Abstract
Our objective was to describe how distance to specialty clinics and availability of primary care providers affects health and service use for adults with Down syndrome in the United States. We used 2019 data from a cohort of Medicaid enrollees ≥18 years with Down syndrome. We identified specialty clinics and mapped distance from individual’s zip codes. We created quantiles by distance and primary care provider density. Our cohort of 89,382 adults showed differences in health outcomes and costs by their geographic proximity to clinics and their access to primary care providers. After adjustment, mortality rates in Quartile III of distance to the specialty clinics were 1.16 times (95% CI: 1.00, 1.34) and Quartile IV was 1.27 times (95% CI: 1.08, 1.49) that of Quartile I. Hospitalization rates were quantitatively similar across groups. Ensuring equitable access to both primary and specialized care for adults with Down syndrome remains a significant challenge.
Keywords: Down syndrome, specialty clinic, mortality, hospitalization, social determinants of health
Background
Down syndrome is the partial or full triplication of chromosome 21 and is the most common genetic cause of intellectual disability (Bull, 2020) with an estimated 125,000 adults 18 years or older with Down syndrome living in the US (Rubenstein, 2023). In the past 30 years, the average life expectancy for people with Down syndrome has significantly increased from 25 years in 1983 to 60 years in 2020 (Tsou, 2020), meaning there are more middle- and older-aged adults with Down syndrome every year. As the population ages into adulthood and older adulthood, they often need more health care services to address the increased risk of co-occurring conditions such as autoimmune disease and Alzheimer dementia (Tsou, 2020).
Two important health care resources for people with Down syndrome are specialty intellectual and developmental disability clinics and primary care providers. Specialty intellectual and developmental disability clinics use interdisciplinary teams to collaborate on comprehensive care plans for patients (Santoro, 2021), of which few focus exclusively focus on the care of children or adults with Down syndrome (Santoro, 2021). Multidisciplinary teams may consist of physicians, dietitians, speech therapists, and social workers (Rileys Children Down Syndrome Program, 2025) and studies show that multidisciplinary teams improve outcomes in chronic conditions (Wagner, 2001). An individual may go to the specialty clinic once and get needed referrals, go for regular care, or go sporadically. In contrast to the specialized nature of intellectual and developmental disability clinics, primary care providers can provide consistent care and develop rapport with patient through annual physicals and other check-ins. While some do have specialized training, most primary care providers often lack training and/or resources to provide optimal care for people with intellectual disabilities (Varshney, 2022).
Studies suggest that few adults with Down syndrome in the US receive the healthcare that they need (Tsou, 2020). Many intellectual and developmental disability clinics only serve children, leaving adults without specialty care. For Down syndrome specialty clinics (a subset of all intellectual and developmental disability clinics), there was only a combined capacity to serve 3% of adults with Down syndrome (Santoro, 2021). Primary provider care may also be lacking as many adults receive care from a pediatric focused primary care physician and are regularly not up to date on preventative healthcare activities (Jensen, 2020; Skotko, 2013).
People with Down syndrome can live in health deprived areas, where limited healthcare resources make it challenging to access the comprehensive care needed to support increasing life expectancy in this population. Due to lack of specialty clinics and their limited capacity, people with Down syndrome are reliant on receiving care from their primary providers, who may lack training and knowledge for providing care for adults with disabilities (Wilkinson, 2012). It is also unclear to what extent U.S. medical education focuses on caring for patients with disabilities, and how that contributes to poorer health outcomes (Wilkinson, 2012). These are also issues that impact the wider intellectual disability population in the US and globally (Barrington, 2024). Understanding primary care provider availability is crucial to understanding gaps in care, given the reliance on these providers due to the limited number of specialized clinics. Alternative models that integrate tele-health and video conferencing to caregivers and primary care providers could also help address the scarcity of specialty clinics and the challenges in accessing them (DSC2U, 2024; Project ECHO, 2024).
It is important to examine specialty clinics and primary care in context of what we know about how distance and access to healthcare impacts health. A 2020 study by Joslyn et al sought out to assess accessibility to Down syndrome specialty care clinics by simulating where people with Down syndrome live and calculating the distance to travel to reach a specialty Down syndrome clinic, estimating that 1 in 5 individual faced geographic barriers to receiving specialty care (Zhu. 2014). While this study highlighted the significant obstacles individuals with Down syndrome face in accessing specialty care, work is needed that focuses on adult clinics using actual residential data.
Our primary objective was to describe how distance to specialty intellectual and developmental clinics and the availability of primary care providers affects health outcomes and service use for adults with Down syndrome in the United States. We examined mortality, hospitalization, claims, and cost rates among adults with Down syndrome in a complete Medicaid sample from 2019.
Methods
Cohort
Our adult Down syndrome population was derived from the Down Syndrome Toward Optimal Trajectories and Health Equity using Medicaid Analytic eXtract project (DS-TO-THE-MAX). DS-TO-THE-MAX is a cohort of Medicaid enrollees ≥18 years of age who have claims for Down syndrome (2). Medicaid is a health insurance provider for low-income and/or people with disabilities in the U.S. Almost all adults with Down syndrome are enrolled in Medicaid given that few have employer-based insurance due to the low full-time employment rate in the Down syndrome population (12). Data include beneficiary demographics, all inpatient hospitalization, and other service claims, encounters, and cost data. We excluded those without a zip code in the data (N=1,043, 1.2% of all with Down syndrome). This project was deemed not human subjects research by the Boston University Medical Campus Institutional Review Board and a waiver of consent was not necessary.
Identification of specialty clinics serving adults with Down syndrome
To identify specialized clinics that would serve adults with Down syndrome, we utilized online resources from the Global Down Syndrome Foundation and National Down Syndrome Society websites (Global Down Syndrome, 2024; National Down Syndrome Society, 2024), consulted subject matter experts, and contacted clinics to ensure it met our inclusion criteria as specialty clinic. To qualify as a specialty clinic for our study, clinics needed to treat adults with intellectual and developmental disabilities ≥18 years (including, but not limited to, those clinics that exclusively focused on Down syndrome), were established prior to 2019, and offer healthcare services. We focused exclusively on clinics that provided comprehensive care services to address the multifaceted needs of individuals with Down syndrome and to address our study outcomes effectively. We identified 27 specialty clinics in the continental US that serve adults with Down syndrome found in Supplemental 1A.
Mapping Analysis
We captured the geographic distribution of adults with Down syndrome in 2019 by using the centroid of enrollees’ zip codes and calculating the distance to the nearest clinic. We restricted to zip codes and clinics that were in the continental US, and each zip code was matched to the nearest specialty clinic. Each zip code was matched to only one clinic. Driving distance (miles) and time (minutes) were calculated using ArcGIS Pro 3.1.0. ArcGIS was also used to perform geocoding and mapping by density of population size and distance to clinics.
Outcome measurement
Our main outcomes of interest for our analysis were death, inpatient hospitalization, total cost, and total number of claims. Death date was derived from the Centers of Medicare and Medicaid services demographic dataset and was only available if an individual was enrolled at time of death. We evaluated hospitalizations because they are a commonly used prevention quality indicator (Hughes, 2008). We created a count of hospitalizations based on unique claims with nonoverlapping admission dates and divided by person-years to calculate hospitalization rate. To evaluate interactions with the health care system, we examined mean and median number of claims per person-year. Claims were from the inpatient, other services, and long-term care files. We determined the amount Medicaid paid per individual in 2019. The Medicaid paid amount is the amount of money that the Medicaid system paid the clinician and does not reflect the original billed amount or out-of-pocket expenses. We included capitated payments to account for services provided by managed care organizations (Centers for Medicare and Medicaid Services, 2022).
Statistical Analysis
We categorized distances in miles to specialty intellectual and developmental disability clinics into four quartiles with each quartile defined based on distances from the clinics. We presented descriptive data for demographic characteristics by quartile and identified clinics by state and region. We ran an unadjusted regression model followed by an adjusted model with the following covariates: age, sex, rurality, poverty level, and a random effect by state to account for state policy differences and region variation. Rurality and poverty level metrics were derived from the American Community Survey 2020 data metrics (US Census Bureau). To examine the association between distance to clinics and death rates, we used a binomial mixed effects model. For our hospitalization analysis, we initially used a Poisson model to explore associations, but given the overdispersion in hospitalization data, we opted for a negative binomial model. To assess healthcare costs and claims, we filtered out non-positive values (i.e. Medicaid reimbursements) and utilized a Gamma regression model.
To assess primary care provider outcomes, we used the ratio of primary care physicians by county size as a proxy for primary care availability. Data were derived from the 2019 County Health Rankings (2019). Counties were sorted by county-level Federal Information Processing Standard (FIPS) codes and given a within-state rank of primary care providers to population ratio. The County Health Rankings created four quantiles with one representing the highest density of primary care providers to county size, and four representing least providers in relation to county size (County Health Rankings, 2019). County level FIPS codes were linked to the DS-TO-THE-MAX cohort. For our analysis, zip codes in Quantiles 3 and 4 from the County Health Rankins were combined because relatively few people with Down syndrome lived in those zip codes and led to unequal quantiles in our data. We categorized quantiles for primary care providers into high (Quantile 1), Medium (Quantile 2) and low (Quantiles 3 +4).
Coefficients from each model were transformed into incident rate ratios, and we calculated 95% confidence intervals. The same models and methods were used to assess distances to clinics and primary care physician density and its effect on our primary outcomes. All statistical analyses were performed in R version 4.4.0.
Results
Demographics
Our sample of Medicaid-enrolled adults with Down syndrome in the continental U.S. in 2019 included 89,382 individuals. Most enrollees from each quantile were white (range between quartiles: 65.2–79.9%) (Table 1) and were dual enrolled with Medicare. When looking at demographics by primary care provider availability, 35,547 enrollees were in areas with the highest availability, 18,938 in areas with medium primary care provider availability, and 17,258 enrollees lived in areas with low primary care provider availability. Areas with a medium level of primary care providers had the highest proportion of Hispanic/Latino enrollees (17.3%) compared to high (13.9%) and low availability (10.1%).
Table 1.
Demographic Table of Medicaid adults with Down syndrome in 2019 by Distance (Quantile) and Primary Care Availability
| Distance to Specialty Clinic, by Quartiles | Primary Care Provider Availability | |||||||
|---|---|---|---|---|---|---|---|---|
| Quartile I (0–48 mi) N=22,310 | Quartile II (49–123 mi) N=22,373 | Quartile III (124–245 mi) N=22,352 | Quartile IV (>246 mi) N=22,347 | High Availability (N=35,547) | Medium Availability (N=18,938) | Low Availability (N=17,258) | ||
| Deaths in 2019 | Total= 2,863 | 649 (22.7) | 758 (26.5) | 773 (27.0) | 683 (23.9) | 1111 (46.4) | 639 (26.7) | 643 (26.8) |
| Age at study enrollment (2019) | 18–25 | 5060 (22.7) | 4609 (20.6) | 4534 (20.3) | 4956 (22.2) | 7756 (21.8) | 4062 (21.4) | 3285 (19.0) |
| 26–34 | 5689 (25.5) | 5386 (24.1) | 5281 (23.6) | 5581 (25.0) | 8563 (24.1) | 4540 (24.0) | 4008 (23.2) | |
| 35–44 | 4044 (18.1) | 4085 (18.3) | 4269 (19.1) | 4484 (20.1) | 6421 (18.1) | 3498 (18.5) | 3426 (19.9) | |
| 45–54 | 3653 (16.4) | 3939 (17.6) | 4057 (18.2) | 3691 (16.5) | 6229 (17.5) | 3366 (17.8) | 3127 (18.1) | |
| 55–64 | 3109 (13.9) | 3479 (15.5) | 3350 (15.0) | 2952 (13.2) | 5322 (14.9) | 2790 (14.7) | 2736 (15.9) | |
| 65–89 | 755 (3.4) | 875 (3.9) | 861 (3.9) | 683 (3.1) | 1256 (3.5) | 682 (3.6) | 676 (3.9) | |
| Race † | White | 14,251 (65.2) | 16,822 (76.2) | 17,405 (79.9) | 15,690 (72.0) | 25856 (74.5) | 13784 (74.7) | 14326 (84.7) |
| Black | 4,008 (18.3) | 3,209 (14.5) | 3,049 (14.0) | 2,267 (10.4) | 6243 (18.0) | 2822 (15.3) | 1733 (10.2) | |
| Pacific Islander | 137 (0.6) | 101 (0.5) | 109 (0.5) | 425 (2.0) | 219 (0.6) | 180 (1.0) | 86 (0.5) | |
| Asian | 1,225 (5.6) | 730 (3.3) | 274 (1.3) | 937 (4.3) | 943 (2.7) | 522 (2.8) | 158 (0.9) | |
| Native American | 45 (0.2) | 86 (0.3) | 140 (0.6) | 456 (2.1) | 220 (0.6) | 152 (0.8) | 151 (0.9) | |
| Mixed | 2,209 (10.1) | 1,119 (5.1) | 807 (13.1) | 2,030 (9.3) | 1244 (3.6) | 981 (5.3) | 459 (2.7) | |
| Ethnicity †† | Non-Hispanic/Latino | 17,216 (78.7) | 18,374 (83.3) | 18,946 (87.0) | 16,875(77.4) | 29903 (86.1) | 15246 (82.7) | 15198 (90.0) |
| Hispanic/Latino | 4659 (21.3) | 3,693 (16.7) | 2,838 (13.0) | 4,930 (22.6) | 4822 (13.9) | 3195 (17.3) | 1715 (10.1) | |
| Sex | Male | 11,419 (51.1) | 11585 (51.8) | 11788 (52.7) | 11678 (52.2) | 18871 (53.0) | 9857 (52.0) | 9118 (52.8) |
| Female | 10,891 (48.8) | 10788 (48.2) | 10564 (47.2) | 10669 (47.7) | 16676 (47.0) | 9081 (48.0) | 8140 (47.1) | |
| Region | Northeastern | 5035 (5.6) | 9360 (41.8) | 4297 (19.2) | 1166 (5.2) | 7386 (20.8) | 6777 (35.8) | 4552 (26.3) |
| Midwest | 5949 (26.7) | 4677 (20.9) | 5974 (26.7) | 4039 (18.1) | 10686 (30.1) | 4717 (24.9) | 5143 (29.8) | |
| South | 4943 (22.2) | 5082 (22.7) | 9744 (43.6) | 8773 (39.2) | 14937 (42.0) | 5780 (30.5) | 6079 (35.2) | |
| West | 6379 (28.6) | 3249 (14.5) | 2331 (10.4) | 8366 (37.4) | 2530 (7.1) | 1661 (8.8) | 1481 (8.6) | |
| Eligibility Type (Ever) | Disability | 17275 (77.4) | 17799 (79.6) | 18220 (81.5) | 16926 (75.7) | 28246 (50.0) | 14784 (26.0) | 13811 (24.2) |
| Income | 13181 (59.1) | 12282 (54.9) | 12467 (55.8) | 13935 (62.4) | 19221 (49.4) | 10992 (28.3) | 8644 (22.2) | |
| Dual enrollment Medicare | Yes | 12113 (54.3) | 13416 (60.0) | 13914 (62.2) | 12749 (57.1) | 21350 (60.1) | 11349 (59.9) | 11095 (64.3) |
| No | 10197 (45.7) | 8957 (40.0) | 8438 (37.8) | 9598 (42.9) | 14197 (39.9) | 7589 (40.1) | 6163 (35.7) | |
We mapped the intellectual and developmental disability specialty clinics and density of enrollees with Down syndrome in Figure 1. When looking at adults with Down syndrome by region, we found 19,858 (22.22%) were living in the Northeast, 20,639 (23.10%) were in the Midwest, 28,542 (31.94%) in the South, and 20,325 (22.74%) in the West (Table 2). Among these regions, there were five intellectual and developmental disability specialty clinics in the Northeast, eight intellectual and developmental disability specialty clinics in the South and Midwest, and six intellectual and developmental disability specialty clinics in the West (Table 2).
Figure 1.
Intellectual and developmental disability specialty clinic locations and density of adults with Down syndrome in 2019 in the continental US
Table 2.
Adult Down Syndrome intellectual and developmental disability specialty clinics and adult Down syndrome population by State and Region in 2019
| Region | States | Individuals with Down syndrome | No. of clinics |
|---|---|---|---|
| Northeast | Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, Vermont, New Jersey, New York, Pennsylvania | 19,858 (22.22%) | 5 |
| Midwest | Illinois, Indiana, Michigan, Ohio, Wisconsin, Iowa, Kansas, Minnesota, Missouri, Nebraska, North Dakota, South Dakota | 20,639 (23.10%) | 8 |
| South | Delaware, District of Columbia, Florida, Georgia, Maryland, North Carolina, South Carolina, Virginia, West Virginia, Alabama, Kentucky, Mississippi, Tennessee, Arkansas, Louisiana, Oklahoma, Texas | 28,542 (31.94%) | 8 |
| West | Arizona, Colorado, Idaho, Montana, Nevada, New Mexico, Utah, Wyoming, California, Oregon, Washington | 20,325 (22.74%) | 6 |
Death and Hospitalization rates by Distance to intellectual and developmental disability specialty clinics
After adjusting for potential confounders, mortality rates in Quartile III were 1.16 times (95% CI: 1.00, 1.34) and Quartile IV was 1.27 times (95% CI: 1.08, 1.49) that of Quartile I (Figure 2A.). Hospitalization rates were quantitatively similar across groups (max 19.8 hospitalizations per 100 person years, min: Quartile III 17.0 hospitalizations per 100 person years). After adjusting for confounders, there were minimal changes in estimates.
Figure 2. Healthcare outcomes by distance to Intellectual and Developmental Disability Specialty Clinics in Medicaid enrolled adults with Down syndrome, 2019.
A. Death*
B. Hospitalization*
C. Total Cost*
D. Total Claim*
*(adjusted for age, sex, rurality, poverty level, and random effects by state)
Point estimates and 95% CI values are presented in Supplement 2A
Total Costs and Claim rates by Distance to intellectual and developmental disability specialty clinics
Total cost rates were highest in Quartile II at $56,325 per enrollee (95% CI: 55,567–57,084), with the lowest being observed in Quartile III $44,908 (95% CI: 44,272–45,544). After adjusting for confounders, costs in Quartile II decreased to 1.03 (95% CI: 1.01, 1.06) (Figure 2C.) times that of Quartiles I. Quantile III and IV increased to 0.97 (95% CI: 0.95, 1.00) and 1.03 (95% CI: 1.00, 1.05) (Figure 2C) times that of Quartile I. Total claim rates were also highest in Quartile II (252.1 claims per person year 95% CI: 249–255.3) with lower mean number of claims in Quartile III and IV (220.27 and 218.18 respectively). After adjusting for confounders, there were no meaningful differences between the Quartiles (Figure 2D).
Death and Hospitalization rates by primary care provider availability by County
Areas with the highest primary care provider availability had a death rate of 31.3 per 1000 enrollees (95% CI: 29.4–33.0), while areas with the lowest availability, had a death rate of 37.3 per 1000 enrollees (95% CI: 34.4–40.1) (Table 3). After adjusting for relevant confounders, there were no meaningful differences in death rate. In both the unadjusted and adjusted model, we observed no meaningful differences between hospitalizations and primary care provider availability (Table 3).
Table 3.
Death, Hospitalization, Total Cost, and Total Claim rates by Distance to Intellectual and Developmental Disability Specialty Clinics and Primary Care Provider Availability in Medicaid enrolled adults with Down syndrome, 2019
| Death rate /per 1000 enrollees | Hospitalization Rate /per 100 enrollees | Total Cost per person year | Total Claims per person year | |
|---|---|---|---|---|
| Distance | ||||
| Quartile I (0–48 mi) | 29.1 [26.0–31.2] | 19.8 [19.3–20.3] | $49,234 [48,559–49,909] | 238.83 [235.8–241.8] |
| Quartile II (49–123 mi) | 33.9 [31.5–36.2] | 19.1 [18.6–19.6] | $56,325 [55,567–57,084] | 252.14 [249–255.3] |
| Quartile III (134–245 mi) | 34.6 [32.1–37.0] | 17.0 [16.5–19.6] | $44,908 [44,272–45,544] | 220.27 [217.2–223.3] |
| Quartile IV (>245 mi) | 30.6 [28.3–32.8] | 19.3 [18.7–19.8] | $47,726 [47,153–48,299] | 218.18 [215.2–221.2] |
| Primary care provider density | ||||
| High Availability | 31.3 [29.4–33.0] | 19.3 [18.9–19.7] | $51,001 [50457–51546] | 246.2 [243.6–248.8] |
| Medium Availability | 33.7 [31.1–36.3] | 18.5 [17.9–19.0] | $49,348 [48605–50090] | 248.5 [245.1–251.9] |
| Low Availability | 37.3 [34.4–40.1] | 18.1 [17.5–18.7] | $46,220 [45506–46935] | 230.5 [227.1–234] |
Total Cost and Claim rates by primary care provider availability by County
Total costs per enrollee were highest in areas with high primary care provider availability ($51,001 per enrollee 95% CI: 50,457–51,546) and lower in areas with the lowest availability ($46,220 per enrollee 95% CI: 45,506–46,935) (Table 3). After adjusting for relevant cofounders, costs for medium and lower-level availability decreased to 0.90 (95% CI: 0.89, 0.92) and 0.88 (95% CI: 0.86, 0.90) times that of the highest availability (Figure 3C).
Figure 3. Healthcare outcomes by primary care provider availability in Medicaid enrolled adults with Down syndrome, 2019.
A. Death*
B. Hospitalization*
C. Total Cost*
D. Total Claim*
*(adjusted for age, sex, rurality, poverty level, and random effects by state)
Point estimates and 95% CI values are presented in Supplement 2
Total claim rates were similar among those with high to medium primary care provider availability (high: 246.2 (95% CI: 243.6–248.8) and medium: 248.5 claims per enrollee (95% CI: 245.1–251.9) and lowest in low: 230. 5 (95% CI: 227.1–234) (Table 3). When looking at total claims in relation to availability, our adjusted model showed a decrease for those in medium level (rate ratio: 0.95, 95% CI: 0.94, 0.97) (Figure 3D).
All unadjusted and adjusted rates with confidence intervals can be found in Supplemental 2A and 2B.
Discussion
Healthcare for adults with Down syndrome is often lacking and the impact of geographic determinants are under examined. Our study offers a comprehensive analysis of Medicaid-enrolled adults with Down syndrome and healthcare outcomes by distances to intellectual and developmental disability specialty clinics and primary care provider density in the United States. In our cohort of 89,382 adults, we saw differences in health outcomes and costs by their geographic proximity to clinics and their access to primary care providers.
Geographic accessibility to healthcare services is a critical determinant of healthcare utilization and health outcomes. Factors such as access to care, income, gender, and race, all contribute to exacerbating disparities in the Down syndrome population (7). Our work builds off the work of Josyln et. al (2020), who projected distance to Down syndrome clinics for individuals with Down syndrome using 2015 estimates. Unlike their use of simulated population data to estimate the Down syndrome population in the US, our cohort included exact figures using enrollee data zip code from the Down syndrome Medicaid population. This allowed us to more accurately assess the distribution of the Down syndrome population across the continental US, and their proximity to available clinics.
There are few intellectual and developmental disability specialty clinics that serve adults, and their locations are densely clustered in some geographic areas and sparse in others. Based on attenuation of our adjusted estimates, geographic area is also associated with other health disparities, such as being minoritized race/ethnicity. While we were unable to evaluate which individuals in our data went to these clinics, these data highlight the significant gap in healthcare access for adults with Down syndrome and barriers they face when it comes to seeking out specialized care. When there are clinics nearby, limited capacity restricts access. One study found that Down syndrome specialty clinics had the capacity to care for 6,517 adults, which only met the needs of approximately 5% of the population (Santoro, 2021).
Healthcare claims, costs, hospitalizations, and mortality provide insight into barriers of healthcare access but are still crude measures to assess the burden individuals with Down syndrome face when trying to access care. These metrics do not capture the quality and consistency of care, which is important for those who face co-morbidities. Quality metrics such as patient satisfaction and timeliness of care would offer a more nuanced understanding of how effectively the needs of this population are being met in the long run.
Limitations
We were reliant on Global Down Syndrome Foundation and the National Down Syndrome Society websites to identify clinics and it is possible that these lists were not exhaustive, which may underestimate the number of clinics that are available in the continental U.S. We utilized these websites because they are the same resources families and caregivers would use when searching for a specialty clinic, and since there is no clear definition of what qualifies as a “specialty clinic”. Because of lags in data availability, data are not as current as would be ideal and this work should be continuously tracked over time. Clinics were also used as proxies for specialized care since we do not have any information as to whether people from our cohort attended these clinics. This is typical for this type of ecologic research. We also did not factor in clinic capacity; since most clinics are already at capacity, we have likely overestimated the number of individuals who are able to be seen at a clinic. Lastly, when looking at primary care availability by county, we linked zip codes to country-level FIPS codes, which did not capture places with smaller zip code areas. We were also not able to link in measures at the county or census bloc-group level.
Our study had several strengths. We were able to identify variations in healthcare outcomes based on geographic accessibility to clinics and primary care provider availability using a nearly full sample of those who have Down syndrome in the U.S. Our analysis benefitted from a large sample size by using Medicaid claims to identify Down syndrome enrollees. We were also able to incorporate data from the American community survey which gave us insight to poverty level and urban/rural metrics when building our models. We were also successfully able to calculate distances among all intellectual and developmental disability specialty clinics and Down syndrome enrollees in the continental US.
Conclusion
Ensuring equitable access to both primary and specialized care for adults with Down syndrome remains a significant challenge, and addressing these gaps could reduce mortality and improve health outcomes and quality for this population. Increasing the number of intellectual and developmental disability specialty clinics and primary care providers, especially in deprived regions, could provide more consistent and comprehensive care
Supplementary Material
Funding:
This was supported by the National Institute on Aging grant numbers R01AG073179, R01AG073179-S
Competing interests:
Dr. Skotko occasionally consults on the topic of Down syndrome through Gerson Lehrman Group. He receives remuneration from Down syndrome non-profit organizations for speaking engagements and associated travel expenses. In the past two years, Dr. Skotko received annual royalties from Woodbine House, Inc., for the publication of his book, Fasten Your Seatbelt: A Crash Course on Down Syndrome for Brothers and Sisters. Within the past two years, he has received research funding from AC Immune and LuMind IDSC Down Syndrome Foundation to conduct clinical trials for people with Down syndrome. Dr. Skotko is occasionally asked to serve as an expert witness for legal cases where Down syndrome is discussed. Dr. Skotko serves in a non-paid capacity on the Honorary Board of Directors for the Massachusetts Down Syndrome Congress and the Professional Advisory Committee for the National Center for Prenatal and Postnatal Down Syndrome Resources. Dr. Skotko has a sister with Down syndrome.
Dr. Santoro has received research funding from LuMind IDSC Down Syndrome Foundation to conduct clinical trials for people with DS within the past two years. She serves in a non-paid capacity on the Medical and Scientific Advisory Council and the Board of the Massachusetts Down Syndrome Congress, the Board of Directors of the Down Syndrome Medical Interest Group (DSMIG-USA), and the Executive Committee of the American Academy of Pediatrics Council on Genetics
Footnotes
Ethics approval and consent to participate: This project was deemed not human subjects research by the Boston University Medical Campus Institutional Review Board and consent was deemed unnecessary.
Contributor Information
Salina Tewolde, Boston University School of Public Health, Epidemiology.
Brian Skotko, Massachusetts General Hospital; Harvard Medical School, Pediatrics.
Stephanie Santoro, Massachusetts General Hospital; Harvard Medical School, Pediatrics.
Marcia Pescador Jiménez, Boston University School of Public Health, Epidemiology.
Alyssa Santoso, Boston University School of Public Health, Epidemiology.
Eric Rubenstein, Boston University School of Public Health, Epidemiology.
Availability of data and materials:
Data cannot be shared under a data use agreement with the Centers for Medicare and Medicaid Services.
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This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
Data Availability Statement
Data cannot be shared under a data use agreement with the Centers for Medicare and Medicaid Services.