title: Influence of municipality-level mean income on access to aortic valve surgery: a cross-sectional observational study under Japan's universal health-care coverage.
abstract: BACKGROUND
  Universal health-care coverage has attracted the interest of policy makers as a way of achieving health equity. However, previous reports have shown that despite universal coverage, socioeconomic disparity persists in access to high-tech invasive care, such as cardiac treatment. In this study, we aimed to investigate the association between socioeconomic status and care of aortic stenosis in the context of Japan's health-care system, which is mainly publicly funded.
  
  
  METHODS
  We chose aortic stenosis in older people as a target because such patients are likely to be affected by socioeconomic disparity. Using a large Japanese claim-based inpatient database, we identified 12,893 isolated aortic stenosis patients aged over 65 years who were hospitalized between July 2010 and March 2012. Municipality socioeconomic status was represented by the mean household income of the patients' residential municipality, categorized into quartiles. The likelihood of undergoing aortic valve surgery and in-hospital mortality was regressed against socioeconomic status level with adjustments for hospital volume, regional number of cardiac surgeons per 1 million population, and patients' clinical status.
  
  
  RESULTS
  We found no significant differences between the highest and lowest quartile groups in surgical indication (odds ratio, 0.84; 95% confidence interval, 0.69-1.03) or in-hospital mortality (1.00; 0.68-1.48). Hospital volume was significantly associated with lower postoperative mortality (odds ratio of the highest volume tertile to the lowest, 0.49; 0.34-0.71).
  
  
  CONCLUSIONS
  Under Japan's current universal health-care coverage, municipality socioeconomic status did not appear to have a systematic relationship with either treatment decision for surgical intervention or postoperative survival following aortic valve surgery among older patients. Our results imply that universal health-care coverage with high publicly funded coverage offers equal access to high-tech cardiovascular care.
authors.affiliation: Department of Cardiovascular Medicine, The University of Tokyo, Tokyo, Japan.
authors.forename: Seitetsu L
authors.initials: SL
authors.lastname: Lee
authors.affiliation: Department of Health and Social Behavior, The University of Tokyo, Tokyo, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Hashimoto
authors.affiliation: Department of Clinical Informatics, Jichi Medical University, Tochigi, Japan.
authors.forename: Takahide
authors.initials: T
authors.lastname: Kohro
authors.affiliation: Department of Clinical Data Management and Research, Clinical Research Center, National Hospital Organization Headquarters, Tokyo, Japan.
authors.forename: Hiromasa
authors.initials: H
authors.lastname: Horiguchi
authors.affiliation: Department of Clinical Epidemiology and Systems, The University of Tokyo, Tokyo, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Koide
authors.affiliation: Department of Cardiovascular Medicine, The University of Tokyo, Tokyo, Japan.
authors.forename: Issei
authors.initials: I
authors.lastname: Komuro
authors.affiliation: Department of Health Policy and Informatics, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Kiyohide
authors.initials: K
authors.lastname: Fushimi
authors.affiliation: Clinical Research Support Center, The University of Tokyo, Tokyo, Japan.
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Yamazaki
authors.affiliation: Department of Clinical Epidemiology and Health Economics, The University of Tokyo, Tokyo, Japan.
authors.forename: Hideo
authors.initials: H
authors.lastname: Yasunaga
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001021:Aortic Valve / Q000601:surgery*; D001024:Aortic Valve Stenosis / Q000601:surgery*; D002947:Cities; D003695:Delivery of Health Care / Q000191:economics*; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D007182:Income; D007564:Japan; D012923:Social Class; D019472:Universal Health Insurance / Q000191:economics*; D014505:Urban Population