Comparison study of patient demographics, causes, and risk factors associated with 90-day readmissions following primary reverse shoulder arthroplasty

Background

The use of reverse total shoulder arthroplasty (rTSA) has risen exponentially, likely due to the consistently favorable outcomes, an aging population, and expanding surgical indications. This increase in operative volume has led to a proportional increase inhospital readmissions. The purpose of this study was to (1) determine the 90-day readmission rates following rTSA, (2) identify the common surgical causes for readmission, and (3) evaluate patient-related risk factors associated with increased risk of readmission.

Methods

Patients undergoing rTSA were identified using a nationwide administrative database. The study group cohort included those patients who were readmitted within 90 days following the index procedure; whereas patients not readmitted served as controls. The query yielded 116,893 patients with 4705 readmitted and 112,118 not readmitted. Demographic information including sex, age, comorbidities, and Elixhauser Comorbidity index (ECI) were compared between groups. Chi-square analyses were used to compare patient demographics. Multivariate binomial logistics regression analyses were used to calculate odds ratios (ORs) on patient-related risk factors for 90-day readmissions. A P value less than .007 was considered statistically significant based on Bonferroni correction.

Results

The overall readmission rate was 4.03%, 40.5% of which were orthopedic-related. The most common causes of readmission were prosthetic dislocation (0.97%), deep and superficial surgical site infection (0.34%), and postoperative pain (0.19%). Readmitted patients had significantly higher rates of comorbid conditions. Comorbid conditions with the highest association with 90-day readmission were body mass index > 40 (OR = 2.39), rheumatoid arthritis (OR = 1.90), iron deficiency anemia (OR = 1.79), and chronic kidney disease (OR = 1.62). ECI was significantly higher among the readmitted group (8.8 vs. 6.2; P < .001).

Conclusion

Patients undergoing rTSA with increased body mass index, rheumatoid artthritis, chronic kidney disease and iron deficiency anemia were at increased risk for readmission. Patients with increased ECI also had increased odds of readmission. Well-powered prospective studies are necessary to better understand the impact of comorbid conditions on the risk for readmission. However, the current study can be used by orthopedic surgeons and other health-care professionals to educate patients with significant comorbid conditions to better predict the chance of readmission after rTSA.