Introduction: Surgery is generally considered for patients with metastatic epidural spinal cord compression (MESCC) with an estimated life expectancy >3 months. The moderately high risk of bias due to shortfalls in the methodology and reporting of derivation and validation studies might explain why none of the existing clinical prediction models (CPMs) of survival is consistently used. This study aims to develop the first CPMs of survival and quality of life (QoL) based on a large sample of high-quality prospective data from surgical patients with MESCC conducted in accordance to the TRIPOD guidelines.
Methods: Analyses were conducted on 10 imputations of the data from 258 patients from the AOSpine North America study and the Nottingham registry. Using Cox regression, we developed a 1-year CPM of survival with the site of the primary tumor, presence of organ metastasis and SF-36 physical component score as predictors. Using logistic regression, we created CPMs of improvement in QoL at 6 weeks, 3, 6 and 12 months postoperatively; a difference in EQ-5D scores = 0.06 was the outcome measure. Collinearity, interactions and assumptions were assessed. Internal validation was performed using 200 bootstrap iterations. Calibration and discrimination were evaluated.
Results: Although the predictive ability of our 1-year CPM for survival lack robustness, predicting the improvement in QoL at 3 and 12 months postoperatively, using preoperative EQ-5D score as predictor, showed adequate calibration and the optimism-corrected discrimination was 0.79 (95% CI: 0.74-0.84) and 0.73 (95% CI: 0.67-0.80), respectively.
Conclusions: We have created and internally validated the first CPMs of QoL at 3 and 12 months after surgery in patients with MESCC. These CPMs consist of the preoperative EQ-5D score which is easily obtainable in the preoperative period. The predictive performance of all current CPMs of survival and QoL for patients with MESCC should undergo full externally validation to assess their relative generalizability.
Patient Care: a better insight in the likelihood to achieve improvement in QoL at 3 and 12 months postoperatively provide valuable information in the therapeutic decision-making process and help patients form more realistic expectations.
Learning Objectives: Present the development and internal validation of the first clinical prediction models of quality of life at 3 and 12 months after surgery in patients with metastatic epidural spinal cord compression