Mohammad KA Basra; Muhammad Shahrukh


Expert Rev Pharmacoeconomics Outcomes Res. 2009;9(3):271-283. 

In This Article

Health, Impairment, Disability & Handicap

In 1948, the WHO defined health as[11]:

"not merely the absence of disease but complete physical, mental and social well-being"

In the light of this universal definition, consequences of non-fatal chronic diseases on human life can be classified (International Classification of Impairments, Disabilities, and Handicaps [ICIDH]) into three closely related categories, also defined by the WHO[12]:

  • 'Impairment' refers to loss of an anatomic structure or a physiological or psychological function due to a disease;

  • Disability is any restriction on normal performance of an activity due to impairment;

  • Handicap describes the consequences of disability for the patient. In other words, it is the disadvantage in fulfillment of a role resulting from impairment and disability. However, since handicap represents deviation of the person's status from that of the social group to which he belongs, it is more of a social problem than a personal one. Therefore, handicap reflects the impact of disease on society, rather than on the individual.[13]

In the context of dermatology, these three terms can be illustrated by the following examples. The thickening and scaling of the palms and soles due to keratoderma is the impairment, while disability from contact dermatitis may result in loss of ability to use one's hands because of severe inflammation and the loss of this hand function from contact dermatitis may render a hairdresser or cook unable to carry on with her/his occupation, which is handicap.

In 1992, it was realized that that the ICIDH had some conceptual shortcomings that should be addressed. Some of the major shortcomings included overlap between the dimensions of Impairment and Disability and between the dimensions of Disability and Handicap, a lack of clarity about the causal and temporal relationships between these three dimensions, and insufficient attention to the role of the environment.[14] To address these shortcomings in the ICIDH, a new classification based on the 'model of functioning and activity' has been developed, the ICIDH-2.[15] According to the ICIDH-2, information is organized into three dimensions: body level, individual level and societal level. These dimensions are named as:

  • 'Body functions and structure': significant deviations or loss of which are described as impairments;

  • 'Activities': describes the performance of person-level tasks, while activity limitations are classified to the extent that the individual has difficulty performing the activity;

  • 'Participation': defined as an individual's involvement in life situations in relation to body functions and structure, health conditions, activities and contextual factors.[15] In this definition, a key term is involvement, which means inclusion of the individual in life activities in the context of where they live.[14] The restriction of participation in life activities by external factors, such as social rules, is referred to as participation restriction, which is usually assessed by comparing the participation in activities of individuals with and without disabilities in that particular society.


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