Assessing frailty screening tools for predicting morbidity for suboccipital decompression in adults with Chiari malformation type I.

Objective: The revised Risk Analysis Index (RAI-rev) and modified 5-item frailty index (mFI-5) are comprehensive assessment tools of frailty that have been used to predict neurosurgical outcomes. The aim of this study was to investigate the utility of these tools to predict extended hospital length of stay (LOS), nonroutine discharge (NRD), and 30-day adverse events (AEs) among patients with Chiari malformation type I (CM-I) undergoing suboccipital decompression.

Methods: The authors conducted a retrospective cohort study using the 2011-2022 American College of Surgeons National Surgical Quality Improvement Program database to identify adults with CM-I who underwent suboccipital decompression. Using receiver operating characteristic (ROC) curve and multivariable analyses, we compared the discriminative thresholds and independent associations of RAI-rev, mFI-5, and patient age, with extended LOS, NRD, and 30-day AEs.

Results: Among 1225 patients studied, 806 patients (65.8%) were categorized as robust, 388 (31.7%) as typical and 31 (2.5%) as frail using RAI-rev, whereas 946 (77.2%) were categorized as robust, 222 (18.1%) as typical, and 57 (4.7%) as frail according to mFI-5. Multivariable analysis revealed RAI-rev (adjusted odds ratio [aOR] 4.37, 95% CI 1.40-13.70) and mFI-5 (aOR 2.71, 95% CI 1.38-5.32) scores as significant predictors of extended LOS for frail patients. RAI-rev was also a significant predictor of NRD for patients in the typical (aOR 2.57, 95% CI 1.00-6.60) and frail (aOR 15.70, 95% CI 3.27-75.44) groups. Neither the RAI-rev nor mFI-5 score significantly predicted 30-day AEs. On ROC analysis, there were no significant differences between the RAI-rev score (area under the curve [AUC] 0.5608), mFI-5 score (AUC 0.5626), and age (AUC 0.5496) in predicting LOS. Similarly, no differences were observed between the RAI-rev score, mFI-5 score, and age in predicting 30-day AEs. Notably, the RAI-rev score (AUC 0.7234) exhibited superior performance in predicting NRD compared with the mFI-5 score (p = 0.038) and age (p = 0.016).

Conclusions: The authors' findings demonstrate that while both RAI-rev- and mFI-5-defined frailty were significantly associated with extended LOS and NRD, RAI-rev outperformed mFI-5 in predicting NRD.