Affiliates' Research in Medical Journals, Spring 2019

Many NBER-affiliated researchers publish some of their findings in medical journals that preclude pre-publication distribution. This makes it impossible to include these papers in the NBER working paper series. This is a partial listing of recent papers in this category.

Attention Deficit-Hyperactivity Disorder and Month of School Enrollment
T. J. Layton, M. L. Barnett, T. R. Hicks, A. B. Jena, New England Journal of Medicine, 379, November 2018, pp. 2122-30.

Most U.S. states have arbitrary age cutoffs for entry into public school. Therefore, within the same grade, children with birthdays close to the cutoff date can differ in age by nearly 1 year. Data from a large insurance database were analyzed to compare the rates of attention deficit-hyperactivity disorder (ADHD) diagnosis and treatment among children born in August vs. September in states with and states without the requirement that children be 5 years old by September 1 for enrollment in kindergarten. The data included 407,846 children in all U.S. states who were born in the period from 2007 through 2009 and were followed through December 2015. The rate of claims-based ADHD diagnosis among children in states with a September 1 cutoff was higher among those born in August than those born in September: an absolute difference of 21.5 per 10,000 children (95% CI, 8.8 to 34.0); the corresponding difference in states without the September 1 cutoff was 8.9 per 10,000 children (95% CI, −14.9 to 20.8). The rate of ADHD treatment was also higher among those born in August than those born in September, an absolute difference of 12.5 per 10,000 children (95% CI, 2.43 to 22.4). These differences were not observed for other month-to-month comparisons, nor were they observed in states with non-September cutoff dates for starting kindergarten. In addition, in states with a September 1 cutoff, no significant differences between August-born and September-born children were observed in rates of asthma, diabetes, or obesity. Results suggest that younger children in a school grade cohort are more likely to receive an ADHD diagnosis than their older peers because of age-based variation in behavior.

The Three Year Impact of the ACA on Disparities in Insurance Coverage
C. Courtemanche, I. Fazlul, J. Marton, B. Ukert, A. Yelowitz, D. Zapata, Health Services Research, 54, February 2019, pp. 307-16.

The impact of the Affordable Care Act (ACA) on disparities in insurance coverage after three years was examined for the ACA's three major components: Medicaid expansion, subsidized Marketplace plans, and insurance market reforms. Examining nonelderly adults in the 2011-2016 waves of the American Community Survey (ACS), the study estimated a difference-in-difference-in-differences model to separately identify the effects of the nationwide and Medicaid expansion portions of the ACA using the methodology developed in the recent ACA literature. The differences came from time, state Medicaid expansion status, and local area pre-ACA uninsured rates. In order to focus on access disparities, the sample was stratified separately by income, race/ethnicity, marital status, age, gender, and geography. After three years, the fully implemented ACA eliminated 43% of the coverage gap across income groups, with the Medicaid expansion accounting for this entire reduction. The ACA also reduced coverage disparities across racial groups by 23%, across marital status by 46%, and across age-groups by 36%, with these changes being partly attributable to both the Medicaid expansion and nationwide components of the law..

Racial and Ethnic Disparities in Medication Adherence among Privately Insured Patients in the United States
R. Xie, P. St. Clair, D. Goldman, G. Joyce, PLoS ONE, 14(2), February 14, 2019, eo212117.

This study examined the association between socioeconomic status (SES) and racial and ethnic disparities in medication adherence. Longitudinal claims data from a large US-based insurance provider (2011–2013) were linked to detailed SES information to identify patients treated with oral antidiabetic, antihypertensive, or antihyperlipidemic medications. During an average follow-up period of 2.5 years, average adherence rates of Blacks and Hispanics were at least 7.5 percentage points lower than those of Whites. While controlling for demographics, health status, out-of-pocket costs, convenience of refilling prescriptions and SES attenuated the association by 30 to 50 percent, nonetheless substantial racial disparities persisted (4.1–5.8 percentage points), particularly for asymptomatic conditions. Separating adherence among existing users from those that discontinued therapies indicates that racial/ethnic disparities in adherence reflect inconsistent pill-taking rather than differential rates of discontinuation. This highlights the importance of interventions to improve the medication adherence of existing users, particularly in treating asymptomatic conditions.

Explaining the Slowdown in Medical Spending Growth among the Elderly, 1999-2012
D. M. Cutler, K. Ghosh, K. L. Messer, T. E. Raghunathan, S. T. Stewart, A. B. Rosen, Health Affairs, 38(2), February 2019, pp. 222-9.

Trends in per capita spending for Medicare beneficiaries ages sixty-five and older in the United States from 1999–2012 were examined to determine why spending growth has been declining since around 2005. Decomposing spending by condition in the Medicare Current Beneficiary Survey, the study found that half of the spending slowdown was attributable to slower growth in spending for cardiovascular diseases, in particular due to fewer hospitalizations for acute cardiac events. Spending growth also slowed for dementia, renal and genitourinary diseases, and aftercare for people with acute illnesses. Using estimates from the medical literature of the impact of pharmaceuticals on acute disease, the authors found that roughly half of the reduction in major cardiovascular events was attributable to medications controlling cardiovascular risk factors (hypertension, hyperlipidemia, and diabetes). The results demonstrate that medically driven prevention can save money over time. Given that only 55–60 percent of people have their risk factors under control, and the possibility that other diseases can be prevented as well, the authors conclude that additional opportunities remain to lower spending through disease prevention and control.

Fiscal Policy to Improve Diets and Prevent NCDs: From Recommendations to Action
A. M. Thow, S. Downs, C. Mayes, H. Trevena, T. Waqanivalu, J. Cawley, Bulletin of the World Health Organization, 96(3), March 2018, pp. 201-10.

Factors of U.S. Hospitals Associated with Improved Profit Margins: An Observational Study
D. P. Ly, D. M. Cutler, Journal of General Internal Medicine, 33(7), July 2018, pp. 1020-7.

Growing Number of Unsubsidized Part D Beneficiaries with Catastrophic Spending Suggests Need for an Out-Of-Pocket Cap
E. Trish, J. Xu, G. Joyce, Health Affairs, 37(7), July 2018, pp. 1048-56.

Effects of the Affordable Care Act on Health Care Access and Self-Assessed Health after Three Years
C. Courtemanche, J. Marton, B. Ukert, A. Yelowitz, D. Zapata, Inquiry: The Journal of Health Care Organization, Provision, and Financing, 55, September 2018, pp. 1-10.

Third Year of Evidence Shows Continuing Benefits of Medicaid Expansions
J. Cawley, A. Soni, K. Simon, Journal of General Internal Medicine, 33(9), September 2018, pp. 1495-7.

Generic Drug Price Hikes and Patient Out-Of-Pocket Costs for Medicare Beneficiaries
G. Joyce, L. Henkhaus, L. Gascue, J. Zissimopoulos, Health Affairs, 37(10), October 2018, pp.1578-86.

Intergenerational Transmission of Paternal Trauma among U.S. Civil War Ex-POWs
D. L. Costa, N. Yetter, H. DeSomer, Proceedings of the National Academy of Sciences, 115(44), October 2018, pp. 11215-20.

Adverse Selection into and within the Individual Health Insurance Market in California in 2014
V. Fung, C. Peitzman, J. Shi, C. Liang, W. Dow, A. Zaslavsky, B. Fireman, S. F. Derose, M. Chernew, J. P. Newhouse, J. Hsu, Health Services Research, 53(5), October 2018, pp. 3750-69.

The Association of Multiple Anti-Hypertensive Medication Classes with Alzheimer's Disease Incidence across Sex, Race and Ethnicity
D. Barthold, G. Joyce, W. Wharton, P. Kehoe, J. Zissimopoulos, PLoS ONE, 13(11), November 1, 2018, e0206705.

An Experimental Investigation of Preference Misrepresentation in the Residency Match
A. Rees-Jones, S. Skowronek, Proceedings of the National Academy of Sciences, 115(45), November 6, 2018, pp. 11471-6.

Quasi-Experimental Causality in Neuroscience and Behavioural Research
I. E. Marinescu, P. N. Lawlor, P. Konrad, K. P. Kording, Nature Human Behaviour, 2, November 2018, pp. 891–8.

The Challenge of Measuring Surgeon Spending for Payment Policies
P. VonAchen, R. A. Hayward, E. C. Norton, B. Denton, C. Ellimoottil, Annals of Surgery, 268(6), December 2018, pp. 903–7.

High-Deductible Insurance and Delay in Care for the Macrovascular Complications of Diabetes
J. F. Wharam, C. Y. Lu, F. Zhang, A. Hernandez, M. Callahan, X. Xu, J. Wallace, S. Soumerai, D. Ross-Degnan, J. P. Newhouse, Annals of Internal Medicine, 169(12), December 18, 2018, pp. 845-64.

The Contribution of New Product Entry versus Existing Product Inflation in the Rising Costs of Drugs
I. Hernandez, C. B. Good, D. M. Cutler, W. F. Gellad, N. Parekh, W. H. Shrank, Health Affairs, 38(1), January 2019, pp. 76-83.

Potential Effects of Eliminating the Individual Mandate Penalty in California: Uneven Coverage Losses and Premium Increases
V. Fung, C. Liang, J. Shi, A. Zaslavsky, W. Dow, M. Chernew, J. Newhouse, J. Hsu, Health Affairs, 38(1), January 2019, pp. 147-54.

Genetic Legacy of State Centralization in the Kuba Kingdom of the Democratic Republic of the Congo
L. van Dorp, S. Lowes, J. L. Weigel, N. Ansari-Pour, S. Lopez, J. Mendoza-Revilla, J. A. Robinson, J. Henrich, M. G. Thomas, N. Nunn, G. Hellenthal, Proceedings of the National Academy of Sciences, 116(2), January 8, 2019, pp. 593-8.

Genome-Wide Association Analyses of Risk Tolerance and Risky Behaviors in over 1 Million Individuals Identify Hundreds of Loci and Shared Genetic Influences
R. K. Linnér, P. Biroli, E. Kong, S. Fleur, W. Meddens, R. Wedow, M. A. Fontana, M. Lebreton,... J. Gratten, J. J. Lee, D. Cesarini, D. J. Benjamin, P. Koellinger, J. P. Beauchamp, Nature Genetics, January 2019, pp. 245-57

Hospital Prices Grew Substantially Faster Than Physician Prices for Hospital-Based Care in 2007-2014
Z. Cooper, S. Craig, M. Gaynor, N. J. Harish, H. M. Krumholz, J. Van Reenen, Health Affairs, 39(2), February 2019, pp. 184-9.

Variation in Health Spending for the Privately Insured from 2007 to 2014
Z. Cooper, S. Craig, C. Gray, M. Gaynor, J. Van Reenen, Health Affairs, 38(2), February 2019, pp. 230-6.

Risk Adjustment in Medicare ACO Program Deters Coding Increases but May Lead ACOs to Drop High-Risk Beneficiaries
A. A. Markovitz, J. M. Hollingsworth, J. Z. Ayanian, E. C. Norton, N. M. Moloci, P. L. Yan, A.M. Ryan, Health Affairs, 38(2), February 2019, pp. 253–61.

Initial Opioid Prescriptions among U.S. Commercially Insured Patients, 2012–2017
W. Zhu, M. E. Chernew, T. B. Sherry, N. Maestas, New England Journal of Medicine, 380, March 2019, pp. 1043-52.