Article Text

Original research
Higher Hospital Frailty Risk Score is associated with increased complications and healthcare resource utilization after endovascular treatment of ruptured intracranial aneurysms
Free
1. Andrew B Koo1,
3. Daniela Renedo1,
4. Margot Sarkozy1,
5. Josiah Sherman1,
6. Benjamin C Reeves1,
7. John Havlik1,
8. Joseph Antonios1,
9. Nanthiya Sujijantarat1,
10. Ryan Hebert1,
11. Ajay Malhotra2,
12. Charles Matouk1
1. 1 Department of Neurosurgery, Yale University School of Medicine, New Haven, Connecticut, USA
2. 2 Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, Connecticut, USA
1. Correspondence to Dr Charles Matouk, Neurosurgery, Yale University School of Medicine, New Haven, Connecticut, USA; charles.matouk{at}yale.edu

## Abstract

Aim To use the Hospital Frailty Risk Score (HFRS) to investigate the impact of frailty on complication rates and healthcare resource utilization in patients who underwent endovascular treatment of ruptured intracranial aneurysms (IAs).

Methods A retrospective cohort study was performed using the 2016–2019 National Inpatient Sample database. All adult patients (≥18 years) undergoing endovascular treatment for IAs after subarachnoid hemorrhage were identified using ICD-10-CM codes. Patients were categorized into frailty cohorts: low (HFRS <5), intermediate (HFRS 5–15) and high (HFRS >15). Patient demographics, adverse events, length of stay (LOS), discharge disposition, and total cost of admission were assessed. Multivariate logistic regression analysis was used to identify independent predictors of prolonged LOS, increased cost, and non-routine discharge.

Table 3

### Logistic multivariate regression analyses

Increasing frailty was significantly associated with greater odds of experiencing a prolonged LOS (intermediate: OR 2.38 (95% CI 1.84 to 3.09), p<0.001; high: OR 4.49 (95% CI 3.36 to 6.00), p<0.001) (table 4). Similarly, increasing frailty was significantly associated with an increased cost of hospital admission (intermediate: OR 2.15 (95% CI 1.66 to 2.77), p<0.001; high: OR 3.62 (95% CI 2.71 to 4.83), p<0.001) (table 4). Finally, the odds of experiencing a non-routine discharge were found to increase with advancing HFRS (intermediate: OR 2.13 (95% CI 1.79 to 2.55), p<0.001; high: OR 4.17 (95% CI 3.26 to 5.33), p<0.001) (table 4). The complete univariate and multivariate data are available in online supplemental tables 3–5.

Table 4

Logistic multivariate regression analyses on prolonged LOS, increased cost, and non-routine discharge disposition

## Discussion

This retrospective national database study of 33 840 patients who underwent endovascular treatment of a ruptured IA shows that increasing frailty (as measured by HFRS) was associated with increased LOS, rates of hospital AEs, rates of non-routine discharges, and total costs. Further, on multivariate analysis, we found that intermediate and high frailty independently predicted prolonged LOS, increased cost, and non-routine discharge.

Frailty is increasingly recognized as a predisposing factor for adverse health outcomes and increased healthcare resource utilization.26 27 Preliminary efforts have begun to assess the impact of frailty on patients with aneurysmal SAH. In a retrospective analysis of 217 patients who underwent surgical clipping of ruptured IAs, McIntyre et al found that ~26% of patients were frail, defined as mFI score ≥2.11 Similarly, in a single-institution study of 173 elderly patients (≥60 years) who underwent surgical clipping of a ruptured IA, Yue et al found frailty, as defined by the presence of severe anemia, hypoalbuminemia, or low body mass index, to be common affecting ~45% of their patient cohort.14 In our study, nearly 75% of patients undergoing endovascular treatment for a ruptured IA were considered to have intermediate (59.3%) or high (17.2%) frailty, as defined by the HFRS.

While there is a paucity of studies directly assessing frailty and outcomes, prior studies have attempted to identify the relationship between frailty and complications after management of ruptured IAs. In the retrospective study of 217 patients with aSAH by McIntyre et al, the authors found on multivariate regression analysis that frail patients were significantly more likely to experience a complication during their hospital stay (OR 2.6).11 In a retrospective NIS database study of 5353 patients undergoing treatment for ruptured aneurysms between 2012 and 2015, Chotai et al found on multivariate analysis that the odds of experiencing any inpatient complication significantly increased as the neurovascular comorbidity index (NCI) score, a value closely related to frailty, progressed from 1 (OR 1.13) to 4 (OR 1.58) and to 7 (OR 2.05).28 Similarly, our study of patients undergoing endovascular treatment of ruptured IAs found that, as the severity of frailty increased, the rate of perioperative AEs increased by more than fivefold from the low to the high frailty cohort. Further studies assessing frailty in ruptured IAs are needed to aid in patient risk stratification and patient-centered management strategies.

While there is a paucity of studies directly assessing the impact of frailty with hospital LOS and non-routine discharges in patients with ruptured IA, there have been a few that evaluated the impact of comorbidities and other factors closely associated with frailty. In a retrospective NIS database study of 19 034 patients who underwent clipping or coiling of a ruptured or unruptured IA between 2002 and 2006, Hoh et al demonstrated that older age as well as diabetes, coagulopathy, CHF, renal failure, peripheral vascular disorders, and neurological or electrolyte disorders were each independently associated with longer hospitalizations.29 Of these identified comorbidities, four are included in the commonly used 11-item mFI,30 three are included in the 5-item mFI,31 and five are included in the HFRS.17

However, not all studies have reported results similar to the findings outlined above. For example, in a retrospective observational database study of 203 patients treated for a ruptured IA between 2012 and 2017, Hammer et al found that all analyzed comorbidities including hypertension, diabetes, hypothyroidism, cholesterinemia, and smoking did not have a significant impact on LOS in the intensive care unit.32 Analogous to the aforementioned studies, our study found that mean hospital LOS more than doubled when comparing low to high HFRS cohorts. Furthermore, on multivariate analysis, we also found that both intermediate and high frailty were significant independent predictors of prolonged LOS when compared with patients with low baseline frailty. With respect to discharge disposition, in the study by McIntyre et al the authors showed on multivariate analysis that frail patients were significantly less likely to be discharged to home (OR 0.32).11 Our study also found that rates of non-routine discharge were nearly four times higher in patients with high frailty than in those with low frailty. As prolonged LOS and non-routine discharges have repeatedly been shown to increase healthcare resource utilization and be associated with inferior outcomes in patients undergoing various neurosurgical procedures, further studies should be done to better define the relationship between frailty and LOS following treatment of ruptured IAs.

While few studies have examined the impact of frailty on the cost of hospital admission in patients undergoing treatment for IAs, there have been efforts to characterize the effect of frailty-associated factors on hospital admission cost within this patient population. In the NIS database study of patients treated for a ruptured IA by Chotai et al, the authors found on regression analysis that higher NCI scores were associated with a greater cost of hospital admission.28 Consistent with these findings, the NIS database study of patients with ruptured or unruptured IA by Hoh et al demonstrated that frailty-associated comorbidities (eg, diabetes, CHF, coagulopathy, electrolyte disorders, neurological disorders, renal failure, and peripheral vascular disorders) and older age were each independently associated with greater hospital costs.29 Similarly, our study found that the mean cost of hospital admission more than doubled between the low frailty and the high frailty cohort. These data, although limited, demonstrate how frailty may be contributing to the soaring healthcare costs in the USA.

This study has a number of limitations inherent to all administrative databases, including the NIS. First, the analysis is retrospective, potentially limiting the interpretation of our results. The data are also available only by ICD-10-CM codes, which may contain coding and reporting biases. Second, data may be misclassified or incomplete. Third, information regarding preoperative factors such as the size of the IA prior to rupture is unavailable, which may have an unrecognized effect on our results. Also, there may be additional confounding variables present which are unavailable or have not been measured. Finally, given the NIS has information specific to a single inpatient admission, we cannot comment on long-term functional outcomes or the durability of treatment. Despite these limitations, this study uses one of the largest inpatient databases in the USA to provide unique insights into the impact of frailty on postoperative outcomes and healthcare resource utilization for patients undergoing endovascular treatment of ruptured IAs.

## Conclusion

Our study is the first to use the HFRS to assess the impact of frailty on patients who underwent endovascular treatment for ruptured IAs. We found that greater frailty was associated with increased complications, prolonged hospital LOS, higher total costs, and non-routine discharge. These results highlight the need for further studies that examine the impact of frailty on outcomes following endovascular treatment for a ruptured IA, as it may improve patient care and reduce healthcare resource utilization.

## Data availability statement

All data relevant to the study are included in the article or uploaded as supplemental information. Not applicable.

• ## Supplementary Data

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