Estimating the Effect of Hospital Admission on Health Care Outcomes and Spending Among Persons With Dementia : A Quasi-experimental Study

Topic: Risk, prevention and care in population studies

Background Because transitions in care settings can be confusing for persons with dementia (PWD), hospital admissions can negatively affect their physical and cognitive function. However, the effect of hospital admissions on patient outcomes and health care spending remains largely unknown. Objective To estimate the effects of hospital admissions on health outcomes and health care spending among PWD. Design Quasi-experimental instrumental variable method, using emergency physicians' admission propensity as the instrument. Setting United States. Patients Medicare fee-for-service beneficiaries aged 66 years or older with dementia who visited an emergency department (ED) in 2017 to 2019. Measurements Death, inpatient days (excluding the index hospital admission), and health care spending (excluding the index ED visit and hospital admission) within 30 and 90 days of ED visits. Results Among 872 085 ED visits (62.9% women; mean age, 83.1 years) included in the analysis, 482 208 (55.3%) resulted in hospital admission. There was no evidence that hospital admission was associated with 30-day mortality rate (adjusted risk difference, -2.6 percentage points [pp] [95% CI, -5.2 to 0.1 pp]) or inpatient days (adjusted difference, 0.1 days [CI, -0.2 to 0.5 days]). Hospital admission was associated with higher 30-day health care spending (adjusted difference, $2547 [CI, $1390 to $3703]). Patterns were similar for 90-day outcomes. Limitation Residual confounding. Conclusion Among Medicare beneficiaries with dementia who visited an ED, there was no evidence that hospital admission was associated with mortality rates. Under conventional statistical criteria, an effect of hospital admissions between a 5.2-pp decrease and a 0.1-pp increase in 30-day mortality rates was highly compatible with the data. On the contrary, hospital admission was associated with higher health care spending. Primary funding source None.

Key findings

• Results Among 872 085 ED visits (62.9% women; mean age, 83.1 years) included in the analysis, 482 208 (55.3%) resulted in hospital admission.
• There was no evidence that hospital admission was associated with 30-day mortality rate (adjusted risk difference, -2.6 percentage points [pp] [95% CI, -5.2 to 0.1 pp]) or inpatient days (adjusted difference, 0.1 days [CI, -0.2 to 0.5 days]).
• Hospital admission was associated with higher 30-day health care spending (adjusted difference, $2547 [CI, $1390 to $3703]).
• Conclusion Among Medicare beneficiaries with dementia who visited an ED, there was no evidence that hospital admission was associated with mortality rates.
• On the contrary, hospital admission was associated with higher health care spending.

Why it matters

In this analysis of Medicare beneficiaries with dementia who visited an emergency department, hospital admission was not linked to 30-day mortality or more inpatient days. Admission was linked to higher 30-day health care spending, so the findings concern costs and outcomes of hospital care rather than preventing or treating dementia.

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Study details

• Study designcohort
• Participants872,085
• Effect sizeHospital admission vs discharge: 30-day mortality adjusted risk difference -2.6 pp (95% CI -5.2 to 0.1); 30-day spending +2,547 USD (95% CI 1,390-3,703)
• Evidence strengthModerate

Limitations

Instrumental-variable estimates apply to marginal admissions, not to clearly necessary ones; residual confounding possible; US fee-for-service Medicare only.

Read the original

• DOI: 10.7326/ANNALS-25-03725
• PubMed: 42258826
• Original source →

May need a subscription Unpaywall and Europe PMC found no free copy of the full text (checked 10 Oct 2026), so the publisher may charge for it. The PubMed abstract is free.

@article{ikesu2026-42258826,
  author  = {Ikesu, Ryo and Mayeda, Elizabeth Rose and McGarry, Kathleen and Nianogo, Roch A and Ramirez, Christina M and Tsugawa, Yusuke},
  title   = {{Estimating the Effect of Hospital Admission on Health Care Outcomes and Spending Among Persons With Dementia : A Quasi-experimental Study}},
  journal = {Annals of internal medicine},
  year    = {2026},
  doi     = {10.7326/ANNALS-25-03725},
  pmid    = {42258826},
  url     = {https://doi.org/10.7326/ANNALS-25-03725}
}

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