Decomposition of disparities in life expectancy with applications to administrative health claims and registry data

Abstract

Research shows that geographic disparities in life expectancy between leading and lagging states are increasing over time while racial disparities between Black and White Americans have been going down. In the 65+ age strata morbidity is the most common cause of death, making differences in morbidity and associated adverse health-related outcomes between advantaged and disadvantaged groups an important aspect of disparities in life expectancy at age 65 (LE65). In this study, we used Pollard's decomposition to evaluate the disease-related contributions to disparities in LE65 for two types of data with distinctly differing structures: population/registry and administrative claims. To do so, we analyzed Pollard's integral, which is exact by construction, and developed exact analytic solutions for both types of data without the need for numerical integration. The solutions are broadly applicable and easily implemented. Applying these solutions, we found that the largest relative contributions to geographic disparities in LE65 were chronic lower respiratory diseases, circulatory diseases, and lung cancer; and, to racial disparities: arterial hypertension, diabetes mellitus, and cerebrovascular diseases. Overall, the increase in LE65 observed over 1998-2005 and 2010-2017 was primarily due to a reduction in the contributions of acute and chronic ischemic diseases; this was partially offset by increased contributions of diseases of the nervous system including dementia and Alzheimer's disease.

Keywords: Decomposition methods; Disparities; Life expectancy at 65; Medicare; Time trends.

Figure 1.

Life expectancy at age 65 (left plot) and subpopulation-specific disparities (right plot). State disparities reflect leading states (Hawaii, Florida, Arizona, California, New York, Connecticut, Minnesota, and Colorado) vs, lagging states (Arkansas, Tennessee, Louisiana, Oklahoma, Kentucky, Alabama, Mississippi, and West Virginia). Race disparities reflect White vs. Black. B-splines with two internal nodes in 2005 and 2011 were used to smooth the curves.

Figure 2.

The cause-specific contributions to the differences in life expectancy at 65 given by eqns. (8) and (9). Estimates are shown for racial (red), geographic (blue), and time-related (green) disparities using Medicare (closed dots) and Multiple Cause of Death data (open dots). The last line shows disparities for the group of individuals without established diagnoses in Medicare records (the blue point that shows the geographic disparity has to be multiplied by 3 to obtain actual value).