BACKGROUND: Disability free life expectancy (DFLE) calculated at the census tract level is a single measure that describes how long populations can be expected to live healthy lives. Implications of using DFLE are identification of areas with health inequities, evaluation of environmental and health systems interventions, and community-clinical linkages. DFLE is a flexible metric because any disability can be used to fit the programmatic goals as long as the disability can be calculated at a small area for multiple age groups.
METHODS: DFLE, using the Chiang II and Sullivan method, is not difficult to calculate. DFLE calculation for Virginia census tracts involved adding the estimates of the proportion of individuals with disabilities by tract and age group to the abridged life table estimates of mortality and population used for creating life expectancy estimates. The life table with the proportion of disabled individuals was the input for the analysis using the Chiang II methodology with Silcock’s adjustment for calculation of LE and Sullivan’s methods for DFLE. The disabled population proportion was defined for this study as answering yes to any one of the six Census American Community Survey disability questions (2009-2013 agg.). Significant consideration must be given to disability chosen, small area analysis problems, and how to share the analysis for best impact. At the tract level, data censorship needs to be considered when unusual population distributions are encountered. Minimum population size requirements must be met to reduce large standard errors. Small areas that do not meet requirements can be combined with like neighbors. DFLE estimates were added to a multiple linear regression model with social determinants of health (SDH) as the explanatory variables. DFLE estimates were mapped using ArcGIS v10.2.2.
RESULTS: DFLE ranged from 37 to 86 with a median of 65 years. DFLE was significantly related to SDHs and most strongly with educational, affordability, and employment determinants. The lowest DFLE of 37 years was in a naval shipyard neighborhood and the highest were in areas with high income. Some areas could expect to live half of their life with a disability and other areas could expect only a few years of disability before death.
CONCLUSIONS: DFLE is a fundamental outcome measure to gauge healthy years of life. It can be used to model SDHs to identify prevailing relationships to target for meaningful change, health inequities, and winning strategies that improve well-being.