Growth in Dementia-Associated Hospitalizations Among the Oldest Old in the United States: Implications for Ethical Health Services Planning

As the world population ages, an epidemic of neurologic diseases, such as Alzheimer-type dementia and Parkinson disease, is predicted. The most rapid population growth has been observed in the 85 years and older group, and, while it currently represents less than 2% of the US population, by year 2050 it will exceed 4%.¹ Concurrent with this population growth, we have witnessed a vast expansion of health care utilization and expenditures, with the consequent close scrutiny and attempts to rein in this supply-driven juggernaut.

Hospitalization, though lifesaving under many circumstances, is a strong driver of health care spending.² Evidence indicates that at the nexus of extreme aging and advanced dementia, overutilization of health care does not result in improved quality of life, is often not consistent with patients' goals of care, and indeed may be harmful.^3-5 Thus appropriateness and desirability of aggressive care, such as acute care hospitalizations, for these patients may need to be re-examined.

We conducted this analysis to gain a better understanding of the current trends in dementia-associated hospitalizations among the 85 years and older population in the United States and its implications for future health care policy planning.

We obtained data on all hospitalizations involving a dementia diagnosis for the 85 years and older group between years 2000 and 2008 from the nationally representative Nationwide Inpatient Sample database, a part of the Agency for Healthcare Research and Quality Healthcare Costs and Utilization Project (dementia codes are listed in the eAppendix. The aggregate data used are publicly available.⁶ To arrive at the annual hospitalization incidence, we obtained censal and intercensal population estimates and projections from the US Census Bureau.¹ We projected the future volume of hospitalizations involving a dementia diagnosis in the 85 years and older group using 2 distinct methods. The first method did not allow for longitudinal growth of the dementia hospitalizations incidence (static). Meant to compute the absolute minimum level of the potential growth due only to underlying population shifts, the first method projected future volumes based on years 2000 and 2008 incidences. The second method (dynamic), in addition to taking into account the overall population growth, also considered the observed historic increase in the age-adjusted incidence of dementia hospitalizations between years 2000 and 2008. For this estimate, according to previously published methodology,⁷ we constructed a linear regression model based on the historic data and applied this calculation forward (eTables 1-3).

Between 2000 and 2008, although the 85 years and older population comprised less than 2% of the total US population, they represented more than 40% of all annual hospitalizations associated with dementia. The actual absolute volume growth from 700 000 to 1.2 million hospitalizations for the oldest old with a dementia diagnosis between 2000 and 2008 (Figure) equated to population incidence increase from 16 398 to 21 088 cases per 100 000 population. According to static projections, the estimated 2050 volume of dementia hospitalizations in the 85 years and older group may be between 3 and 4 million cases, while the dynamic model predicted a rise to over 7 million dementia-associated hospitalizations (Figure and eTable 3). This represents a 10-fold growth in the volume of these hospitalizations from the year 2000 baseline.

Even at its minimum, the absolute growth in hospitalizations involving a dementia diagnosis is alarming in that without planning, the growth in hospitalizations may well overwhelm a health care system already under strain. In addition, humanistic considerations dictate that this degree of aggressive care may be inappropriate for many patients with dementia. For example, it has been reported that patients with advanced-stage disease have a prognosis comparable to metastatic breast cancer or stage IV heart failure.⁸ Although our data are unable to convey the severity of the observed dementia diagnoses, a recent study noted that 18.7% of nursing home residents with advanced dementia were hospitalized near the end of life, even though the most frequently stated goal of care was comfort.⁸ For such patients, hospitalizations represent more of an intrusive burden than a desirable intervention. These data, in conjunction with the emerging evidence on potential futility and even harm of aggressive care,^3,5 emphasize the need for developing models of caring for elderly patients with advanced dementia, with the intention of building ethically congruent infrastructures for this predicted explosion of neurologic disease.

Correspondence: Dr Zilberberg, Department of Epidemiology, EviMed Research Group, LLC, PO Box 303, Goshen, MA 01032 (evimedgroup@gmail.com).

Author Contributions: Dr Zilberberg had full access to all the data and takes responsibility for the integrity of the data and the accuracy of the data analysis. Study concept and design: Zilberberg. Acquisition of data: Zilberberg. Analysis and interpretation of data: Zilberberg and Tjia. Drafting of the manuscript: Zilberberg. Critical revision of the manuscript for important intellectual content: Zilberberg and Tjia. Statistical analysis: Zilberberg.