Trends in short-term and delayed unplanned readmission in patients with adult spinal deformity undergoing posterior spinal fusion

OBJECTIVE Adult spinal deformity (ASD) affects many people in the US, often causing significant back pain and disability and disrupting activities of daily living. As a result, surgical intervention for deformity correction can help improve quality of life. Unplanned readmissions after surgery can significantly impact patients and the value of care. The aim of this study was to assess the trends in short-term and delayed unplanned readmissions following treatment for ASD. METHODS A retrospective cohort study was performed using the 2016-2019 Nationwide Readmissions Database. All adult patients undergoing thoracic/thoracolumbar posterior spinal fusion (PSF) for ASD were identified using International Classification of Diseases, 10th Revision coding. Patients were stratified into 7-day readmission (7-R), 30-day readmission (30-R), 90-day readmission (90-R), and no readmission (NonR) cohorts. Patient demographics, comorbidities, adverse events (AEs), and clinical outcomes were assessed. RESULTS Of the 3628 ASD patients identified, 550 (15.2%) experienced unplanned readmission (7-R: 131 [3.6%], 30-R: 252 [6.9%], 90-R: 167 [4.6%], NonR: 3078 [84.8%]). Patients in the readmission cohorts had higher rates of Medicare coverage, while the NonR cohort had the highest proportion of private insurance (p = 0.004). The 30-R cohort had the highest frailty score, followed by the 90-R, 7-R, and NonR cohorts (p < 0.001), respectively. The 7-R and 30-R cohorts had the highest prevalence of hypertension (p = 0.002), complicated diabetes (p = 0.002), and chronic pulmonary disease (p = 0.011). In addition, the 7-R and 30-R cohorts had a higher frequency of three or more comorbidities (p = 0.002) and two or more AEs (p < 0.001). On initial admission, the 7-R cohort had the longest mean length of stay (LOS) (p < 0.001), while the 30-R cohort had the greatest rate of nonroutine discharge (p < 0.001) and the highest mean cost of index admission (p = 0.039). On readmission, the 7-R cohort experienced the longest mean LOS (p < 0.001) and highest rate of nonroutine discharge (p = 0.025), with no significant differences in costs between cohorts. CONCLUSIONS Our study suggests that increased comorbidities, AEs, LOS, nonroutine discharge, and hospital expenditures are associated with short-term (7 and 30 days) unplanned readmissions following PSF for ASD patients. Future studies should further investigate these observed trends and work to optimize patient care while minimizing unplanned readmissions and healthcare expenditures.