National Mortality Databases to Assess Disease Burden in Systemic Autoimmune Diseases: A Valuable Resource, But with Limitations.

Abstract

Disease-specific mortality statistics are useful measures of disease burden. Population-based studies from a few United States counties have reported mortality in systemic autoimmune diseases (SAID). However, due to substantial differences in the population structure of these counties as well as relatively small numbers of SAID deaths in these counties, it is difficult to extrapolate their findings to assess the SAIDs' national burden. In this regard, national mortality databases offer a large reference population, which is hard to assemble in individual SAIDs. However, two concerns are persistently raised regarding mortality databases for SAIDs: misclassification and under-recording. While misclassification of SAIDs is common in health records and administrative databases, it appears to be rare on death certificates among decedents that did not have a SAID. However, SAIDs are under-recorded in death certificates. The under-recording of SAIDs does not differ by sex and race/ethnicity, but it is common in elderly that die of cardiovascular diseases, neoplasms, and chronic obstructive pulmonary disease. SAIDs' under-recording may occur, because it may be difficult to assign a specific SAID manifestation or treatment complication responsible for death. Furthermore, a SAID is commonly listed as a contributing cause, rather than as the underlying cause of death, on death certificates, which advocates using the multiple-causes-of-death database for SAIDs. Nevertheless, until we have large-scale prospective outcomes data, mortality data from the National Vital Statistics System offer the valuable estimates of SAIDs' national burden, which can be used for setting research priorities, healthcare policy planning, resource allocation, and precision public health.