title: Absence of a Socioeconomic Gradient in Older Adults' Survival with Multiple Chronic Conditions.
abstract: BACKGROUND
  Individuals of low socioeconomic status experience a disproportionate burden of chronic conditions; however it is unclear whether chronic condition burden affects survival differently across socioeconomic strata.
  
  
  METHODS
  This retrospective cohort study used health administrative data from all residents of Ontario, Canada aged 65 to 105 with at least one of 16 chronic conditions on April 1, 2009 (n = 1,518,939). Chronic condition burden and unadjusted mortality were compared across neighborhood income quintiles. Multivariable Cox proportional hazards models were used to examine the effect of number of chronic conditions on two-year survival across income quintiles.
  
  
  RESULTS
  Prevalence of five or more chronic conditions was significantly higher among older adults in the poorest neighborhoods (18.2%) than the wealthiest (14.3%) (Standardized difference > 0·1). There was also a socioeconomic gradient in unadjusted mortality over two years: 10.1% of people in the poorest neighborhoods died compared with 7.6% of people in the wealthiest neighborhoods. In adjusted analyses, having more chronic conditions was associated with a statistically significant increase in hazard of death over two years, however the magnitude of this effect was comparable across income quintiles. Individuals in the poorest neighborhoods with four chronic conditions had 2.07 times higher hazard of death (95% CI: 1.97-2.19) than those with one chronic condition, but this was comparable to the hazard associated with four chronic conditions in the wealthiest neighborhoods (HR: 2.29, 95% CI: 2.16-2.43).
  
  
  CONCLUSIONS
  Among older adults with universal access to health care, the deleterious effect of increasing chronic condition burden on two-year hazard of death was consistent across neighborhood income quintiles once baseline differences in condition burden were accounted for. This may be partly attributable to equal access to, and utilization of, health care. Alternate explanations for these findings, including study limitations, are also discussed.
authors: Institute of Health Policy, Management and Evaluation, University of Toronto, 155 College Street, 4th Floor, Toronto, Ontario M5T 3M6, Canada.
authors: Natasha E
authors: NE
authors: Lane
authors: Institute for Clinical Evaluative Sciences, 2075 Bayview Avenue, Toronto, Ontario M4N 3M5, Canada; Schools of Pharmacy and Public Health & Health Systems, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1, Canada.
authors: Colleen J
authors: CJ
authors: Maxwell
authors: Institute of Health Policy, Management and Evaluation, University of Toronto, 155 College Street, 4th Floor, Toronto, Ontario M5T 3M6, Canada; Institute for Clinical Evaluative Sciences, 2075 Bayview Avenue, Toronto, Ontario M4N 3M5, Canada; Women's College Hospital, 790 Bay Street, Toronto, Ontario M5G 1N8, Canada; Department of Family Medicine, University of Alberta, 6-10 University Terrace, Edmonton, Alberta T6G 2T4, Canada.
authors: Andrea
authors: A
authors: Gruneir
authors: Institute of Health Policy, Management and Evaluation, University of Toronto, 155 College Street, 4th Floor, Toronto, Ontario M5T 3M6, Canada; Institute for Clinical Evaluative Sciences, 2075 Bayview Avenue, Toronto, Ontario M4N 3M5, Canada.
authors: Susan E
authors: SE
authors: Bronskill
authors: Institute of Health Policy, Management and Evaluation, University of Toronto, 155 College Street, 4th Floor, Toronto, Ontario M5T 3M6, Canada; Institute for Clinical Evaluative Sciences, 2075 Bayview Avenue, Toronto, Ontario M4N 3M5, Canada; Toronto Rehabilitation Institute, 550 University Avenue, Toronto, Ontario M5G 2A2, Canada.
authors: Walter P
authors: WP
authors: Wodchis
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002908:Chronic Disease / Q000453:epidemiology / Q000401:mortality*; D015897:Comorbidity; D005260:Female; D006297:Health Services Accessibility; D006801:Humans; D008297:Male; D009864:Ontario / Q000453:epidemiology; D016016:Proportional Hazards Models; D062486:Public Health Surveillance; D012111:Residence Characteristics; D012189:Retrospective Studies; D012923:Social Class; D012959:Socioeconomic Factors
keywords: Chronic disease; Comorbidity; Socioeconomic status; Survival analysis