摘要：Objectives. We sought to determine whether aggregate national data for American Indians/Alaska Natives (AIANs) mask geographic variation and substantial subnational disparities in prenatal care utilization. Methods. We used data for US births from 1995 to 1997 and from 2000 to 2002 to examine prenatal care utilization among AIAN and non-Hispanic White mothers. The indicators we studied were late entry into prenatal care and inadequate utilization of prenatal care. We calculated rates and disparities for each indicator at the national, regional, and state levels, and we examined whether estimates for regions and states differed significantly from national estimates. We then estimated state-specific changes in prevalence rates and disparity rates over time. Results. Prenatal care utilization varied by region and state for AIANs and non-Hispanic Whites. In the 12 states with the largest AIAN birth populations, disparities varied dramatically. In addition, some states demonstrated substantial reductions in disparities over time, and other states showed significant increases in disparities. Conclusions. Substantive conclusions about AIAN health care disparities should be geographically specific, and conclusions drawn at the national level may be unsuitable for policymaking and intervention at state and local levels. Efforts to accommodate the geographically specific data needs of AIAN health researchers and others interested in state-level comparisons are warranted. The 2007 National Healthcare Disparities Report suggests that many indicators of disparity in quality of care between American Indians/Alaska Natives (AIANs) and Whites and most indicators of disparity in access to care between the 2 groups are improving. 1 However, these conclusions are drawn from nationally aggregated data. Questions remain about whether, and to what extent, national data on AIAN disparities mask geographic variation in access to care and disparities in access at subnational levels (e.g., states and localities). Access to care is a critical element to improving health status and is 1 of the 10 Leading Health Indicators that is monitored at the national level. 2 Each Leading Health Indicator has Healthy People 2010 objectives associated with it. For example, the objectives used to monitor access to care in the United States are (1) insurance coverage, (2) having a usual source of care, and (3) prenatal care utilization. 2 For this article, we focus on prenatal care as a key indicator to measure both access to care and disparities in access for the AIAN population. It is generally assumed that women who receive adequate prenatal care have better birth outcomes, although the relevant content and effectiveness of prenatal care remain debatable. 3 , 4 Initiating prenatal care early in pregnancy and continuing with prescribed visits provides opportunity for medical management of health complications, lifestyle and health behavior advice, and referral to additional health and social welfare resources when necessary. Between 1990 and 1998, the proportion of all infants whose mothers began prenatal care in the first trimester increased, but the rate for AIANs still lagged behind other population groups. The rate for AIANs increased from 58% to 69%, compared with an increase from 83% to 88% for non-Hispanic Whites. 5 Increases in early prenatal care have been greatest among those whose risk profiles and adverse birth outcome rates are highest. However, AIANs are still more than 3.6 times more likely than are non-Hispanic Whites to enter prenatal care in the third trimester or to have no prenatal care at all. 5 The Healthy People 2010 goals for the nation include goals to increase the proportion of pregnant women who receive early and adequate prenatal care. The 2 specific goals are: (1) to increase the proportion of all infants whose mothers begin prenatal care in the first trimester from a baseline of 83% to the target of 90%, and (2) to increase the proportion of all infants whose mothers have early and adequate prenatal care from a baseline of 74% to the target of 90%. 2 Although the goals are the same for all groups, the baseline rates for AIANs and non-Hispanic Whites are quite different. The baseline proportion of all infants whose mothers had adequate prenatal care was 57% for AIANs and 79% for non-Hispanic Whites. Disparities in prenatal care utilization have narrowed for some groups, 6 but AIANs have consistently recorded the highest rates of inadequate prenatal care use compared with all other races. 7 , 8 Few studies have closely examined AIAN disparities in prenatal care utilization; those that have tend to use nationally aggregated data. However, beginning with 2005 data, the National Center for Health Statistics revised its data-release policy to comply with state requirements. The revised policy is “consistent with CDC and NCHS goals to make data available as widely as possible while protecting respondent confidentiality, assuring data quality, and conforming to state laws and regulations on re-release of vital statistics data.” 9 In practice, national vital records public-use data files no longer contain geographic identifiers, making local-area analyses more difficult. We disaggregated national-level data to regional and state levels to examine whether national data on AIAN disparities mask geographic variation and substantial subnational disparities in access to health care for 2 indicators of access: late entry into prenatal care and inadequate utilization of prenatal care. Our intent is not to dispute the conclusions of the National Healthcare Disparities Report but rather to examine whether the story is more complicated than what the report indicates.
