Cohort Disability Adjusted Life Years

The Cohort Disability Adjusted Life Years (C-DALYs) differs from the Disability measurement in the specification of the discount function. Namely, the discount formula e^-r(x-a) (where x = age, a = onset of disease year, and r=discount rate),is replaced by e^-rx.

Cohort Disability Adjusted Life Years (C-DALYs) measure the losses due to mortality, injury and morbidity in a community. Unlike DALYs, C-DALYs follows a cohort approach where losses are discounted from the time of the occurrance of the disease(death).

Results: Calculating losses to society using the DALYs formula for a hypothetical disease with a .9 disability weight lasting three years gives a result of 3.37 DALYs lost for a 40 year old compared to a loss of 3.35 DALYs for a 12 year old. Using C-DALYs under the same conditions gives a loss of 1.18 C-DALYs for the 40 year old and 2.34 for the 12 year old. If age-weights are omitted, hence, only interest is considered, DALYs for both ages would be the same (2.28) while C-DALYs would be 0.86 for the 40 year old and 2.0 for the 12 year old. In fact, including only the discount rate would make DALYs the same regardless of age.

C-DALYs and DALYs were calculated for Orange County, California to determine which diseases/conditions represented the highest burden. The following conditions, listed in order of importance, were found to have the highest burden in Orange County: Unipolar Major Depression, Osteoarthritis, Alcohol Use, Asthma, Bipolar Disorder, Drug Use. In comparison, Ischemic Heart Disease, Alzheimer, Unipolar Major Depression, and Cerebrovascular Disease were ranked the highest using DALYs. These same diseases were ranked 11, 10, 1, 16 respectively using C-DALYs.

In conclusion, C-DALYs calculate losses that are more consistent with Public Health objectives of prioritizing interventions to diminish premature mortality. The use of C-DALYs alters the ranking of diseases causing the most burden in Orange County when compared to DALYs.