Conceptual Foundations for Health Measurements

WHO Classifications International Classification of Diseases (ICD) Etiological framework Diagnosis of health condition Disease process, signs & symptoms International Classification of Impairments, Disabilities & Handicaps (ICIDH) How people live; body functions Activities & participation

Disability and Handicap

Conceptions of Disability “a disability is any restriction or lack of ability (resulting from an impairment) to perform an activity in the manner or within the range considered normal for a human being” (WHO ICIDH, 1980.)

ICIDH - 1 Impairment Disability Handicap Body Society (N.b. dotted arrows indicate that one stage may, but need not, influence the next)

ICIDH Classification of health domains Framework to study health and health-related outcomes Covers non fatal outcomes

Issues in the Definition Defining disability in terms of activity limitations is neat, but what activities? What level of limitation should be used? Same expectations for everyone, or relative to age, sex, etc.? Threshold: does not perform an activity, versus cannot perform it? Doesn’t but could??

ICIDH - 2 Appeared March, 2001 Conceptual changes: From consequences of disease (1980) to components of health (2000) Uses more positive language (‘activity’ & ‘participation’ instead of ‘disability’ & ‘handicap’) Broadens concept of disability More on environmental factors in which the person lives

ICIDH - 2 Health Condition (disorder / disease) Body Functions & structures Activities Participation BODY Structure & Function PERSON Activities SOCIETY Participation impairment limitation restriction

Body Functions Mental functions Sensory Voice & speech CVD, hematological, etc. Digestive, metabolic & endocrine Genitourinary Neuro-musculoskeletal Skin

Activities & Participation Learning Communication Movement Self-care Domestic activities Interpersonal Major life activities Community Exchanging information Communicating Mobility Personal maintenance Home life Social relationships Work & employment Social & civic life

Health-Related Quality of Life

Quality of Life Quality of life is subjective & value-specific Invented in the USA; ¿not universal? Definition will at least vary across cultures (naïve enthusiasm for QoL) Handicap reflects impairment + environment, so measures may perform differently in different environments

Quality of Life (from a consumer’s perspective) Quality of life is… Having the important people in your life see your strengths and talents A good night’s sleep Validation of worth and affirmation of experience Having control of your own life Taking control of your condition Life free from stigma Having a ‘real’ job Having a purpose Being free to come and go Carne, B. A consumer perspective. Can J Community Mental Health 1998, Suppl 3: 21.

The Deceptive Simplicity of HRQOL… Health-Related Quality of Life Or Quantity? (How would we we measure quality?) Definition? What model? (Caused by Associated with? or ?) Of life or Living?

Mapping Physical Measures onto Quality of Life Clinical / Physical Markers Disease-Specific Dysfunction Health-Related Quality of Life Overall Quality of Life Source: SH Kaplan et al. Medical Care, 2000