The Feasibility of Using Electronic Health Data for Research on Small Populations. Coverage of Asian-American subpopulations in federal data collection


The best information about Asian-American subpopulations comes from the U.S. Census, but little information is collected there about health and health care. The Current Population Survey and American Community Survey (ACS) do collect information on health insurance that can be broken down by subpopulation. The ACS also collects information on disability. The Census Bureau has recently released criteria around an option for federal agencies to use the ACS as a sampling frame for follow-on surveys for rare populations, potentially allowing for further data collection from Asian subpopulations or other small populations as identified through the ACS.58 However, these follow-on surveys are expensive, and, as is further discussed below, there remain challenges in identifying some Asian subpopulations through the census.

Limited health information about Asian-American subpopulations is available in some federal surveys, including the National Health Interview Survey (NHIS), the National Health and Nutrition Examination Survey (NHANES), the MEPS, and the Early Childhood Longitudinal Survey (see Table I.3). However, within a racial group (Asians) that comprises only 4.4 percent of the populations, sample sizes of subpopulations are often too small to permit meaningful data analysis, particularly when co-variates such as age, sex, or region are factored in. Also, a sampling bias arises in surveys that collect data only in English and Spanish, as is the case with most national surveys.59 For the first time, the most recent NHANES survey oversampled Asians (including Koreans) in larger cities and worked with the Asian community and advocacy groups for outreach.60 However, a lack of interviewers able to conduct the survey in the appropriate languages and other factors like cultural attitudes and beliefs about participating in surveys may have limited participation from Asian subpopulations, thus lowering the response rate for Asian subpopulations.61

Data about Asian-American subpopulation groups are even more limited in other federal surveys. None were collected previously, for example, in the CDC’s Behavioral Risk Factor Surveillance System (BRFSS), the National Household Education Survey, the Survey of Income and Program Participation, National Survey of Family Growth, National Immunization Survey, or Medicare Current Beneficiary Survey, although many federal surveys are being updated to include this information going forward. There is also variation by state in what they collect in their National Vital Statistics, which identify Chinese, Japanese, Hawaiian, and Filipino in 50 states, but identifies other Asian subpopulations such as Vietnamese and Korean only in nine states (in which two-thirds of the Vietnamese and Korean subpopulations reside).62
Some states may collect data on Vietnamese and Koreans, but the sample sizes are too small to produce valid or reliable estimates, so they do not report figures for them at all.

Some other surveys have collected data about at least some Asian-American subgroups. The federally funded National Latino and Asian American Study collected data in 2002–03 from a nationally representative sample about the mental health needs of two rapidly growing populations. The Asian-American sample was stratified into Chinese, Vietnamese, Filipino, and Other Asians, and data were collected in Chinese, Vietnamese, and Tagalog as well as English and Spanish.63, 64 The California Health Interview Survey (CHIS), modeled after the National Health Interview Survey (NHIS), sought to include hard-to-reach populations and collected data in several Asian languages.65 Some other state or city-based surveys, such as New York City Community Health Survey, have included information on Asian-American subpopulations.

In addition to survey-based studies, studies are beginning to appear that have used EHR data to study Asian subpopulations.66, 67 This topic is the focus of the second part of this report.

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