title: Multimorbidity patterns of and use of health services by Swedish 85-year-olds: an exploratory study.
abstract: BACKGROUND
  As life expectancy continues to rise, more elderly are reaching advanced ages (≥80 years). The increasing prevalence of multimorbidity places additional demands on health-care resources for the elderly. Previous studies noted the impact of multimorbidity on the use of health services, but the effects of multimorbidity patterns on health-service use have not been well studied, especially for very old people. This study determines patterns of multimorbidity associated with emergency-room visits and hospitalization in an 85-year-old population.
  
  
  METHODS
  Health and living conditions were reported via postal questionnaire by 496 Linköping residents aged 85 years (189 men and 307 women). Diagnoses of morbidity were reviewed in patients' case reports, and the local health-care register provided information on the use of health services. Hierarchical cluster analysis was applied to evaluate patterns of multimorbidity with gender stratification. Factors associated with emergency-room visits and hospitalization were analyzed using logistic regression models.
  
  
  RESULTS
  Cluster analyses revealed five clusters: vascular, cardiopulmonary, cardiac (only for men), somatic-mental (only for men), mental disease (only for women), and three other clusters related to aging (one for men and two for women). Heart failure in men (OR = 2.4, 95% CI = 1-5.7) and women (OR = 3, 95% CI = 1.3-6.9) as a single morbidity explained more variance than morbidity clusters in models of emergency-room visits. Men's cardiac cluster (OR = 1.6; 95% CI = 1-2.7) and women's cardiopulmonary cluster (OR = 1.7, 95% CI = 1.2-2.4) were significantly associated with hospitalization. The combination of the cardiopulmonary cluster with the men's cardiac cluster (OR = 1.6, 95% CI = 1-2.4) and one of the women's aging clusters (OR = 0.5, 95% CI = 0.3-0.8) showed interaction effects on hospitalization.
  
  
  CONCLUSIONS
  In this 85-year-old population, patterns of cardiac and pulmonary conditions were better than a single morbidity in explaining hospitalization. Heart failure was superior to multimorbidity patterns in explaining emergency-room visits. A holistic approach to examining the patterns of multimorbidity and their relationships with the use of health services will contribute to both local health care policy and geriatric practice.
authors.affiliation: Department of Clinical and Experimental Medicine, Division of Geriatrics, Faculty of Health Sciences, Linköping University, 581 85 Linköping, Sweden. huanji.dong@liu.se.
authors.forename: Huan-Ji
authors.initials: HJ
authors.lastname: Dong
authors.forename: Ewa
authors.initials: E
authors.lastname: Wressle
authors.forename: Jan
authors.initials: J
authors.lastname: Marcusson
mesh_terms: D000369:Aged, 80 and over; D002318:Cardiovascular Diseases / Q000175:diagnosis / Q000453:epidemiology* / Q000628:therapy; D015897:Comorbidity; D004632:Emergency Medical Services / Q000706:statistics & numerical data*; D005260:Female; D006299:Health Services for the Aged / Q000706:statistics & numerical data*; D006760:Hospitalization / Q000639:trends*; D006801:Humans; D008171:Lung Diseases / Q000175:diagnosis / Q000453:epidemiology* / Q000628:therapy; D008297:Male; D011795:Surveys and Questionnaires; D013548:Sweden / Q000453:epidemiology