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  1. 1. Disability Adjusted Life Years (DALYs) and the Traffic-Related Burden of Disease in California DR MUHAMMAD TAUSEEF JAVEDMBBS.DPH.FCPS(CM)M.Phil(CM).Dip-Card DR MUHAMMAD TAUSEEF JAVED
  2. 2. Quick Outline• Background – Summary measures of health – Disability Adjusted Life Years (DALYs) – DALYs & the Global Burden of Disease study – Relevance for the Traffic Safety Center• Methodology• Results• Conclusions• Future Directions DR MUHAMMAD TAUSEEF JAVED
  3. 3. Measures of Population Health: Mortality and Morbidity Measures# deaths, death rate, # injured, # head injuries,# severe injuries, rate of injuries, # hospitalizations Summary MeasuresAggregate mortality and morbidity into asingle measure# years healthy life lost (DALYs, QALYs) DR MUHAMMAD TAUSEEF JAVED
  4. 4. Summary Measures of Population Health: Why use them?• Compare the health of one population with another• Analyze the benefits of health interventions for use in cost-effectiveness analysis• Identify and quantify overall health inequalities within populations• Informing debates on health policy• Monitor changes in the health of a given population• Attribute burden from risk factors DR MUHAMMAD TAUSEEF [WHO – Summary Measures of JAVED Population Health, 2002]
  5. 5. Disability Adjusted Life Years (DALYs)• Measures healthy time lost from specific diseases and injuries in a population• Comparable and additive across diseases Ex: Broken scapula = .5 DALYs lost Protein deficiency = 2 DALYs lost• Based on relatively accessible incidence data (ICD codes) DR MUHAMMAD TAUSEEF JAVED
  6. 6. DALY Calculation (the easiest way) Years lost to Years of lost life disability + (YLLs) (YLDs) Inputs Inputs • Duration of disease/injury• Life expectancy at age of death • Disability weight of disease/injury• Age at death • % long-term cases DR MUHAMMAD TAUSEEF JAVED
  7. 7. DALY Calculation: an example A Two-Car Collision 1 family dies 2 people injured– 10 year old girl – 45 y/o woman – SCI– 8 year old boy – 55 y/o man – fractured rib– 38 year old mother– 42 year old father YLLs from deaths YLDs from injuries– 70 year life expectancy - Duration (36 year LE) *– 73 year life expectancy Disability Wt (.725) = 26 YLDs– 46 year life expectancy - Duration (.115 years) * Disability– 33 year life expectancy Wt (.199) = 0.02 YLDs 222 YLLs + JAVED 26.02 YLDs DR MUHAMMAD TAUSEEF = 248.02 YLDs
  8. 8. DALY Calculations: Adjustments• Designed to allow tailoring to local social values and specific applications for the DALYs• Age-weighting – weights the life of a 21 year-old (for instance) more heavily than other ages according to societal preferences.• Discounting – commonly used in economic analyses, recommended for DALYs if using the outcome measure in such analyses• Caused much contention• DALYs can be calculated without such adjustments DR MUHAMMAD TAUSEEF JAVED
  9. 9. DALYs and the Global Burden of Disease• WHO/World Bank Global • Quick results Burden of Disease study – Ranked 9th in cause of outlined methodology for total DALYs in the DALYs world in 1990• First attempt at a – Still ranked 9th in 2000 comprehensive picture of estimates global health – Predicted to be ranked• Ranked diseases according 3rd in 2020 to the number of DALYs• Projected rankings to 2020 DR MUHAMMAD TAUSEEF JAVED
  10. 10. DALYs and the Traffic-Related Burden of Disease in California• DALYs as a measure of traffic-related outcomes in California – Different than that captured by mortality or injury alone?• Characterize the traffic-related burden of disease in more detail for age, gender, and ethnicity – By occupant, pedestrian, bicyclist, etc.• Construct a database of traffic-related DALYs for California for use in comparisons to global, regional, state, and city trends. DR MUHAMMAD TAUSEEF JAVED
  11. 11. Methods: Case Definitions• GBD case definition for injury: “One that leads immediately to death or that is non-fatal but severe enough to warrant hospital treatment.”• “Road Traffic Accidents” category based on the E-codes on hospital discharge – CDC and the GBD recommendations do not entirely coincide• Each injury type has a specified disability weight, duration, % long-term cases in the GBD DR MUHAMMAD TAUSEEF JAVED
  12. 12. Methods: DALY Calculation Data Sources Mortality Morbidity CA Vital Statistics OSHPD hospital discharge data EPIC database EPIC database+ Age- and sex- specific + Age- & sex-specific deaths listed by injuries by ethnicity and ethnicity and county county + Injury by E-code and+/- ICD-10 coding for nature of injury codes 1999 and later +/- ICD-9 coding -- Need individual level data DR MUHAMMAD TAUSEEF JAVED Coverage? --
  13. 13. Methods: DALY calculations YLLs and YLDs• Ethnicity, gender, age by External injury category (Motor vehicle Occupant, Pedestrian, Motorcyclist, or Bicyclist)• Using highest world life expectancy and 3% discount rate• YLL calculation• YLDs – calculated for each type of injury and body part injured by age, gender, and ethnicity Ex: Amputation of upper limb for 50-55 y/o Asian males = x YLDs DR MUHAMMAD TAUSEEF JAVED
  14. 14. Methods: DALY calculations Comparison Measures• Sum YLLs and YLDs for population = DALYs• Calculate the # of deaths and the # of injuries for same categories from same data• Test rank-order for DALYs, deaths, injuries, others?• Compare rates to global, regional, national, city (San Francisco, Los Angeles) DALY rates. DR MUHAMMAD TAUSEEF JAVED
  15. 15. Results?• Not much yet.• Gender and age DALY calculations by injury category is complete (as of yesterday)• YLLs by ethnicity are complete while YLDs are still being calculated DR MUHAMMAD TAUSEEF JAVED
  16. 16. Preliminary Results: Gender• Consistency of the distribution of total traffic- related burden between genders ~70% California DALYs – 71% male Regional DALYs – 70% male World DALYs – 70% male California deaths – 69% male California injuries – 62% male DR MUHAMMAD TAUSEEF JAVED
  17. 17. Preliminary Results: Ethnicity YLLs Death Death GBD YLL CDC YLL Rate per GBD CDC YLL Rate perFemales rates rates 100,000 Males YLL rates rates 100,000White 144 119 6 White 328 274 15Native American81 2 182 6 Native American 302 201 13Hispanic 168 146 5 Hispanic 482 392 14Black 143 123 8 Black 387 349 8Asian 117 95 5 Asian 231 212 9 Death GBD CDC YLL Rate per Totals YLL rates rates 100,000 White 472 393 10 Native American 583 383 10 Hispanic 650 537 10 Black 531 473 8 Asian 348 307 7 DR MUHAMMAD TAUSEEF JAVED
  18. 18. Conclusions thus far…• The epi data necessary for YLD calculation is limited. – Primary diagnosis may not be the most severe injury  underestimation• Traffic-related DALYs are largely composed of the YLL (deaths)• Future analyses will be more challenging with HIPPA system in place DR MUHAMMAD TAUSEEF JAVED
  19. 19. Future directions…• By how much can the burden be reduced? How low can we feasibly get it?• How much of the burden is attributable to lack of restraint-use? How much could we reduce the burden if we increase seatbelt use by 5%? Would we get more DALYs if we decrease alcohol-related burden by 5%? DR MUHAMMAD TAUSEEF JAVED