The International Classification of Impairments, Disabilities and Handicaps, published by the World Health Organization, defines “impairment” as:

Any loss or abnormality of psychological, physio­logical, or anatomical structure or function

“Disability” is defined as:

Any restriction or lack (resulting from an impairment) of ability to perform an activity in the manner or within the range considered normal for a human being.

“Handicap” is defined as:

A disadvantage for a given individual, resulting from impairment or a disability, that limits or prevents the fulfillment of a role that is normal (depending on age, sex, social, and cultural factors) for that individual.

Each of these definitions can describe the reduction in quality of life patients with COPD suffer, as the disease progresses from mild to severe.

HRQOL refers to 3 aspects: physical, psychological, and social. Each of these is unique to the individual. It can be measured by an objective assessment of functioning or health status and the patient’s subjective perceptions of his or her optimal health.

These 3 aspects can be further broken down into factors most important to patients:

  • activities of daily living
  • social functioning (eg, relationships, work)
  • psychological functioning (eg, depression)
  • ability to participate in activities with enjoyment (eg, recreation, hobbies)