Publications

OBJECTIVE: Urban Medicaid enrollees with opioid use disorder often rely on public transit to reach buprenorphine prescribers. Research has not shown whether public transit provides this population with adequate geographic access to buprenorphine prescribers. We examined travel times to buprenorphine prescribers by car and public transit in urban areas, and determined whether car-based Medicaid regulatory standards produce their intended geographic coverage.

METHODS: We obtained data for this study from the Substance Abuse and Mental Health Services Administration's Buprenorphine Practitioner Locator, Microsoft Bing Maps, and the American Community Survey. We examined four urban counties at the centers of the metropolitan statistical areas with the highest 2017 accidental drug poisoning death rates: Kanawha, WV; Montgomery, OH; Philadelphia, PA; and St. Louis City, MO. These counties comprised 696 census tracts representing 1,038,564 households. We calculated travel times from each census tract center to the nearest buprenorphine prescribers by car and public transit, and compared that to 30-min regulatory standards and by whether census tracts had below median levels of car access. We calculated Global Moran's I statistics to determine whether spatial clustering was present among census tracts with limited access to buprenorphine prescribers.

RESULTS: Households in all but two census tracts could access a buprenorphine prescriber within 30 min by car. However, households in 12.1% (84) of census tracts could not do so by public transit. The correlation between car- and public transit-based travel times to the nearest buprenorphine prescriber was 0.11 (95% CI = 0.07-0.22). More than 15% (47,918) of households in the two less densely populated counties could not travel to the nearest prescriber in 30 min and resided in census tracts where access to cars was relatively low. There was no evidence of spatial clustering among census tracts with public transit travel times exceeding 30 min, or among census tracts with public transit travel times exceeding 30 min and below median values of access to cars.

CONCLUSIONS: Geographic access to buprenorphine prescribers is overestimated by regulatory standards that apply car-based travel time estimates, which are a weak proxy for public transit-based travel times. Since geographic areas with limited access to buprenorphine prescribers do not tend to cluster near one another, individually targeted interventions may be necessary to improve buprenorphine access and utilization.

OBJECTIVE: To examine whether low-income children's use of preventive dental services is linked to variation in state Medicaid policies that affect parents' access to dental care in Medicaid.

DATA SOURCES: Medical Expenditure Panel Survey (2011-2016), Area Health Resources File, and Medicaid adult dental coverage policies.

STUDY DESIGN: We conducted a quasi-experimental analysis using linked parent-child dyads in low-income families (≤125 percent of the Federal Poverty Level). We assessed whether expansions of Medicaid to low-income adults under the Affordable Care Act were associated with increases in the use of preventive dental services among low-income children when state Medicaid programs did vs did not cover these services for adults.

PRINCIPAL FINDINGS: Over the study period, 37.8 percent of low-income children received at least one annual preventive dental visit. We found no change in children's receipt of preventive dental care associated with Medicaid expansions in states that covered (1.26 percentage points; 95% CI: -3.74 to 6.27) vs did not cover preventive dental services for adults (3.03 percentage points; 95% CI: -2.76 to 8.81). (differential change: -1.76 percentage points; 95% CI: -8.09, 4.56). However, our estimates are imprecise, with wide confidential intervals that are unable to rule out sizable effects in either direction.

CONCLUSION: We did not find an association between Medicaid expansions with concurrent coverage of preventive dental services for adults and children's use of these services. Factors other than parental access to dental benefits through Medicaid may be more salient determinants of preventive dental care use among low-income children.

Two-photon time-frequency entanglement is a valuable resource in quantum information. Resolving the wavepacket of ultrashort pulsed single-photons, however, is a challenge. Here, we demonstrate remote spectral shaping of single photon states and probe the coherence properties of two-photon quantum correlations in the time-frequency domain, using engineered parametric down-conversion (PDC) and a quantum pulse gate (QPG) in nonlinear waveguides. Through tailoring the joint spectral amplitude function of our PDC source we control the temporal mode structure between the generated photon pairs and show remote state-projections over a range of time-frequency mode superpositions.

AIMS: We evaluated the relationship between the timing of insulin initiation and cardiovascular diseases (CVD) risk in Pennsylvania Medicaid enrollees with type 2 diabetes (T2D).

METHODS: We included 17,873 enrollees (age 47.4 ± 10.3 years; range 18-64 years) initially treated with non-insulin glucose-lowering agents (GLAs) in 2008-2016. Based on clinical guidelines, we identified early (N = 1,158; 6%; insulin initiation ≤ 6 months after first-line GLAs), in-time (N = 569; 3%; 6-12 months), delayed (N = 2,761; 15%; >12 months), and non-insulin users (N = 13,385; 75%). The Prentice-Williams-Peterson (PWP) models with inverse probability weighting estimated CVD risk across the four groups and the change in risk after insulin initiation.

RESULTS: Regardless of time to insulin initiation, insulin users had higher CVD risks after first-line GLAs than non-insulin users (aHR: early: 2.0 [1.5-2.5], in-time: 1.8 [1.2-2.6], delayed: 1.9 [1.6-2.3]). However, we found only a borderline increase in CVD risk after insulin initiation vs. before in early (aHR: 1.4 [1.1-1.8]) and delayed users (aHR: 1.3 [1.0-1.7]), and no increase in in-time users (aHR: 1.3 [0.9-2.0]).

CONCLUSIONS: We observed no gains in CVD benefits from insulin initiation in the early stages of pharmacotherapy possibly because CVD developed before insulin initiation. Additional management of hypertension and dyslipidemia may be important to reduce CVD risk in this young and middle-aged T2D cohort.

IMPORTANCE: State decisions not to expand Medicaid under the Patient Protection and Affordable Care Act could reduce emergency access to acute care hospitals.

OBJECTIVE: To determine the relationship between state Medicaid expansion and emergency access to acute care hospitals in the United States.

DESIGN, SETTING, AND PARTICIPANTS: This cross-sectional study linked hospital-level data from the Centers for Medicare & Medicaid Services from 2007 to 2017 to US Census data for all 50 US states and the District of Columbia. Geospatial analyses and difference-in-differences regression models were used to compare temporal changes in the size of the population without 30-minute access to acute care hospitals between 32 states that expanded Medicaid with the population without access in 19 that did not, before and after expansion. Analyses focused on the total population and those with low incomes; secondary analyses examined emergency access to safety-net hospitals.

EXPOSURES: State-level Medicaid expansion.

MAIN OUTCOMES AND MEASURES: Population without emergency access to an acute care hospital, defined as living outside a 30-minute drive of any hospital.

RESULTS: States that did not expand Medicaid experienced an increase in the population without access to hospitals overall (without expansion: 6.76% to 6.79% [0.03%]; vs with expansion: 5.65% to 5.35% [-0.30%]; difference-in-differences, 0.33%; 95% CI, 0.33%-0.34%; P < .001) and for low-income persons (without expansion: 7.43% to 7.39% [-0.04%]; vs with expansion: 6.25% to 6.15% [-0.10%]; difference-in-differences, 0.06%; 95% CI, 0.05%-0.07%; P < .001). If access changes in nonexpansion states were the same as expansion states, an estimated 421 000 more persons overall and 48 000 more low-income persons would have retained access. States that did not expand Medicaid experienced an increase in the population without access to safety-net hospitals overall (46.91% to 47.70% [0.79%] vs 33.94% to 33.07% [-0.87%]; difference-in-differences, 1.66%; 95% CI, 1.64%-1.66%; P < .001) and for low-income persons (45.28% to 46.14% [0.86%] vs 33.00% to 32.23% [-0.77%]; difference-in-differences, 1.63%; 95% CI, 1.63%-1.67%; P < .001). If access changes in nonexpansion states were the same as expansion states, an estimated 2 242 000 more persons overall and 364 000 more low-income persons would have retained access.

CONCLUSIONS AND RELEVANCE: States that did not expand Medicaid under the Patient Protection and Affordable Care Act were associated with worse emergency access to acute care hospitals compared with states that expanded Medicaid.

OBJECTIVE: This study sought to characterize recent trends in mental health visits of adult outpatients to primary care physicians (PCPs), specialty mental health providers (SMHPs), and other providers (non-primary care physicians, specialists other than SMHPs, nurse practitioners, and physician assistants). Trends determined by degree of patients' psychological distress and in the types of treatments received within different settings were also examined.

METHODS: Data were from the household component of the nationally representative Medical Expenditure Panel Survey for the 2008-2011 and 2012-2015 periods for adults ages ≥18 years (N=13,111) who had a mental health outpatient visit. Bivariate logistic regression was used to compare means between the two periods.

RESULTS: The percentage of adults having mental health outpatient visits increased between the two periods, largely driven by an increase in visits with providers other than SMHPs and PCPs, which rose from 11.9% (N=667) to 15.5% (N=1,048). Outpatient mental health visits with PCPs decreased from 29.0% (N=1,802) to 26.8% (N=1,945). The proportion of respondents with mental health outpatient visits increased both among those with high psychological distress and among those with low or no psychological distress (from 30.7% [N=1,332] to 36.2% [N=1,491] and from 6.0% [N=4,516] to 6.9% [N=5,772], respectively). The percentage of respondents receiving only psychotropic medication decreased over the two periods.

CONCLUSIONS: Mental health outpatient visits for adults increased between 2008 and 2015, and visits with SMHPs remained relatively stable during that time. A greater understanding of recent trends in types of outpatient mental health services may help identify targets for future mental health workforce studies.

Objectives: Using data from the Healthcare Cost and Utilization Project (HCUP), we estimated prevalence of individual substance use disorders (SUDs) and psychiatric comorbidities among pregnant women with opioid use disorder (OUD) in the New York State from 2009 to 2014.Methods: In this cross-sectional study, pregnancy outcome and gestational age at delivery were estimated, and OUD diagnosis during pregnancy or at delivery discharge was identified. Prevalence of SUDs and psychiatric comorbidities were then calculated.Results: Among 1,463,302 pregnant women, 8324 (0.57%) were diagnosed with OUD during pregnancy or at delivery. The most frequent SUDs or psychiatric comorbidities among pregnant women with OUD were non-opioid SUD (78.2%), followed by tobacco use disorder (74.9%), generalized anxiety disorder (38.0%), major depressive disorder (36.9%), cannabis use disorder (28.3%) and cocaine use disorder (27.4%).Conclusions: Most pregnant women with OUD were diagnosed with at least one non-opioid SUD and tobacco use disorder. Generalized anxiety disorder and major depressive disorder were also common, suggesting that mental health screenings should be prioritized for pregnant women with OUD.

PURPOSE: Compared with conventional therapy (enoxaparin followed by warfarin), the direct-acting oral anticoagulant apixaban is thought to offer similar protection against recurrent venous thromboembolism (VTE) with lower bleeding risk. However, evidence regarding the heterogeneity of treatment effect from real-world data is lacking. The study described here aimed to compare the effectiveness and safety of use of apixaban versus warfarin in patients with VTE.

METHODS: We conducted a retrospective cohort analysis of commercial and Medicare supplemental databases (data coverage period, 2014-2017) among patients with a diagnosis of VTE who were new users of apixaban or warfarin. We controlled for confounding using propensity score [PS] 1:4 matching. Cox proportional hazard models were used to obtain hazard ratios (HRs) and 95% confidence intervals (CIs). Heterogeneity of treatment effect was assessed among patients with provoked VTE versus unprovoked VTE.

RESULTS: After PS matching, a total of 36,907 patients were included in the cohort (n = 8,094 apixaban users and n = 28,813 warfarin users). In Cox regression models, the use of apixaban versus warfarin was associated with lower risks of recurrent VTE (HR, 0.54; 95% CI, 0.45-0.65) and major bleeding events (HR, 0.67; 95% CI, 0.54-0.84); these results remained consistent in patients with provoked VTE and those with unprovoked VTE.

CONCLUSION: This population-based analysis of patients with VTE extends results of randomized clinical trials indicating lower risks of development of recurrent VTE and major bleeding events with use of apixaban versus warfarin in real-world settings. The observed benefits of apixaban extended to selected subgroups of the VTE population, including patients with provoked VTE.