title: The Relative Impacts of Disease on Health Status and Capability Wellbeing: A Multi-Country Study.
abstract: BACKGROUND
  Evaluations of the impact of interventions for resource allocation purposes commonly focus on health status. There is, however, also concern about broader impacts on wellbeing and, increasingly, on a person's capability. This study aims to compare the impact on health status and capability of seven major health conditions, and highlight differences in treatment priorities when outcomes are measured by capability as opposed to health status.
  
  
  METHODS
  The study was a cross-sectional four country survey (n = 6650) of eight population groups: seven disease groups with: arthritis, asthma, cancer, depression, diabetes, hearing loss, and heart disease and one health population 'comparator' group. Two simple self-complete questionnaires were used to measure health status (EQ-5D-5L) and capability (ICECAP-A). Individuals were classified by illness severity using condition-specific questionnaires. Effect sizes were used to estimate: (i) the difference in health status and capability for those with conditions, relative to a healthy population; and (ii) the impact of the severity of the condition on health status and capability within each disease group.
  
  
  RESULTS
  5248 individuals were included in the analysis. Individuals with depression have the greatest mean reduction in both health (effect size, 1.26) and capability (1.22) compared to the healthy population. The effect sizes for capability for depression are much greater than for all other conditions, which is not the case for health. For example, the arthritis group effect size for health (1.24) is also high and similar to that of depression, whereas for the same arthritis group, the effect size for capability is much lower than that for depression (0.55). In terms of severity within disease groups, individuals categorised as 'mild' have similar capability levels to the healthy population (effect sizes <0.2, excluding depression) but lower health status than the healthy population (≥0.4).
  
  
  CONCLUSIONS
  Significant differences exist in the relative effect sizes across diseases when measured by health status and capability. In terms of treating morbidity, a shift in focus from health gain to capability gain would increase funding priorities for patients with depression specifically and severe illnesses more generally.
authors.affiliation: Health Economics Unit, Institute of Applied Health Research, University of Birmingham, Birmingham, United Kingdom.
authors.forename: Paul Mark
authors.initials: PM
authors.lastname: Mitchell
authors.affiliation: Health Economics Unit, Institute of Applied Health Research, University of Birmingham, Birmingham, United Kingdom.
authors.forename: Hareth
authors.initials: H
authors.lastname: Al-Janabi
authors.affiliation: Centre for Health Economics, Monash University, Melbourne, Australia.
authors.forename: Jeff
authors.initials: J
authors.lastname: Richardson
authors.affiliation: Centre for Health Economics, Monash University, Melbourne, Australia.
authors.forename: Angelo
authors.initials: A
authors.lastname: Iezzi
authors.affiliation: School of Social and Community Medicine, University of Bristol, Bristol, United Kingdom.
authors.forename: Joanna
authors.initials: J
authors.lastname: Coast
mesh_terms: D000208:Acute Disease / Q000534:rehabilitation*; D000293:Adolescent; D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D005260:Female; D006305:Health Status Indicators; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011788:Quality of Life; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires; D055815:Young Adult