A comparison of frailty indices in predicting length of inpatient stay and discharge destination following angiogram-negative subarachnoid hemorrhage

Abstract

Background and purpose: While patients with angiogram-negative subarachnoid hemorrhages (ANSAH) have better prognoses than those with aneurysmal SAH, frailty's impact on outcomes in ANSAH is unclear. We previously showed that the modified frailty index (mFI-11) is associated with poor outcomes following ANSAH. Here, we compared the mFI-5, mFI-11, Charlson Comorbidity Index (CCI), and temporalis thickness (TMT) to determine which index was the best predictor of ANSAH outcomes and mortality rates.

Methods: In this retrospective cohort analysis between 2014 and 2018, patients with non-traumatic, angiogram negative SAH (ANSAH) were identified. The admission mFI-5, mFI-11, CCI, and TMT were calculated for each patient. Primary outcomes were mortality rate, discharge location, and prolonged length of stay (PLOS; LOS >85^th percentile). Multivariate logistic regression and receiver operating characteristic (ROC) curves were used to evaluate frailty as predictors of primary endpoints.

Results: We included 75 patients with a mean age of 55.4 ± 1.5 years. There were 4 patient deaths (5.3%), 53 patients (70.7%) discharged home, and 11 patients (14.7%) with PLOS. On ROC analysis, the mFI-5 had the highest discriminatory value for mortality (AUC = 0.97) while the mFI-11 was most discriminatory for discharge home (AUC = 0.85) and PLOS (AUC = 0.78). On multivariate analysis, the only independent predictor of mortality was the mFI-11 (OR = 0.46; 95%CI: 1.45-14.23; p = 0.009) while the mFI-5 was the best predictor of discharge home (OR = 0.21; 95% CI: 0.08-0.61; p = 0.004). On multivariate analysis, the only independent predictor of PLOS was the Hunt and Hess score (OR = 2.63; 95%CI: 1.38-5.00; p = 0.003). The CCI and TMT were inferior to either mFI for predicting primary endpoints.

Conclusions: Increasing frailty is associated with poorer outcomes and higher mortality following ANSAH. The mFI-5 and mFI-11 were found to be superior predictors of discharge home and mortality rate. While larger prospective study is needed, frailty, as measured by mFI-11 and -5, should be considered when evaluating ANSAH prognosis.

Keywords: Charlson Comorbidity index; Subarachnoid hemorrhage; angiogram-negative subarachnoid hemorrhage; modified frailty index; temporalis thickness.