Dissertations and Theses

Date of Degree


Document Type


Degree Name

Doctor of Public Health (DPH)


Environmental, Occupational, and Geospatial Health Sciences


Denis Nash

Committee Members

Thomas Matte

Glen Johnson

Subject Categories

Epidemiology | Maternal and Child Health | Public Health


Asthma, interrupted time series, medication adherence, health care utilization


Background: In New York City, asthma continues to be the leading cause of hospitalizations and emergency department (ED) visits among children, and disproportionally burdens Black and Latino children in low-income neighborhoods. Place-based, or geographically targeted, programs offer upstream strategies for addressing public health issues in these underserved neighborhoods, and given their targeted nature, quasi-experimental or other observational methods are needed to rigorously evaluate their impact. This dissertation uses multiple methodological approaches to assess the impact of the East Harlem Asthma Center of Excellence (EHACE) – an equity-focused, multi-faceted, place-based asthma mitigation initiative in the East Harlem neighborhood of a New York City, instituted in 2008, on population-level asthma-related morbidity among children ages 0 to 17. We use the same multi-methodological approaches to examine the impact of the COVID-19 pandemic restrictions and closures on asthma-related preventable and preventative health care utilization and asthma medication adherence and prescribing among Medicaid-enrolled children residing in East Harlem.

AIM 1: Evaluate the population-level impact of EHACE on asthma-related morbidity among children and youth aged 0 to 17 years residing in East Harlem.

AIM 2: Assess the impact of COVID-19 pandemic-related restrictions and closures in New York City on asthma-related preventable (ED visits, hospitalizations) and preventative (well child visits, telehealth visits) health care utilization among Medicaid-enrolled children ages 0 to 17 years in East Harlem vs. two comparison populations in the Bronx and Brooklyn.

AIM 3: Assess the impact of COVID-19-related health care disruptions on the prescribing of asthma controller medications by health care providers and medication adherence among Medicaid-enrolled children aged 2 to 17 years with persistent asthma residing in East Harlem vs. three comparison populations (Brooklyn, the Bronx, and citywide comparisons).

Methods: We employed an interrupted time series design and a quasi-Poisson segmented regression analyses using population-based administrative data for 2002-2014 hospital discharges and 2005-2014 emergency department (ED) visits, adjusting for seasonality and other time-varying covariates. Comparison populations in Brooklyn and the Bronx were identified through principal components analysis and were similar to the East Harlem catchment population with respect to both asthma burden, and socioeconomic and demographic characteristics. A difference-in-difference design was applied to statistically compare the pre (2002-2007)-to-post (2008-2014)-intervention changes in asthma-related morbidity rates and pre-to-post slope differences of the comparison populations compared to the target populations, using rate ratios as a relative measure of impact.

To assess the impact of the COVID-19 pandemic on asthma-related health care utilization, we used 2018-2021 administrative New York State Medicaid data (ED visits, hospitalizations, well-child visits, and telemedicine) and New York City syndromic surveillance ED data. We used quasi-Poisson segmented regression with difference-in-difference to make statistical comparisons between the changes in rates of asthma-related health care utilization among children on Medicaid between the pre- (Jan 1, 2018-Mar 31, 2020) and pandemic (Apr 2020 – Dec 31, 2021) time periods and pre-to-post slope differences. For Aim 3, where we used Medicaid claims and prescription data to construct a cohort of children aged 2 to 17 years with persistent asthma, to assess changes in asthma medication adherence and Asthma Medication Ratio (AMR) – a proxy measurement of the quality of asthma care – after the start of the COVID-19 pandemic (April 1, 2020-December 31, 2021) compared to the pre-pandemic period (January 1, 2018 – March 31, 2020). Using an interrupted time series with difference-in-difference design, we conducted multivariable regression analysis using log-linear Poisson segmented regression.

Results: East Harlem demonstrated a relative reduction of 31% (Rate Ratio (RR)=0.69, 95% CI=0.49, 0.98) and 28% (RR=0.72, 95% CI=0.53 ,0.98) in the monthly rates of asthma-related hospitalizations and ED visits, respectfully, during the post- vs pre-EHACE timeframes. Similarly, results for the Brooklyn comparison population demonstrated a relative reduction of 30% (RR=0.70, 95% CI=0.55, 0.87) and 23% (RR=0.77, 95%CI=0.62, 0.96) in the monthly rates of asthma-related hospitalizations and ED visits, respectively. Results from the difference-in-difference suggested a relative difference of 2% (RR=0.98, 95% CI=0.97, 0.99), between the East Harlem vs. the Brooklyn comparison population in the monthly slope change (i.e., pre- vs. the post-intervention) of asthma-related ED visits, but no statistically significant differences between the target and the Bronx comparison populations. The East Harlem and the two comparison populations did not experience an immediate impact in asthma-related hospitalization/ED visit rates following the opening of EHACE.

All three populations of Medicaid-enrolled children ages 0 to 17 experienced comparable decreases in asthma-related ED visits in the month immediately following the closures of New York City schools and the New York State PAUSE order – an 86% relative reduction among the EHACE catchment area (RR=0.14, 95% CI= 0.09, 0.23), compared to an 87% reduction among the Bronx (RR=0.13, 95% CI= 0.08, 0.21) and Brooklyn (RR=0.13, 95% CI= 0.09, 0.20) comparison populations. There was an immediate relative reduction in asthma-related hospitalization rates of 74% (RR=0.26, 95% CI=0.14, 0.45) among Medicaid-enrolled children in East Harlem and 78% in the Bronx (RR=0.22, 95%CI = 0.13, 0.35), compared to a smaller, but statistically significant, relative reduction of 57% (RR=0.43, 95% CI=0.22, 0.84) among children in the Brooklyn comparison population. Rates of preventative (i.e., well-child visits) utilization for asthma drastically declined in April (compared to March), immediately following the start of COVID-19 pandemic. Telemedicine visits for asthma across all populations, significantly increased immediately following the closure of schools and the implementation of the New York State PAUSE order.

Finally, there were no statistically significant changes in medication adherence among Medicaid-enrolled children immediately following the start of the COVID-19 pandemic in any population. Overall, medication adherence was lowest among the children in the older age category of 12 to 17 years. There were increases in AMR across all populations immediately following the start of the COVID-19 pandemic, all of which were statistically significantly different from that during the pre-pandemic period.

Conclusion: The results demonstrate changes in the post-EHACE slope (vs. pre-intervention slope) of asthma-related morbidity rates, suggesting EHACE may have had a small and gradual population-level impact on reducing asthma-related morbidity among children living in East Harlem following its inception. The COVID-19 pandemic drastically challenged the continuity of care model for asthma management and caused a precipitous disruption in health care services and availability of care, with analogous patterns of asthma-related preventative and preventable utilization observed across New York City. Both preventable and preventative health care utilization decreased immediately following the start of the COVID-19 pandemic but slowly increased over the course of the pandemic period. Telemedicine rates drastically increased once COVID-19 restrictions were implemented, with rates appearing to decrease during the months following the start of the pandemic. Despite the drastic disruption COVID-19 had on health care services across New York City, however, there were no marked changes in asthma medication adherence and unexpected improvements in the quality of asthma care among a cohort of Medicaid-children residing in East Harlem. This study provided insight on the adaptability and proactiveness of caregivers of asthmatic children during the COVID-19 pandemic. Findings from this dissertation research can be used to inform the need for the expansion and reach of sustainable place-based asthma mitigation programs in neighborhoods with high rates of asthma-related morbidity and elsewhere.



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