Slide 1

Trends in Unintentional Injury Mortality among American Indians and Alaska Natives, Washington, 1990-2009

Megan Hoopes, MPH

Jenine Dankovchik, BSc
Elizabeth Knaster, MPH
David L. Nordstrom, PhD

Logo Northwest Portland Area Indian Health Board, Indian Leadership for Indian Health

Logo Urban Indian Health Institute, a Division of the Seattle Indian Health Board

Presented at:
2012 Annual APHA conference
San Francisco, October 2012

Slide 2

Background

Slide 3

Excess mortality among AI/ANs

• After declining in 1900s, AI/AN death rates rose in mid-1980s
• AI/AN life span 6 years below U.S. average
• Large racial disparities in injury deaths
• Injury prevention has become a public health priority area for Indian Country

Slide 4

AI/AN race often misclassified on death certificates

• Race not always based on self-report or next-of-kin report
• Net result: morbidity and mortality measures are underestimated for AI/AN
• One approach: Linkage between Indian patient registration data and disease registries

Slide 5

Improving Data & Enhancing Access (IDEA-NW)

• Project goals: Reduce misclassification of AI/AN race in surveillance systems; disseminate health data to NW tribes
• Linkages between Indian patient registration and various disease registries

Map showing where numerous Portland area tribes reside, the largest being Colville and Yakama Nation in Washington, Warm Springs in Oregon, and Coeur d'Alene, Nez Perce, and Shoshones in Idaho.

Slide 6

Methods

Slide 7

Data Sources and Linkage

• Washington death certificates, 1990-2009
• Northwest Tribal Registry
  • AI/AN registered at IHS/tribal clinics in the NW
  • Augmented with data from urban clinics
  • All records are known AI/AN
• Probabilistic linkage
  • Link Plus software
  • Names, birthdates, SSN, etc. are compared
  • Each pair given a score indicating likelihood of a match, "gray area" matches reviewed by hand

Slide 8

Analysis

• Cause of Death defined using ICD-9/10 only underlying cause of death
• AI/AN in analysis = AI/AN on death certificate and/or matched Tribal Registry
  • White race selected for comparison
  • Used bridged-race field
    • Race collection changed from single to multiple-mention during study period

Slide 9

Analysis

• Rates age-adjusted, per 100,000 population, 3-year rolling averages
• Trends: linear regression, p<.05
  • Annual percent change (APC)
    APC = (e^b₁-1) x100
• NCHS bridged-race population estimates used as population denominators

Slide 10

Results

Slide 11

Linkage increased ascertainment of AI/AN deaths by 12%

	Before linkage	After linkage
AI/AN Deaths	10,870	12,212
White Deaths	795,675	794,409

Slide 12

Washington AI/ANs died at younger ages (1990-2009)

	AI/AN	White	Difference
Mean age at death	57.7	73.6	15.9 years

Slide 13

Unintentional injury mortality rates over two times higher for AI/AN

Bar chart. Age adjusted rate per 100,000 for unintentional injury for Washington 1990 to 2009. All: A I A N 80.4, white 34.6. Male: A I A N 105.0, white 48.0. Female: A I A N 57.5, white 22.4.

Slide 14

Motor vehicle crashes and poisoning cause majority of injury deaths

Bar chart. Percentage of unintentional injury deaths by leading cause for Washington for 1990 to 2009. Motor vehicle crash, A I A N 47, white 38. Poisoning A I A N 21, white 17. Drowning A I A N 7, white 4. Falls A I A N 6, white 22.

Slide 15

Injury Trends

Slide 16

Unintentional injury mortality increased, AI/AN rates consistently higher than whites

Line chart. Age adjusted rate per 100,000 for unintentional injury mortality in Washington for 1990 to 2009. Line for A I A N starts at about 70 in 1990 to 1992 and jumps moderately above and below best fit line as it trends upward, ending at about 90 in 2007 to 2009. The line for A I A N is labeled A P C = positive 1.7 %.The line for whites trends smoothly upward along the best fit line from about 30 in 1990 to1992 to about 40 in 2007 to 2009. The line for white is labeled A P C = positive 1.4 %.

Slide 17

AI/AN MVC mortality rates consistently higher than whites, gap growing

Line chart. Age adjusted rate per 100,000 for motor vehicle crash mortality by race for Washington for 1990 to 2009. Line for A I A N starts at about 33 in 1990 to 1992 and moves moderately above and below the best fit line as it trends downward, ending at about 30 in 2007 to 2009. The line for whites trends smoothly downward along the best fit line from about 14 in 1990 to 1992 to about 9 in 2007 to2009. The line for whites is labeled A P C = negative 2.6%.

Slide 18

From 1994 onward, AI/AN unintentional drug poisoning rates higher than whites and increasing faster

Line chart. Age adjusted rate per 100,000 for unintentional drug poisoning mortality for Washington for 1990 to 2009. Line for A I A N starts at about 3 in 1990 to 1992 and moves moderately above and below the best fit line as it trends upward, ending at about 30 in 2007 to 2009. A P C = positive 14.6%. The line for whites trends smoothly upward close to the best fit line from about 3 in 1990 to 1992 to about 11 in 2007 to 2009. A P C = positive 10.7%.

Slide 19

Fall mortality rates similar to whites and increased marginally

Line chart. Age adjusted rate per 100,000 for unintentional falls mortality for Washington for 1990 to 2009. Line for A I A N starts at about 13 in 1990 to 1992, dips to 4 in 1994 to1996, then moves upward in a jumpy manner, ending at about 14 in 2007 to 2009. The line for whites trends moderately smoothly upward, moving above and below the best fit line, ending at about 11 in 2007 to 2009. A P C = positive 3.2%.

Slide 20

Drowning deaths decreased for both races, not significantly for AI/AN

Line chart. Age adjusted rate per 100,000 for unintentional drowning mortality for Washington for 1990 to 2009. Line for A I A N starts at about 6 in 1990 to 1992 and moves moderately above and below the best fit line as it trends downward, ending at about 4.5 in 2007 to 2009. The line for whites starts at about 1.5, trends smoothly downward close to the best fit line, ending at about 1 in 2007 to 2009. A P C = negative 1.3%.

Slide 21

Conclusions and Next Steps

Slide 22

Many disparities exist in mortality for Washington AI/ANs

• AI/ANs in Washington are dying much younger than whites
• Higher rates of mortality due to MVC, drug overdose
• Improvements in injury mortality experienced by whites have not always occurred for AI/ANs
• Correct racial classification is important factor in accurate mortality surveillance0
  • Linkage can help address misclassification

Slide 23

Challenges & next steps

• Tribal Registry under-represents urban AI/AN and those with private insurance
  • Captures 75-80% of AI/AN population
• Even with combined data years, small numbers make AI/AN rates unstable
• Death certificate data does not answer the "why" questions
  • Other data sources help with behavioral, environmental factors

Slide 24

Thank You

Acknowledgements

The Tribes of Washington — patients and their families
Victoria Warren-Mears, PhD (P.I.)
Washington DOH Center for Health Statistics
Urban Indian Health Institute, Seattle Indian Health Board
Grant #R01HS19972, Agency for Healthcare Research & Quality