Time trends in cancer and dementia related hospital admissions among Medicare fee-for-service population, 2013–2018

1. Introduction

Cancer and dementia are two complicated morbidities that are commonly found in older adults and require substantial healthcare resources.[1,2] Caring for patients with the co-presence of cancer and dementia, who suffer from impaired cognitive function with complex medical needs, is challenging for clinicians, caregivers, and healthcare systems. With the aging US population, the increasing number of older adults with these two comorbid conditions is likely to place a high demand on hospitals. Meanwhile, the shift of care delivery from inpatient to settings such as outpatient and homes, increasing reliance on family caregivers, and improved community care support may help reduce unnecessary hospitalizations.[3–5] It is important to understand the pattern of hospitalization, which is one of the major drivers of healthcare costs and high financial and caregiving burden for patients and their families, among the growing population with cancer and dementia. While there has been extensive research on the incidence, prevalence, and healthcare utilization among older adults with either cancer or dementia, existing literature examining older adults with both conditions is scarce and limited in scope. [1,2,6,7] In particular, no national estimates exist regarding the hospitalization rates among older adults with comorbid cancer and dementia. To fill this gap, we examined the national and state-level trends in hospitalization rates among Medicare fee-for-service (FFS) beneficiaries with the co-presence of a major cancer (breast, prostate, lung, and colorectal) and dementia diagnoses. We hypothesized a growing trend of inpatient use among this population during the years 2013–2018. Due to the heterogeneity in cancer-specific prognosis and treatment, we also examined the trend of hospitalizations among this population by cancer types.

2. Methods

We analyzed 2013–2018 inpatient claims data (the Limited Dataset Files) from the Centers for Medicare and Medicaid Services. This secondary data analysis was exempted human subject research by the author’s Institutional Review Board. We identified Medicare FFS beneficiaries aged 65 years or older who were hospitalized with any of the four major cancer types (breast, prostate, lung, and colorectal), and Alzheimer’s disease or related dementias, using the primary and all available secondary diagnosis records in the same inpatient discharge claims, according to the Chronic Conditions Data Warehouse algorithms (Supplemental Table S1). [8]

The primary outcome of interest was hospitalization rates (admissions per 10,000 Medicare FFS beneficiaries) calculated using the number of hospitalizations with the co-presence of cancer and dementia as the numerator, and the total number of Medicare FFS beneficiaries aged 65 years or older as the denominator. For hospitalization rates among patients with breast or prostate cancer, sex-specific denominator population was used. We calculated the hospitalization rate at both national and state level. We also calculated the hospitalization rate for each disease alone. In addition, we reported the proportion of hospitalizations with the co-presence of cancer and dementia among all hospitalizations with either cancer or dementia separately. Finally, we summarized patient-level characteristics.

Time trends of hospitalization rates (P for trend) were tested using linear regressions, where the hospitalization rate was a function of calendar year and the regression coefficient of calendar year was tested to assess whether it was associated with the hospitalization rate. The time trend was examined for the overall population at both the national and state level, as well as by cancer types at the national level. All analyses were performed using SAS version 9.4 and R version 4.0.2.

3. Results

Between 2013 and 2018, 870,311 (13.6%) out of all 6,401,439 hospitalizations among patients with a major cancer were also accompanied by a dementia diagnosis, and the proportion increased slightly from 13.3% (N = 146,927/1,108,662) in 2013 to 13.6% (N = 142,098/1,041,313) in 2018 (P = 0.03; Supplemental Table S2). Of all 7,915,702 hospitalizations among patients with a dementia diagnosis, approximately 11.0% (N = 870,311) were among patients with the co-presence of cancer and dementia, and the proportion increased slightly from 10.8% (N = 146,927/1,358,957) in 2013 to 11.1% (N = 142,098/1,283,294) in 2018 (P = 0.05, Supplemental Table S2).

A large proportion of the patients with the co-presence of cancer and dementia were of advanced age (51.4% aged above 84 years, Table 1), had multiple comorbidities (65.7% with three or more comorbidities), and were female (52.6%). Approximately 75.9% of these patients were transferred from the emergency department (ED), and 39.4% were discharged to skilled nursing facilities. They also tended to have unfavorable inpatient outcomes, such as inpatient stays longer than four days (62.5%) and high risks of readmission and mortality (Table 1). There were also notable differences by cancer types. For example, patients with dementia and lung cancer had the highest inpatient mortality (7.1% vs 4.04.7 for other cancers) despite being younger (33% vs >51% of patients aged above 84 years). The selected sociodemographic and clinical characteristics (i.e., age, race/ethnicity, readmission risk group, and comorbidity groups) of the study population remained relatively stable during 2013–2018 (Supplemental Table S3).

Table 1.

Characteristics of Medicare fee-for-service beneficiaries who were hospitalized with the co-presence of at least one major cancer (breast, prostate, lung, or colorectal) and dementia diagnoses, as well as the co-presence of a specific major cancer and dementia, 2013–2018.

Characteristics	Major Cancer and Dementia	Prostate cancer and Dementia	Breast cancer and Dementia	Colorectal cancer and Dementia	Lung cancer and Dementia
N	870,311	293,743	302,092	193,440	121,088
Sex
Male	47.4%	100.0%	0.0%	42.8%	45.5%
Female	52.6%	0.0%	100.0%	57.2%	54.5%
Age group (year)
65–69	3.1%	2.2%	2.8%	2.7%	6.4%
70–74	7.9%	6.8%	7.2%	6.7%	14.1%
75–79	14.7%	14.9%	13.1%	12.9%	21.2%
80–84	22.9%	24.7%	21.5%	21.5%	24.8%
>84	51.4%	51.5%	55.5%	56.2%	33.6%
Race/Ethnicity
Non-Hispanic White	84.4%	81.0%	86.9%	84.9%	85.9%
Non-Hispanic Black	11.9%	15.2%	9.9%	10.8%	10.6%
Hispanic	1.4%	1.6%	1.2%	1.6%	1.0%
Other	2.3%	2.2%	1.9%	2.7%	2.5%
Number of comorbidities
0	2.7%	3.1%	2.7%	2.6%	2.1%
1–2	31.6%	33.5%	32.6%	30.3%	26.2%
3	23.0%	23.1%	23.5%	23.0%	22.2%
≥4	42.7%	40.3%	41.3%	44.1%	49.6%
Transfer from Emergency Department	75.9%	75.4%	77.1%	74.8%	75.7%
Readmission risk group
−4 ≤ scores ≤6	18.6%	19.1%	21.3%	17.3%	12.2%
6 < scores ≤16	30.1%	28.9%	32.0%	29.6%	29.4%
16 < scores ≤29	28.6%	28.3%	27.6%	29.2%	31.4%
scores >29	22.7%	23.7%	19.0%	23.9%	27.1%
Mortality risk group
−25 ≤ scores ≤0	29.7%	29.2%	33.2%	28.7%	23.3%
0 < scores ≤6	18.6%	18.8%	18.2%	17.8%	20.8%
6 < scores ≤14	29.5%	29%	29.5%	29.9%	30.2%
scores > 14	22.3%	23.1%	19.2%	23.5%	25.7%
In-hospital mortality	4.7%	4.5%	4.0%	4.7%	7.1%
Length of stay
1 ≤ days≤2	8.0%	8.2%	8.3%	7.5%	7.3%
2 < days≤4	29.5%	29.3%	31.7%	28.2%	26.6%
4 < days≤8	38.6%	38.3%	39.1%	38.6%	38.5%
days> 8	23.9%	24.3%	20.9%	25.8%	27.6%
Discharge type
Skilled Nursing Facility	39.4%	38.6%	41.8%	40.3%	33.5%
Home	18.9%	19.8%	18.7%	18.3%	17.9%
Other	41.7%	41.6%	39.5%	41.4%	48.6%

Notes: Data sources were based on standard Analytical Files (Medical Claims) Limited Dataset Files from Medicare (https://www.cms.gov/Research-Statistics-Data-and-Systems/Files-for-Order/LimitedDataSets/StandardAnalyticalFiles). Only fee-for-service Medicare beneficiaries aged 65 and over were included. Patients who had HMO or did not have continuous Medicare Part A and B coverage during 12 months prior to each hospitalization (11.0%), who were younger than 65 years old (5.3%), and those with missing race/ethnicity information (0.4%) were excluded. Cancer and dementia were defined by algorithms from the Chronic Condition Data Warehouse (https://www2.ccwdata.org/web/guest/condition-categories); Elixhauser comorbidity (excluding METS, TUMOR, LYMPH, and NEURO), readmission risk, and mortality risk scores were calculated using algorithms from the Healthcare Cost and Utilization Project (https://www.hcup-us.ahrq.gov/tools_software.jsp); Different admissions from the same patients were counted as separate data points.

At the national level, the hospitalization rate of patients with the co-presence of a major cancer and dementia remained stable, ranging from 53.2 to 50.0 admissions per 10,000 Medicare FFS beneficiaries between 2013 and 2018 (P = 0.05, Fig. 1). The median hospitalization rate at the state level also remained stable (P = 0.25), ranging from 49.2 (interquartile range, IQR = 37.6–57.6) to 47.8 (IQR = 33.7–53.3) admissions per 10,000 Medicare FFS beneficiaries between 2013 and 2018. Some variations were seen across states (Supplemental Fig. S1). We found a similar stable trend for breast cancer (from 32.6 to 31.4, P = 0.09) and prostate cancer (from 40.9 to 38.5, P = 0.16), while there was a decreasing trend (from 12.6 to 10.6, P < 0.001) for colorectal cancer and an increasing trend for lung cancer (from 7.1 to 7.4, P = 0.04) (Fig. 1). As shown in Supplemental Table S4, the hospitalization rate between 2013 and 2018 decreased from 237 to 215 admissions per 10,000 Medicare FFS beneficiaries (P = 0.001) among patients with any major cancer only, and from 439 to 401 admissions per 10,000 Medicare FFS beneficiaries among patients with dementia only (P = 0.001).

Fig. 1.

Time trend in the national and state-level hospitalization rates among patients with co-presence of a major cancer (breast, prostate, lung, or colorectal) and dementia diagnoses, 2013–2018. Hospitalization rates were calculated as admissions per 10,000 Medicare fee-for-service beneficiaries aged 65 and over. For hospitalization rates among patients with breast or prostate cancer, sex-specific denominator population was used.

4. Discussion

In this initial examination of how older adults with comorbid cancer and dementia are utilizing the healthcare system, we found that approximately 14% of hospitalizations with a major cancer diagnosis during 2013–2018 also had a dementia diagnosis. We also found an overall stabilizing trend of the hospitalization rate among patients with the co-presence of cancer and dementia during 2013–2018 at both the national and state level.

Given the increasing prevalence of cancer and dementia (about 3.8% increase for the four major cancers and 2% increase for dementia between 2013 and 2018 [8]) and the decreasing hospitalization rate for cancer alone and dementia alone (this study), the stable trend in the hospitalization rate for patients with the co-presence of cancer and dementia is noteworthy. Two potential explanations include (1) the shift of disease management and treatment away from inpatient to other settings and (2) potential successes in reducing unnecessary hospitalizations among this population. Studies have shown that patients with cancer and dementia, their families and caregivers, and their providers tend to avoid aggressive treatments, elect more home-based hospice care, and choose to avoid hospital-based procedures of treatments. [1,2] This may coincide with a shift of management and treatment leading to outpatient-based care, and with the development of medications that can be administered at home. [3,5] In addition, hospital-at-home as an alternative approach to traditional care-in-hospital is growing more common and may be beneficial for patients with cancer and dementia. [4] Together, they suggest a potential increase in healthcare utilization in settings other than hospitals, such as outpatient, ED, long-term care facilities, and throughout the community. To meet this potential increasing demand, resources and support for these non-inpatient healthcare delivery settings and for primary care physicians and family caregivers should be strengthened.

Meanwhile, improved interdisciplinary dementia and cancer care coupled with increased awareness of dementia, palliative care, and better support programs for patients and caregivers may also have helped to reduce unnecessary hospitalizations. [3] For example, studies have found that improved management among dementia patients reduced some unnecessary hospitalizations. [9] A steady decrease in cancer-related hospital admissions was also noted in some studies, particularly for colorectal cancer. [10] However, existing studies mainly focused on patients with either cancer or dementia, and investigations focused on patients with comorbid cancer, either overall or by cancer types, and dementia are lacking.

Our results also show that the time trend of hospitalization rates among Medicare FFS patients with the co-presence of a major cancer and dementia differed by cancer types. The increasing hospitalization rate among patients with lung cancer and dementia might in part be related to the adoption of lung cancer screening reimbursement by Medicare in 2015, which may have increased incidence diagnoses and subsequent hospitalizations of lung cancer treatment. The decreasing hospitalization rate among patients with colorectal cancer and dementia may in part be due to the early adoption of colorectal cancer screening. However, for breast and prostate cancers, which have had well-established cancer screening guidelines since 2002, we found a stable hospitalization trend. Future studies on patients with dementia and different cancer types are warranted.

The main limitation of the study includes the reliance on diagnosis codes for billing purposes, which may be misclassified or underreported, and on data from FFS Medicare beneficiaries, which may not be representative of older adults with other insurance types, such as Medicare Advantage. We also lacked detailed information about the sequence of disease onset and progression, cancer clinical presentation, and access to palliative care, which could affect hospital admissions and should be further studied. In addition, due to the heterogeneity of treatment modalities (e.g., surgery types) across cancer types, hospitalization trends for patients with a specific cancer type and comorbid dementia warrant in-depth investigation.

We found a stable trend of hospital admissions among Medicare FFS beneficiaries who had a co-presence of a major cancer and dementia from 2013 to 2018, which shows promise in reducing the healthcare resource use and costs associated with cancer and dementia related hospital admissions. The findings underscore the importance of strengthening healthcare resources beyond traditional inpatient care in order to meet the needs of this growing population. Suggested measures include helping primary care providers stay current on new developments in diagnosis and care for patients with both cancer and dementia, increasing support for caregivers, and facilitating the adoption of alternative cancer and dementia care models (e.g., home-based programs). The findings also call for continued monitoring of this trend, and in-depth investigations into its underlying causes.

Supplementary Material

Appendix A. Supplementary data

Supplementary data to this article can be found online at https://doi.org/10.1016/j.jgo.2022.04.012.