In this retrospective national database study of 3,345 adult patients undergoing surgery for spinal meningiomas, we demonstrated that patients with Intermediate-High HFRS had greater LOS, increased rates of non-routine discharge, and increased costs of admission compared to patients with Low HFRS. Moreover, on multivariate analysis, increased HFRS was independently associated with extended LOS, non-routine discharge, and increased costs.
While there is a paucity of studies assessing frailty risk in spinal meningioma patients, several previous studies have assessed the prevalence of frailty risk in patients undergoing surgery for other metastatic and primary spinal tumors. In a retrospective single-institution cohort study of 479 patients undergoing surgery for metastatic spinal tumors from 2010 to 2019, Massaad et al. showed that 93.5% of patients had some degree of MSTFI-defined frailty risk, with 23.2% having mild, 33.8% having moderate, and 36.5% having severe frailty risk.24 Additionally, in a retrospective single-institution cohort study of 322 patients undergoing surgery for spinal metastases from 2013 to 2020, Hersh et al. demonstrated that 72.8% of patients had mFI-5 scores ≥ 1 and that 80.6% had MSTFI scores ≥ 1, corresponding to some degree of frailty risk.27 Similarly, in a retrospective database cohort study of 4,583 patients undergoing surgery for spine metastases from 2002 to 2011, De la Garza Ramos et al. found that 40.1% of patients had mild MSTFI-defined frailty risk (MSTFI = 1), 24.7% of patients had moderate frailty risk (MSTFI = 2), and 18.0% of patients had severe frailty risk (MSTFI ≥ 3).29 The prevalence of increased HFRS in patients undergoing spinal tumor surgeries has also been assessed. In a retrospective NIS database study of 5,955 patients undergoing surgery for primary spinal intradural or cord tumors from 2016 to 2018, Elsamadicy et al. found that 21.2% of patients had intermediate to high frailty risk (HFRS ≥ 5).8 Similarly, in a retrospective NIS database study of 11,480 patients undergoing surgery for metastatic bony spinal tumors from 2016 to 2019, Elsamadicy et al. showed that 61.7% of patients had low frailty risk (HFRS < 5), 36.2% had intermediate frailty risk (HFRS 5–15), and 2.0% had high frailty risk (HFRS > 15).7 Notably, in a meta-analysis of 96 studies assessing verified frailty in patients over the age of 65, Doody et al. found that frailty had an overall prevalence of 22.2% among all patients with primary neoplastic morbidities, 23.2% among female patients with primary neoplastic morbidities, and 32.4% among all patients admitted following surgery.23 Furthermore, the authors noted that across the assessed studies, female patients had a combined frailty prevalence of 51.9% versus 47.0% for males, though the difference was not statistically significant.23 Analogous to the aforementioned studies, our study found that 15.9% of patients had Intermediate-High HFRS-defined frailty risk (HFRS ≥ 5). When further stratified by sex, we found that 15.8% of female patients in our study had Intermediate-High frailty risk versus 16.0% of male patients. Given the increased prevalence of frailty in this patient population in males and females, additional studies are necessary to further refine approaches to assessing frailty.
Several studies have found an association between increased risk of frailty and postoperative complications in patients undergoing surgery for metastatic and primary spinal tumors. In the Hersh et al. study of 322 patients undergoing surgery for spinal metastases, the authors found that higher MSTFI and Charlson Comorbidity Index (CCI) scores were significantly associated with experiencing ≥ 1 postoperative complication.27 Additionally, in the retrospective study of 4,583 patients undergoing surgery for spinal metastases, De la Garza Ramos et al. demonstrated that mild (OR: 1.88), moderate (OR: 3.83), and severe (OR: 6.97) MSTFI-defined frailty risk had significantly greater odds of experiencing a postoperative complication.29 Similarly, in a retrospective study of 1,589 patients undergoing surgery for primary spinal tumors from 2002 to 2011, Ahmed et al. showed that patients with mild, moderate, and severe frailty risk each had significantly greater odds of experiencing postoperative complications.25 Moreover, in the retrospective study of 5,955 patients undergoing surgery for primary spinal or intradural cord tumors, Elsamadicy et al. found that the increased-frailty-risk cohort (HFRS ≥ 5) had a significantly higher rate of postoperative complications.8 Similarly, in the retrospective study of 11,480 patients undergoing surgery for metastatic bony tumors, Elsamadicy et al. showed that the proportion of patients experiencing any postoperative complication increased along with increasing HFRS.7 Similar to these results, our study found that a significantly greater proportion of patients in the Intermediate-High frailty risk cohort had one or more postoperative complications. Unfortunately, a comparison of complication rates between males and females in the Intermediate-High frailty risk group was challenging due to the relatively low number of male patients in this cohort. Though sex is not a modifiable risk factor, a further understanding of risks of complications in male and female patients could lead to more effective preoperative risk stratification, potentially improving patient education and shared decision-making. Overall, these results underscore the need to better elucidate how frailty risk may contribute to complications in these patients. Creating patient specific protocols that incorporates the severity of frailty may be helpful in identifying and caring for higher risk patients.
While there is a paucity of spinal meningioma studies, there have been prior metastatic and primary spinal tumor studies demonstrating associations between elevated frailty risk and increased healthcare resource utilization, such as prolonged hospitalizations and non-routine discharge disposition. In the retrospective study of 4,583 patients undergoing surgery for spinal metastases, De la Garza Ramos et al. found that LOS significantly increased along with increasing MSTFI-defined frailty risk.29 Additionally, in the study of 322 patients undergoing surgery for spinal metastases, Hersh et al. showed that higher mFI-5-defined- and MSTFI-defined frailty risks were each significantly associated with prolonged LOS and non-routine discharges on multivariate analysis.27 Furthermore, in a retrospective Nationwide Readmissions Database (NRD) study of 1,974 patients with increased frailty risk and 1,975 controls undergoing surgery for spinal metastases from 2016 to 2017, Bakhsheshian et al. demonstrated that increased frailty risk was significantly associated with prolonged LOS (OR: 7.54) and non-routine discharge (OR: 3.86) on multivariate analysis.36 Moreover, in a retrospective single-institution study of 350 adult patients undergoing surgery for vertebral column tumors, Ehresman et al. found that higher mFI-5-defined frailty risk was a significant predictor of non-routine discharge.37 Regarding HFRS-defined frailty risk, in the retrospective NIS database study of 11,480 patients undergoing surgery for metastatic spinal column tumors, Elsamadicy et al. showed that intermediate (HFRS 5–15) and high (HFRS > 15) frailty risk each independently predicted extended LOS and non-routine discharge.7 Similarly, in the retrospective NIS database study of 5,955 patients undergoing surgery for primary spinal or intradural cord tumors, Elsamadicy et al. observed that increased HFRS-defined frailty risk was significantly associated with extended LOS and non-routine discharge.8 Analogous to these results, our study found that patients in the Intermediate-High frailty risk cohort had significantly greater mean LOS and rates of non-routine discharge. Additionally, we identified increased HFRS-defined frailty risk as a significant predictor of prolonged LOS in males and females on multivariate analysis; increased HFRS was also found to be significantly associated with non-routine discharge. Further studies on the impact of frailty on prolonged LOS and non-routine discharges are necessary to continue curating Enhanced Recovery After Surgery (ERAS) protocols for these patient populations.
Given the apparent relationship between increased frailty risk and healthcare resource utilization, a few studies have attempted to assess the financial implications associated with increased frailty risk within spine oncology. In the retrospective NRD database study of 1,974 patients with increased risk of frailty and 1,975 low-frailty-risk controls undergoing surgery for spinal metastases from 2016 to 2017, Bakhsheshian et al. observed that patients with greater frailty risk had higher mean costs of admission and that increased risk of frailty was an independent predictor of increased costs.36 Conversely, in the retrospective NIS database study of 11,480 patients undergoing surgery for metastatic spinal column tumors, Elsamadicy et al. found that while mean total costs increased significantly along with increasing HFRS, intermediate (HFRS 5–15) and high (HFRS > 15) HFRS did not predict increased costs on multivariate analysis.7 Similarly, in the retrospective NIS database study of 5,955 patients undergoing surgery for primary spinal or intradural cord tumors, Elsamadicy et al. demonstrated that while patients with increased HFRS had higher mean costs, increased frailty risk did not significantly associate with increased costs on multivariate analysis.8 Regarding overall frailty in geriatric patients, in the meta-analysis by Doody et al., the authors found no correlation between frailty prevalence and per-capita healthcare expenditures.23 Interestingly, however, our study found that increasing HFRS was an independent predictor of increased costs on multivariate analysis. These varying results highlight how different pathologies within spine oncology can be affected by patient frailty risk. Given a more standardized approach to spinal meningiomas compared to spinal metastases, frailty risk may have a greater impact on resource utilization. Therefore, a better understanding of how and why certain frailty risk components impact patient care may allow for a more targetable effort to alleviating the effects.
Given the adverse association between increased frailty risk and postoperative outcomes, novel strategies to aid the recovery of these patients are merited. One strategy in particular that has been gaining traction is the use of Enhanced Recovery After Surgery (ERAS) protocols. ERAS protocols incorporate a multifaceted care team and patient-centered recommendations and have been shown to reduce LOS, costs, and readmissions following surgery.38 Some studies have incorporated frailty risk into ERAS protocol recommendations. In a study discussing implementation of ERAS protocols for spine surgery, Chakravarthy et al. recommended the inclusion of preoperative frailty assessments in all geriatric patients.39 Additionally, in a retrospective cohort study of 32 geriatric patients at increased frailty risk undergoing 1–2 level transforaminal lumbar interbody fusion from 2015 to 2021, Porche et al observed that implementation of ERAS protocols significantly decreased LOS and time to return of function.40 Other studies have assessed the relationship between frailty risk and outcomes using ERAS protocols for non-spinal procedures. In a retrospective American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) cohort study of 711 patients who underwent abdominal surgeries from 2014 to 2017, Hampton et al. found that patients with increased mFI-5-defined frailty risk enrolled in ERAS protocols had significantly shorter LOS.41 Additionally, in a retrospective institutional study of 272 adult patients undergoing ileostomy closure incorporating ERAS protocols from 2006 to 2015, Wen et al. showed that Modified Frailty Index scores of 0 were significantly associated with early discharge on univariate analysis.42 Given these results, future studies are needed to assess the impact ERAS protocols on outcomes in patients at increased risk of frailty undergoing surgery for spinal tumors, as these protocols have the potential to greatly improve patient outcomes and healthcare resource utilization.
This study has limitations similar to all database studies which may impact the generalizability of the findings. First, the data were collected using ICD-10 codes which may be incomplete and contain reporting and classification biases. Second, given that the NIS database only contains information pertaining to a single hospital admission, we were unable to assess long-term outcomes within our patient population. Third, all data were analyzed retrospectively, severely limiting our ability to address potential confounders, such as social support or variations in surgical technique for a given procedure which may have impacted our findings. Fourth, our dataset did not contain information that could have implications for our results, including tumor burden, tumor mutation status, preoperative neurologic function, or imaging findings. Fifth, after stratifying by sex, we had relatively few male patients compared to female patients. This low relative number made identifying significant differences in comorbidities, perioperative variables, and outcomes between the Low and Intermediate-High frailty risk male cohorts particularly challenging. Last, we use the HFRS to define patient frailty risk. The HFRS, while useful for approximating risk of frailty, is not an all-encompassing definition. As a result, it is possible our results may not be able to be directly translated to some clinical settings. In spite of these limitations, this study uses a large US healthcare database to create new insights into the relationship between frailty risk and outcomes in patients undergoing surgery for spinal meningiomas.