroplasty for household composition and disability (0.41 vs. 0.41, P = 0.99). When controlling for comorbidities, inpatient arthroplasty [Odds Ratio (OR) 1.91, 95% Confidence Interval (CI) 1.23-2.95, P = 0.004], hypertension (OR 2.11, 95% CI 1.23-3.62, P = 0.007), and housing and transportation (OR 2.00, 95% CI 1.17-3.42, P = 0.012) were independent risk factors for total complications.

Inpatient arthroplasty was associated with increased social disparities across several components of deprivation as well as an independent risk factor total complications following TJA. To the best of our knowledge, this study is the first to examine the negative repercussions of inpatient arthroplasty through the lens of social disparities and can target specific areas for intervention.