A total of 10,812 patients over age 66 who were diagnosed with glioblastoma (GBM), had Medicare insurance and records, and were deceased prior to 2017 were included (Figure 1). 1,648 (15.24%) GBM patients had PC consultation at any point during their disease course prior to death. Early PC involvement was defined as consultation within 10 weeks of GBM diagnosis. Temel et al. enrolled and randomized their early PC patients with metastatic lung cancer within 8 weeks of diagnosis, whereas another group defined early PC as within 12 weeks of diagnosis for adult patients with solid malignancies [6, 10]. 676 (6.25%) GBM patients in our study met criteria for early PC consultation. 972 (8.99%) GBM patients had late PC consultation.
Following IPTW matching, there were no significant differences in demographics characteristics among groups of patients who either did not receive or received early or late PC. The average age across the three subgroups (no PC, early PC, and late PC) was 76 ± 6 years, and the majority of GBM patients were male (no PC: 54.7%; early PC: 51.9%; late PC: 54.%) (Table 1). The Elixhauser Index is a measure of mortality based on 31 co-morbidities, and most GBM patients within each subgroup had scores over 3 . There were no significant differences in tumor location among the PC subgroups. Furthermore, GBM patients within each PC subgroup underwent similar rates of biopsy, surgical resection, radiation therapy, and chemotherapy.
Patient Survival among Palliative Care Subgroups
Following IPTW matching, there were significant differences in the survival curves among GBM patients (P<0.001) (Figure 2). GBM patients who received early PC had a mean time to death from diagnosis as 3.99 ± 4.22 months, while GBM patients who received late PC had the longest mean time to death from diagnosis as 11.72 ± 13.20 months (Supplemental Table 1). Those who did not receive any PC during their disease had overall mean survival time of 7.76 ± 9.23 months.
Healthcare Utilization among Palliative Care Subgroups
Various aspects of healthcare utilization were categorized for each PC subgroup of GBM patients and divided into the last 30 days of life, the last 6 months prior to death, and overall rates occurring in the time from GBM diagnosis to death (Table 2).
In some areas of healthcare utilization, the subgroup of GBM patients who received late PC had the highest healthcare resource utilization over the entire disease course. This group demonstrated significantly higher average numbers of ER visits (3.46 ± 2.92, ICU admissions (1.50 ± 1.14), overall inpatient hospital admissions (4.48 ± 2.71), outpatient visits (19.38 ± 23.09), and length of stay in days (48.02 ± 48.73). On the other hand, patients in the late PC subgroup also had significantly greater use of hospice (2.25 ± 2.60) and HHA (1.32 ± 1.37).
In terms of Medicare payments and costs over the patients’ disease courses, the early PC group had significantly lower overall cost of HHA (1901 ± 3025, p<0.0001), cost of outpatient visits (6033 ± 11779, p<0.0001), and overall healthcare costs (82842 ± 52726, p<0.0001) compared to both the no PC and late PC groups. Conversely, the late PC subgroup demonstrated significantly higher overall costs of inpatient admissions (74091 ± 51143), outpatient visits (17690 ± 28623), and overall healthcare (129236 ± 76892).
When accounting for healthcare costs in the last 6 months prior to death for GBM patients who had received PC, the late PC subgroup had significantly greater overall Medicare payments (62650 ± 41081) compared to patients with early PC (47215 ± 30923). Likewise, in the last 6 months prior to death, the late PC subgroup had significantly greater numbers of ER visits (1.99 ± 1.69), ICU admissions (0.51 ± 0.85), hospital admissions (2.14 ± 1.99), outpatient admissions (9.95 ± 8.81), overall days for length of stay (23.02 ± 32.04) compared to GBM patients without PC and those who received early PC.
Some of these differences between early and late PC were abrogated when examining the last month prior to death, such as numbers of ICU admissions, hospital admissions, days for length of stay as well as HHA and hospice use. The healthcare costs associated with PC are significantly greater than for those who did not receive PC in the last month of life.
Trends in Palliative Care Utilization
From 1997 to 2015, there was an overall increase in PC use for GBM patients with a positive trend from 2.64% in 1997 to 42.54% in 2015 (Figure 3; Supplemental Table 2). For early PC consultation, the proportion of GBM patients meeting this criterion rose from 1.13% in 1997 to 20.63% by 2015. Likewise, the percentage of GBM patients who received late PC also increased from 1.51% in 1997 to 21.92% in 2015 (Supplemental Table 2). Similarly, for GBM patients who underwent biopsy or craniotomy, there was also an increase in PC use.