U.S. Military Burden of Disease Study: Disability Weights Using a Web-based Survey Among Military Service Members

Current metrics assessing medical readiness of the force are incomplete and may provide a biased assessment. Disability-adjusted life year (DALY) is a metric that provides a method to equate illnesses that would otherwise be incomparable (e.g., disease versus trauma injury). DALYs are calculated using disability weights, which reflect the severity of the illness. Currently utilized general population disability weights may not apply to service members because of the specific demands of military service. Our objective was (1) to estimate disability weights for U.S. service members and (2) to determine if the newly developed disability weights for service members were comparable to disability weights developed for the general population in the Global Burden of Disease (GBD) 2010 study.

We used web-based surveys to assess disability weights among a representative sample of U.S. service members using the GBD 2010 disability weights measurement approach. Cardinal values from paired comparison responses were estimated through probit regression. To locate cardinal values on the 0-to-1 disability weight scale, we used non-parametric regression. Eligible participants were active, reserve, and National Guard service members identified through simple random sampling of the Defense Manpower Data Center. The differences between the 220 disability weights included in both the GBD survey and the current survey were compared by the Wilcoxon signed-rank test and Spearman's correlation.

In total, 165 respondents participated in our survey. Disability weights in the U.S. service member study and GBD study had a strong positive correlation (Spearman's rho = 0.883), and the median disability weight of all 220 health states did not differ significantly (P = .169).

Determining U.S. military-specific disability weights are similar to the GBD disability weights promotes a broader understanding of the applicability of global health metrics to military populations. The strong correlation and lack of significant difference suggest that general population disability weights can be utilized to approximate the burden of disease within the military. This knowledge is an essential component of informed policymaking to improve military medical readiness.