Abstract
Background
Middle meningeal artery embolization (MMAE) emerges as an alternative to conventional surgical drainage (CSD) for chronic subdural hematomas (cSDH). Several studies have suggested that MMAE improves the cost efficacy of cSDH treatment. However, further comprehensive analyses of the outcomes and healthcare costs of MMAE are necessary.
Methods
Merative MarketScan Research Database from 2017–2022 was used to compare demographics, reoperation rates, complications, healthcare utilization, and payments of patients being treated with CSD, CSD and adjunctive MMAE, or standalone MMAE for cSDH or nontraumatic subdural hemorrhage.
Results
From 2017–2022, there were 2108 patients who underwent CSD (n = 2015), or CSD+MMAE (n = 23) or MMAE only (n = 70). The median age of the surgical group was 61 years (IQR 53–73 years), the surgery plus MMAE was 67 years (56–77 years) and the MMAE group was 65 years (55–77 years). Median hospital days were significantly longer for the CSD (6 (IQR 5–7) days) and CSD + MMAE (7 (IQR 6–7) days) groups compared to MMAE only (0 days(IQR 0–1)(p < 0.0001). Median index hospitalization payments were significantly higher for the CSD+MMAE group ($74,568) compared to both CSD ($39,658) (p = 0.003) and MMAE groups ($22,286) (p < 0.0001). The total median payments at six-month follow-up for the CSD group were higher compared to CSD+MMAE ($11494 vs $7300, p = 0.0017) but not compared to MMAE only ($10,680, p = 0.08).
Conclusions
The reduced complications, infection rate, hospital utilization, and costs observed in this study support MMAE as a promising treatment option in the arsenal for cSDH management.
Keywords: Subdural, trauma, economics, embolization
Introduction
In the evolving treatment paradigm of chronic subdural hematoma (cSDH), middle meningeal artery embolization (MMAE) emerges as a pivotal adjunct and alternative to conventional surgical drainage (CSD). Three major randomized clinical trials (STEM, EMBOLISE, MAGIC-MT) have demonstrated the significant benefit of MMAE in terms of reduced recurrence or progression of cSDHs.1–3 Additionally, Rai et al. estimated that potentially MMAE eligible patients, comprised of both non-traumatic and traumatic non-acute subdural hematomas (about 140,000 cases per year or 41/100,000 persons/year), could exceed the number of large vessel occlusion patients (about 102,000 cases per year, or 31/100,000 persons/year). 4 With these promising results comes a rising need to understand how the increased use of MMAE might shift the economic landscape of cSDH management.
The current economic literature of cSDH treatment is heterogeneous but suggests that MMAE may have similar or improved costs when compared to surgery. Salih et al. found that there was similar total hospitalization (open surgery: $60,598 ± 61,315; MMAE: $71,569 ± $37,813) and follow-up associated costs comparing the two groups. 5 However, there were greater procedural costs with the addition of MMAE to surgical evacuation ($38,255 ± $11,859 vs $11,206 ± $7888; p < 0.001). 5 In another study, Catapano et al. reported MMAE-only was associated with a lower total hospital cost compared to surgical treatment (mean difference −$32,776; 95% CI −$52,766 to −$12,787; p < 0.001) and that unexpected additional treatment was the only significant contributor to total hospital cost (mean difference $96,357; 95% CI $73,886 to $118,827; p < 0.001). 6
On a larger scale, Tong et al. 7 examined 9532 patients with cSDH using the Nationwide Readmissions Database. Of these patients, 95.7% were treated with traditional surgical drainage/evacuation and 4.3% were treated with MMAE and had similar functional outcomes (favorable outcomes, 80.9% vs 74.8%; p = 0.224). Cost-efficacy measures using propensity matching demonstrated that MMAE had a lower 90-day retreatment rate (2.6% vs 9.0%; p = 0.001), shorter length of hospital stays (4.61 ± 6.19 vs 5.73 ± 5.76 days; p = 0.037), but higher costs ($119,757.71 ± 90,378.70 vs $75,745.55 ± 100,701.28; p < 0.001) when compared with conventional treatment. 7 Compared to conventional treatment, MMAE yielded incremental cost-effectiveness ratios of $15,199.8/quality-adjusted life year and additional 1.3 quality-adjusted life years compared to conventional treatment. 7 This suggests that the higher procedural costs of MMAE may be economically balanced by better functional outcomes.
Further analysis is needed to examine the comprehensive healthcare costs associated with MMAE, including the quantitative analysis of the financial impacts of reduced reoperation and functional outcomes. This retrospective study compares the demographics, reoperation rates, complications, healthcare utilization, and payments of patients being treated with CSD, CSD and adjunctive MMAE, or standalone MMAE for cSDH. Through an evaluation of both direct and indirect costs, this investigation aims to provide healthcare decision-makers with a nuanced understanding of the economic and clinical benefits of adjuvant MMAE. These data are essential for assessing how integrating MMAE into standard cSDH treatment protocols may improve patient outcomes and cost efficiency.
Methods
Data source
For this study, we used Merative MarketScan Research Database, a claims-based healthcare database used in medical, public health, and epidemiology research for decades 8 and previously published by our group.9–13 MarketScan has several advantages compared to other databases, as it contains longitudinal data on inpatient and outpatient encounters, prescription information, healthcare utilization, and payment information. 14 Medical claims from the beneficiary, or their dependent, are tracked using a unique encrypted ID and linked across different databases and healthcare systems. 8 Individuals enter the data when they enroll with their insurance and they exit when that coverage ends. We hold a license for neurological or neurosurgical conditions across three insurance types (private, Medicaid, and Medicare supplemental). For this study, we used MarketScan records from 2017–2022 to extract patients who underwent CSD and/or MMAE for cSDH or nontraumatic subdural hemorrhage (ntSDH) using the International Classification of Disease, 10 revision (ICD-10) and Current Procedural Terminology, 4th edition (CPT-4) claim codes.
Study population
The study population included patients who underwent treatment for cSDH (ICD-10 I62.03) and ntSDH (ICD-10 I62.00). Three study groups were formed based on treatment within three months of diagnosis: (1) CSD-only including craniotomy, craniectomy, or burr hole (CPT-4 codes 61312, 61314, 61108, 61154, 61156); (2) CSD (previously mentioned codes) with adjunctive MMAE (CPT-4 codes 61624, 61626) within one month of surgery; and (3) MMAE-only (CPT-4 codes 61624, 61626). Patients younger than 18 years old were excluded. Additionally, diagnoses of cerebral arteriovenous malformation (ICD-10 Q28.2), malignant neoplasm of the brain (ICD-10 C71), malignant neoplasm of the head, face, or neck (ICD-10 C76.0), epistaxis (ICD-10 R04.0), and cerebral aneurysm/acquired cerebral arteriovenous fistula (ICD-10 I67.1) were excluded to eliminate any confounding external carotid embolization procedures. Only individuals continuously enrolled from three months prior to index to six months following index were retained for this dataset. For those who had CSD-only, index was the time of surgery. For those who had both CSD and MMAE, index covered the time of CSD to the time of MMAE. For those who had MMAE-only, index was the time of MMAE.
Outcome measures
Patient characteristics, including age, sex, and insurance, were noted at index. Comorbidities were captured through the Elixhauser Comorbidity Index score 15 calculated using an adaptation 16 of ICD-10 codes. The Elixhauser Comorbidity Index, which contains 31 comorbid conditions, has been proven in the stroke and surgical literature to accurately predict risk-adjusted mortality in the inpatient setting.17,18 For each individual, the three months leading to index were screened for these comorbidities. Primary outcomes included reoperation rates and postoperative complications (renal, cardiac, nervous system, cerebrovascular, deep vein thrombosis/pulmonary embolism, pulmonary, infection, wound, pneumonia, myocardial infarction, acute kidney injury, pressure ulcers, sepsis, and urinary tract infection). Secondary outcomes were focused on healthcare utilization metrics such as index hospitalization length of stay, index hospitalization payments, six-month hospital admissions, emergency room visits, outpatient services, medication refills, and total payments. The six-month follow-up time started at index.
Statistical analysis
Age was summarized with median and compared across the three groups using univariate quantile regression. Sex, insurance, and comorbidities (0, 1, 2, 3, or more) were summarized with percentage and compared across groups using the chi-square test. Since there were differences in characteristics across treatment modalities, outcomes comparisons were performed with adjusted regression models including all the descriptors (age, sex, insurance, comorbidities) in addition to the group variable. For hospital admission, emergency room visits, reoperation, and complications, logistic regression was used. For hospital length of stay, number of services, and number of refills, quantile regression was used. All tests were two-sided, and the significance level was set to 5%. Statistical analyses were performed in SAS 9.4 (SAS Inc, Cary, NC).
Results
Patient characteristics
Three study groups were formed based on treatment: CSD-only (n = 2015), CSD+MMAE (n = 23), and MMAE-only (n = 70). Patient characteristics are presented in Table 1. The median age was 61 years [Q1–Q3: 53–73] for the CSD-only group, 67 years [Q1–Q3: 56–77] for the CSD+MMAE group, and 65 years [Q1–Q3: 55–77] for the MMAE-only group. There were no significant differences in age between groups. We determined the sex characteristics for each treatment modality and found that the CSD+MMAE group (9%) had significantly less females than the CSD-only (33%; p = 0.0272) and MMAE-only (37%; p = 0.0194) groups.
Table 1.
Demographics and patient characteristics.
| Patients with cSDH treated with | |||||||
|---|---|---|---|---|---|---|---|
| CSD [1] | CSD + MMAE [2] | MMAE only [3] | p-values | ||||
| n = 2015 | n = 23 | n = 70 | [2] vs [1] | [3] vs [1] | [3] vs [2] | ||
| Age, median [Q1–Q3] | 61 [53–73] | 67 [56–77] | 65 [55–77] | 0.1886 | 0.1178 | 0.7129 | |
| Sex, female, % | 33% | 9% | 37% | 0.0272 | 0.4592 | 0.0194 | |
| Insurance | Commercial, % | 36% | 30% | 29% | 0.5664 | 0.1917 | 0.8644 |
| Medicaid, % | 35% | 17% | 31% | 0.0946 | 0.5789 | 0.2004 | |
| Medicare, % | 29% | 52% | 40% | 0.0203 | 0.0521 | 0.3085 | |
| Elixhauser score | 0, % | 4% | 4% | 6% | 0.8317 | 0.3384 | 0.8016 |
| 1, % | 6% | 4% | 3% | 0.6906 | 0.2433 | 0.7275 | |
| 2, % | 7% | 0% | 1% | 0.9793 | 0.1084 | 0.9819 | |
| 3+, % | 83% | 92% | 90% | 0.3127 | 0.1395 | 0.8545 | |
cSDH: chronic subdural hematoma; CSD: conventional surgical drainage; MMAE: middle meningeal artery embolization.
Regarding insurance type, there were no statistically significant differences in representation of commercial insurance providers between the three groups (CSD-only: 36%, CSD+MMAE: 30%, MMAE-only: 29%). There was no difference between Medicaid provision between the three groups (CSD-only: 35%, CSD+MMAE: 17%, MMAE-only: 31%). Significantly more patients received Medicare insurance in the CSD+MMAE group (52%) compared to CSD-only (29%; p = 0.02).
Reoperation rates
Reoperation rates were lowest for patients treated with CSD-only (0%), but there were no significant differences in rates across groups (CSD+MMAE: 4%, MMAE-only: 5%) (Table 2). No instances of new MMAE (0%) were observed for any group.
Table 2.
Reoperation.
| Patients with cSDH treated with | ||||||
|---|---|---|---|---|---|---|
| CSD [1] | CSD + MMAE [2] | MMAE only [3] | p-values | |||
| n = 2015 | n = 23 | n = 70 | [2] vs [1] | [3] vs [1] | [3] vs [2] | |
| 6 months | ||||||
| New CSD, % | 0% | 4% | 5% | 0.3127 | 0.1395 | 0.8545 |
| New MMAE, % | 0% | 0% | 0% | |||
cSDH: chronic subdural hematoma; CSD: conventional surgical drainage; MMAE: middle meningeal artery embolization.
Medical complications
Complication results are shown in Table 3. At index hospitalization, the percentage of patients with at least one complication was significantly higher for CSD-only (71%) compared to CSD+MMAE (30%; p = 0.0015) or MMAE-only (44%; p = 0.021). Additionally, the percentage of patients with at least one complication at index hospitalization was significantly higher for MMAE compared to CSD+MMAE (p = 0.0176). The incidence of renal complications/failure at index hospitalization was significantly higher in the CSD-only group (12%) compared to the MMAE-only group (0.03%; p = 0.0096). The incidence of urinary tract infections was also significantly higher at index in the CSD-only group (15%) compared to both CSD+MMAE (2%) and MMAE-only (5%; both p < 0.05). There were more cerebrovascular complications in the CSD-only group (50%) when compared to the MMAE-only group (26%; p < 0.0001) and the CSD+ MMAE group (27%, p = 0.0421). However, pulmonary complications were more frequently observed in the MMAE-only group (14%) than the CSD+MMAE group (5%; p = 0.0408). The infection rate was higher for CSD-only (16%) than both CSD+MMAE (2%; p = 0.0285) and MMAE-only groups (5%; p = 0.0438).
Table 3.
Complications.
| Patients with SDH treated with | ||||||
|---|---|---|---|---|---|---|
| CSD [1] | CSD + MMAE [2] | MMAE only [3] | p-values | |||
| n = 2015 | n = 23 | n = 70 | [2] vs [1] | [3] vs [1] | [3] vs [2] | |
| At index a | ||||||
| Renal, % | 12% | 0% | 3% | 0.9737 | 0.0096 | 0.9761 |
| Cardiac, % | 0% | 0% | 0% | |||
| Cerebrovascular, % | 50% | 27% | 26% | 0.0421 | 0.0162 | 0.9372 |
| Nervous system, % | 0% | 1% | 2% | 0.9812 | 0.9804 | 0.6354 |
| DVT/PE, % | 3% | 0% | 3% | 0.9773 | 0.9775 | 0.9773 |
| Pulmonary, % | 19% | 5% | 14% | 0.0635 | 0.5371 | 0.0408 |
| Infection, % | 16% | 2% | 5% | 0.0285 | 0.0438 | 0.2667 |
| Wound, % | 0% | 0% | 0% | |||
| Pneumonia, % | 11% | 2% | 5% | 0.1191 | 0.2683 | 0.2701 |
| Myocardial infarction, % | 0% | 0% | 0% | |||
| Kidney failure, % | 12% | 0% | 3% | 0.9737 | 0.0096 | 0.9761 |
| Pressure ulcer, % | 0% | 0% | 0% | |||
| Sepsis, % | 10% | 0% | 3% | 0.9759 | 0.056 | 0.9783 |
| Urinary tract infection, % | 15% | 2% | 5% | 0.0292 | 0.0475 | 0.259 |
| At least one of the above, % | 71% | 30% | 44% | 0.0015 | 0.021 | 0.0176 |
| 6 months | ||||||
| Renal, % | 0% | 0% | 0% | |||
| Cardiac, % | 0% | 0% | 0% | |||
| Cerebrovascular, % | 28% | 44% | 29% | 0.1761 | 0.931 | 0.0091 |
| Nervous system, % | 3% | 1% | 2% | 0.4895 | 0.5145 | 0.7572 |
| DVT/PE, % | 3% | 3% | 5% | 0.9149 | 0.4307 | 0.2527 |
| Pulmonary, % | 0% | 5% | 4% | 0.9789 | 0.9792 | 0.6817 |
| Infection, % | 11% | 9% | 8% | 0.7645 | 0.6047 | 0.7541 |
| Wound, % | 4% | 2% | 3% | 0.7251 | 0.9685 | 0.5824 |
| Pneumonia, % | 0% | 0% | 0% | |||
| Myocardial infarction, % | 0% | 0% | 0% | |||
| Kidney failure, % | 0% | 0% | 0% | |||
| Pressure ulcer, % | 0% | 0% | 0% | |||
| Sepsis, % | 0% | 2% | 4% | 0.9807 | 0.98 | 0.5436 |
| Urinary tract infection, % | 11% | 9% | 8% | 0.7536 | 0.606 | 0.7787 |
| At least one of the above, % | 53% | 56% | 43% | 0.8462 | 0.3283 | 0.0416 |
CSD: conventional surgical drainage; MMAE: middle meningeal artery embolization; DVT/PE: deep vein thrombosis/pulmonary embolism.
For those who had CSD, index is the time of surgery. For those who had both CSD and MMAE, index covers the time of surgery to the time of MMAE. For those who had MMAE alone, index is the time of MMAE.
At six months, the percentage of patients with at least one complication was significantly lower for MMAE-only (43%) than the CSD+MMAE group (56%; p = 0.0416), but not different from CSD-only (53%). There were significantly more cerebrovascular complications at six-month follow-up in the CSD+MMAE group compared to the MMAE-only group (44% vs 30%; p = 0.018).
Hospital utilization and payments
Healthcare utilization and costs at index hospitalization and six-month follow-up are presented in Table 4. ICD-10 codes for complications are in Table 5. For index hospitalization, the median length of stay was 6 days (Q1–Q3: 5–7) for the CSD-only group, 7 days (Q1–Q3: 6–7) for the CSD+MMAE group, and 0 days (Q1–Q3: 0–1) for the MMAE-only group. Length of stay for MMAE-only was significantly shorter than length of stay for CSD+MMAE or CSD-only (both p < 0.0001). Total median index hospitalization payments were significantly higher for the CSD+MMAE group ($74,568) compared to both CSD-only ($39,658; p = 0.003) and MMAE-only groups ($22,286; p < 0.001) (Figure 1).
Table 4.
Healthcare utilization and cost.
| Patients with SDH treated with | ||||||
|---|---|---|---|---|---|---|
| CSD [1] | CSD + MMAE [2] | MMAE only [3] | p-values | |||
| n = 2015 | n = 23 | n = 70 | [2] vs [1] | [3] vs [1] | [3] vs [2] | |
| Index a | ||||||
| Hospital days, median [Q1–Q3] | 6 [5–7] | 7 [6–7] | 0 [0–1] | 0.1944 | <0.0001 | <0.0001 |
| Total payments, median [Q1–Q3] | 39658 [16962–68217] | 74568 [74038–103260] | 22286 [120–51110] | 0.003 | <0.0001 | <0.0001 |
| 6 months | ||||||
| Had ER visits, % | 24% | 34% | 43% | 0.3524 | 0.0552 | 0.1103 |
| Were hospitalized, % | 9% | 18% | 20% | 0.2841 | 0.1413 | 0.5256 |
| No. of outpatient services, median [Q1–Q3] | 59 [48–66] | 50 [39–53] | 63 [50–69] | 0.1957 | 0.9046 | 0.3199 |
| No. of prescription refills, median [Q1–Q3] | 15 [13–18] | 14 [12–16] | 11 [10–14] | 0.3632 | 0.0442 | 0.6766 |
| Total payment, median [Q1–Q3] | 11494 [3572–12779] | 7300 [4686–7897] | 10680 [2626–11991] | 0.0017 | 0.6057 | 0.0804 |
CSD: conventional surgical drainage; MMAE: middle meningeal artery embolization.
For those who had CSD, index is the time of surgery. For those who had both CSD and MMAE, index covers the time of surgery to the time of MMAE. For those who had MMAE alone, index is the time of MMAE.
Table 5.
Complication coding.
| Complication | ICD-10 |
|---|---|
| Renal | N17, N99.89 |
| Cardiac | I21, I97.7, I97.8 |
| Nervous system | G97 |
| Cerebrovascular | I61, I62, I63, I64, I65, I66, I67, I68, I69 |
| DVT/PE | I26, I80, I81, I82 |
| Pulmonary | J81.0, J80, J95.1, J95.2, J95.3, J95.8, J96 |
| Infection | N30.00, N30.01, N30.90, N30.91, N39.0 |
| Wound | T81.31, T81.4, T81.8 |
| Pneumonia | J13, J14, J15, J16, J17, J18 |
| Myocardial infection | I21 |
| Acute kidney failure | N17 |
| Pressure ulcers | L89 |
| Sepsis | A41.81, A41.9, R65.2 |
| Urinary tract infection | N10, N11, N12, N15, N16, N28.84, N28.85, N28.86, N30, N35.1, N37, N39.0 |
DVT/PE: deep vein thrombosis/pulmonary embolism.
Figure 1.
Median payments at index hospitalization.
Median total payments at six months were $11,949 [Q1–Q3: $3572–12,779] for the CSD-only group, $7300 [Q1–Q3: $4686–7897] for the CSD+MMAE group, and $10,680 [Q1–Q3: $2626–11,991] for the MMAE-only group. The CSD+MMAE group had significantly lower total payments at six months than the CSD-only group (p = 0.0017) (Figure 2).Regarding six-month follow-up healthcare events, the only significant finding was that patients in the MMAE-only group had fewer prescription medication refills (11 [Q1–Q3: 10–14]) than patients in the CSD-only group (15 [Q1–Q3:13–18]; p = 0.0017).
Figure 2.
Median total payments at six-month follow-up.
Discussion
The present study compares the outcomes of three common treatment modalities for cSDH: CSD, the combination of CSD and MMAE, and standalone MMAE. To our knowledge, no study has reported a cost-effectiveness comparison of these three treatment strategies. These results provide greater insight into the cost-effectiveness and healthcare resource effects of these treatments in this large neurosurgical patient population.
Patient characteristics
The study population had no significant age differences observed between the groups. The proportion of female patients was significantly lower for the CSD+MMAE group (9%) than CSD-only (33%; p = 0.0272) and MMAE-only (37%; p = 0.019) treatment groups. The male majority observed in our study is consistent with the male predilection of cSDH with risk factors such as higher incidence of head trauma.19,20 This demographic discrepancy may have implications for the generalizability of the findings and suggests a potential area for further investigation to understand sex-specific responses to these treatments.
Reoperation rates
The reoperation rates at six months were low across groups. The low reoperation rates in our study, 4% in the CSD+MMAE group and 5% in the MMAE-only group, are consistent with reoperations in MMAE patients reported as 4–7% in the literature.21,22 These findings support the potential of MMAE, both as an adjunct or standalone procedure in appropriate patient populations. However, the lack of reoperations or new MMAEs in the CSD-only group (within 6-month follow-up) is inconsistent with previously reported reoperation rates occurring in up to 30% of surgically treated cSDH patients.23,24 This may be due to selection bias and lack of patient-level data reporting such as physician decision making, radiographic recurrence or changes in neurologic status, and thus the generalizability of this retrospective data may be inherently limited.
Medical complications
At baseline, there were no differences in Elixhauser Comorbidity Index between the three groups, with higher preponderance of Elixhauser scores of 3+ for all groups. These findings may be reflective of the elderly and inherently comorbid patients who have a higher likelihood of developing cSDH.7,25,26 Interestingly, the percentage of patients with at least one complication at index hospitalization was highest for CSD-only (70%) followed by MMAE-only, and lastly CSD+MMAE (Table 3). More specifically, patients undergoing standalone CSD treatment had a higher percentage of renal complications/failure compared to the MMAE-only group, as well as a higher incidence of urinary tract infections compared to both groups. These results may be confounded by the shorter hospital length of stay in MMAE-only patients, or a baseline presence of renal disease within the CSD-only group. Treatment with MMAE-only had the lowest rate of cerebrovascular complications both at index hospitalization and at six months. At index, cerebrovascular complications were significantly higher in the CSD-only treatment group compared to the CSD+MMAE and MMAE-only groups. These results could reflect sequelae of more severe neurologic injury leading to CSD upfront. At six-month follow-up, the CSD+MMAE group had significantly more cerebrovascular complications compared to the MMAE-only group, but CSD+MMAE and CSD-only showed similar rates. These findings underscore the safety of standalone MMAE in the appropriate patients, highlighting its feasibility as a less-invasive alternative to traditional surgical methods.
Hospital utilization and payments
Length of stay between the treatment groups showed a marked difference, with the MMAE-only group having a significantly shorter stay (0 days) compared to both the CSD-only (6 days) and CSD+MMAE groups (7 days). This substantial reduction in hospital length of stay for the MMAE-only group could reflect the less-invasive nature of the procedure. This finding could also be from billing MMAE as an overnight-admission or as an outpatient procedure. This is consistent with a study by Nia et al. that showed a significantly lower length of hospital stay for primary MMAE (7.74 [95% CI: 6.04–9.44]) than for primary surgery (30.20 [26.38–34.02], p < 0.0001). 26 Other studies have supported MMAE performed in an outpatient setting or after overnight observation and indicated length of stay may also be influenced by the choice of anesthetic/sedation or the patient's disposition after the procedure.27,28 In contrast, another study using the National Inpatient Sample (NIS) database reported MMAE patients accrued significantly greater hospital charges (p < 0.001) and had longer lengths of stay (13 days) compared to surgically treated patients (8 days, p = 0.023). 29 However, this study included patients from 2012–2018 when MMAE in the United States was still a nascent procedure and may not reflect the current practice of MMAE.29,30 Historically, patients with non-operative cSDHs may have been observed with serial imaging and/or medical management rather than undergo MMAE, which could be associated with higher procedural costs.31,32
Despite higher upfront costs, CSD+MMAE is likely more economical than CSD alone at six-month follow-up. Additionally, the lower cost and shorter hospital stay for the MMAE-only group supports its cost effectiveness in the appropriate patients. However, the outpatient/follow-up costs are much smaller compared to inpatient costs for all three groups. Our findings are consistent with those of Catapano et al. who reported decreased healthcare costs and readmissions in a 1-year single institution analysis. 6 Our findings are also supported by Tong et al. which also reported shorter length of stay and superior cost-effectiveness of MMAE compared to conventional treatment using the current US willingness-to-pay threshold. 7 Interestingly, the cost disparities between CSD+MMAE and CSD-only costs at six months do not appear to be driven by readmissions, reoperations, or emergency room visits in our sample as the differences did not reach statistical significance. There could be hidden costs not accounted for in our study that attribute to this difference such as utilization of outpatient imaging.
Limitations
This retrospective study using the MarketScan database offers an opportunity to extract a large sample size with economic data and outcomes. One limitation is possible inconsistencies in ICD-9 and ICD-10 coding and reporting from providers and institutions. Other major limitations stem from insufficient healthcare data provided through the MarketScan database. For example, we were unable to access cross-sectional imaging, limiting our analysis of key radiographic features of cSDHs such as chronicity of blood, hematoma thickness, midline shift, and Hounsfield units of the hematomas. Neurological exams and clinical assessments, that often drive treatment modality, were also unavailable. Additionally, there was no access to the operative reports of the endovascular or open surgical procedures. Therefore, we could not determine agents used for embolization (liquids, particles, or coils), a factor likely effecting both healthcare costs and procedural success.6,33–35 Lastly, the relatively small sample size for the CSD+MMAE (n = 23) and MMAE-only (n = 70) groups in comparison to the CSD-only group (n = 2015) due to selecting patients that had at least six-month follow-up may introduce bias and limit the statistical power and generalizability of the findings. The discrepancy in the size of the CSD+MMAE and MMAE only groups could also reflect not having data from 2023–2024, as there is a suggested recent uptick in number of MMAEs being performed in parallel with the randomized clinical trials.4,30 Future prospective studies with larger sample sizes and longer follow-up periods are necessary.
Conclusion
MMAE, whether alone or in combination with CSD, offers a treatment alternative for cSDH with reduced complications, length of stay, and lower healthcare costs. These efficiencies in hospital utilization and cost position MMAE as a promising treatment option in the arsenal for cSDH management. Larger scale observation of these treatment groups with radiographic and clinical data is required to comprehensively analyze other clinical outcomes that may contribute to the cost efficiency of cSDH treatment.
Footnotes
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Ethical approval: This study was approved by the University of Louisville School of Medicine IRB, IRB#10.0559. There was no patient research consent applicable to this project as the data was acquired from a third-party healthcare claims database providing deidentified data.
Funding: The authors received no financial support for the research, authorship, and/or publication of this article.
ORCID iD: Kevin John https://orcid.org/0000-0002-2299-0434
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