Disability-adjusted life year

Disability-adjusted life years (DALYs) are a way of measuring the effects of diseases. They are calculated as the number of years lost due to ill-health, disability, or early death. The measure was developed in the 1990s as a way of comparing the overall health and life expectancy of different countries.

Disability-adjusted life years lost per 100,000 inhabitants in 2004:

  No data

  Fewer than 9,250

  9,250–16,000

  16,000–22,750

  22,750–29,500

  29,500–36,250

  36,250–43,000

  43,000–49,750

  49,750–56,500

  56,500–63,250

  63,250–70,000

  70,000–80,000

  More than 80,000

DALYs are used in the field of public health and health impact assessment . They include the potential years of life lost due to premature death and years of 'healthy' life lost by virtue of being in states of poor health or disability. In so doing, mortality and morbidity are combined into a single figure.

Calculation

adjusted life year

Disability-adjusted life years are related to the quality-adjusted life year (QALY) measure; however, QALYs only measure the benefit with and without medical intervention and therefore do not measure the total burden. Also, QALYs tend to be an individual measure and not a measure of the whole population.

The most appropriate measure of the effects of chronic illness is time, both time lost due to premature death and time spent disabled by disease. One DALY, therefore, is equal to one year of healthy life lost.

How much a medical condition affects a person is called the disability weight (DW). This is determined by disease or disability and does not vary with age. Tables have been created of thousands of diseases and disabilities, ranging from Alzheimer's disease to loss of finger, with the disability weight meant to indicate the level of disability that results from the specific condition.

Examples of disability weight

Condition	DW 2004	DW 2010
Alzheimer's and other dementias	0.666	0.666
Blindness	0.594	0.195
Schizophrenia	0.528	0.576
AIDS	0.505	0.547
Burns 20%–60% of body	0.441	0.438
Fractured femur	0.372	0.308
Moderate depression episode	0.350	0.406
Amputation of foot	0.300	0.021–0.1674
Deafness	0.229	0.167–0.281
Infertility	0.180	0.026–0.056
Amputation of finger	0.102	0.030
Lower back pain	0.061	0.0322–0.0374

Examples of the disability weight are shown. Some of these are "short term", and the long-term weights may be different.