Analysis of Short-Term versus Long-Term Readmission-Free Survival After Metastatic Spine Tumor Surgery

BACKGROUND: Readmission-free survival (ReAFS) is a novel clinical and quality metric after metastatic spine tumor surgery (MSTS). We believe that factors influencing ReAFS after index MSTS vary based on time. We considered 2 time frames and defined short-term ReAFS as survival without an unplanned hospital readmission up to 90 days and long-term ReAFS as survival without unplanned hospital readmission up to 1 year after MSTS. METHODS: We retrospectively analyzed 266 patients who underwent MSTS between 2005 and 2016. All relevant oncologic, surgical and follow-up data were collected. Multivariate logistic regression analysis was used to analyze prognostic factors associated with higher probability of short-term ReAFS and long-term ReAFS. RESULTS: Multivariate analysis showed that Eastern Cooperative Oncology Group score <= 2 (P = 0.011), preoperative hemoglobin (Hb) level >12 g/dL (P = 0.008), <= 3 comorbidities (P = 0.052), shorter index length of stay <= 10 days (P = 0.007), and absence of neurologic/hematologic complications during index stay (P = 0.015) significantly increased the probability of short-term ReAFS, whereas preoperative lib level >12 g/dL (P = 0.003) or tumor primaries with advanced treatment modalities such as breast (P 0.012), hematologic (P = 0.006), prostate (P = 004 and renal/thyroid (P = 0.038) as opposed to aggressive lung tumor primaries were associated with significantly higher probability of long-term ReAFS. CONCLUSIONS: Patient and treatment factors predominantly influence ReAFS up to 90 days, whereas primary tumor-related factors alongside general health influence ReAFS beyond 90 days after index MSTS. Awareness of these factors may help oncologists and surgeons optimize treatment planning. The clinical significance of this study will continue to evolve, because we have been witnessing over the past decade that patients are becoming more involved in both their general health and understanding the natural history of the diseases that affect them.