title: Association of living alone and hospitalization among community-dwelling elders with and without dementia.
abstract: BACKGROUND
  Older persons account for the majority of hospitalizations in the United States.1 Identifying risk factors for hospitalization among elders, especially potentially preventable hospitalization, may suggest opportunities to improve primary care. Certain factors-for example, living alone-may increase the risk for hospitalization, and their effect may be greater among persons with dementia and the old-old (aged 85+).
  
  
  OBJECTIVE
  To determine the association of living alone and risk for hospitalization, and see if the observed effect is greater among persons with dementia or the old-old.
  
  
  METHODS
  Retrospective longitudinal cohort study.
  
  
  METHODS
  2,636 participants in the Adult Changes in Thought (ACT) study, a longitudinal cohort study of dementia incidence. Participants were adults aged 65+ enrolled in an integrated health care system who completed biennial follow-up visits to assess for dementia and living situation.
  
  
  METHODS
  Hospitalization for all causes and for ambulatory care sensitive conditions (ACSCs) were identified using automated data.
  
  
  RESULTS
  At baseline, the mean age of participants was 75.5 years, 59 % were female and 36 % lived alone. Follow-up time averaged 8.4 years (SD 3.5), yielding 10,431 approximately 2-year periods for analysis. Living alone was positively associated with being aged 85+, female, and having lower reported social support and better physical function, and negatively associated with having dementia. In a regression model adjusted for age, sex, comorbidity burden, physical function and length of follow-up, living alone was not associated with all-cause (OR = 0.93; 95 % CI 0.84, 1.03) or ambulatory care sensitive condition (ACSC) hospitalization (OR = 0.88; 95 % CI 0.73, 1.07). Among participants aged 85+, living alone was associated with a lower risk for all-cause (OR = 0.76; 95 % CI 0.61, 0.94), but not ACSC hospitalization. Dementia did not modify any observed associations.
  
  
  CONCLUSIONS
  Living alone in later life did not increase hospitalization risk, and in this population may be a marker of healthy aging in the old-old.
authors.affiliation: Department of Health Services, School of Public Health, University of Washington, Box 357230, Seattle, WA, 98195, USA, ennis.steph@gmail.com.
authors.forename: Stephanie K
authors.initials: SK
authors.lastname: Ennis
authors.forename: Eric B
authors.initials: EB
authors.lastname: Larson
authors.forename: Louis
authors.initials: L
authors.lastname: Grothaus
authors.forename: Christian D
authors.initials: CD
authors.lastname: Helfrich
authors.forename: Steven
authors.initials: S
authors.lastname: Balch
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Phelan
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003704:Dementia / Q000453:epidemiology*; D005260:Female; D005500:Follow-Up Studies; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D012111:Residence Characteristics / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D012307:Risk Factors; D012959:Socioeconomic Factors; D014481:United States / Q000453:epidemiology