Publications

``Barriers to Timely Presentation of Patients with Surgical Conditions at Tamale Teaching Hospital in Northern Ghana," World Journal of Surgery. 2018: https://doi.org/10.1007/s00268-018-4800-x

"The Use of Mesh for Inguinal Hernia Repair in Northern Ghana." Journal of Surgical Research, 2018; 230: 137-142.

``Local anesthesia underutilized for inguinal hernia repair in northern Ghana," PLoS ONE 13(11): e0206465. https://doi. org/10.1371/journal.pone.0206465

"Coagulation Laboratory Testing Is Predictive of Wound Complications Following Microdiscectomy." Global Spine Journal, 2018: DOI: 10.1177/2192568218764677

Working Papers

Minimum Wage and Infant Mortality: Estimates Using Contiguous County-pairs

Job Market Paper

Interest in the non-economic impact of minimum wage laws have led to a growing literature examining how population health measures respond to state minimum wage increases in the US. These studies rely on the canonical two-way fixed effect estimator, which is an unreliable method to infer causal effects with spatially heterogeneous populations. In this paper, I study the impact of minimum wage differences across states and within-state ordinances on infant mortality rates. I isolate the causal effect of the minimum wage by employing a spatial regression discontinuity design using contiguous counties in different states that share a common state border as local treatment and control populations. I find that a 10 percent increase in local cost-of-living adjusted minimum wage reduces infant mortality rates by 3.2 percent among lower-educated mothers--a group more likely affected by minimum wage changes. I find that reductions in infant mortality is concentrated in the post-neonatal period. I also demonstrate that the traditional empirical approach employed in this literature will produce lower estimates of the health impact of the minimum wage. My findings provide robust evidence that minimum wage increases are causally linked with improved infant health.


Subjective Life Expectancy as a Source of Health Disparities?

A large volume of literature links social and economic factors with mortality and life expectancy. This essay examines to what extent these socio-economic factors, specifically income, impact subjective life expectancy (SLE) or an individual’s belief in surviving to a certain age. I first develop a model to describe how SLE may play an important role in linking wage increases to favorable health behavior by making future time costs of adverse health events binding. I then estimate a heterogeneous choice proportional odds model using previously unexplored data from the Federal Reserve's 2013 Survey of Household Economics and Decision-making (SHED) to study this relationship. I find that Income and higher education is strongly associated with improved confidence in survival to age 75. I also find that periods of unemployment, disability, divorce, negative life event associated with the great recession were negatively associated with SLE. My study contributes to the health disparities literature by providing evidence for a new channel connecting socio-economic factors and health outcomes. 


Provider Practice Competition and Adoption of Medicare's Oncology Care Model

There is concern that the Oncology Care Model (OCM), a new and voluntary bundled payment program, may incentivize mergers and acquisitions leading to reduced competition and price increases. However, little is known about factor that determine adoption of OCM. We used data from the CMS National Provider Identifier (NPI) Registry and the Physician Compare National Downloadable File (PCF) to study the relationship between OCM adoption and physician-defined Herfindahl-Hirschman Index (HHI), a measure of competition, for medical oncology practices with providers that billed Medicare in 2015. We found that adoption was higher in markets with greater competition with a 15.7 percent difference in predicted probability of adoption comparing the interquartile range of HHI. However, in markets with at least one OCM adopter, less competition was associated with an increase in the proportion of practices adopting OCM. Average practice size and number of physician practices in a healthcare market were positively associated with OCM adoption. Our findings argue for increased monitoring of market-level changes amongst OCM adopters to ensure that the benefits outweigh the potential impact of reducing competition.


Cost-effectiveness Analysis of Screening and Drug Therapy for Infantile-onset Spinal Muscular Atrophy?

Background: Spinal Muscular Atrophy (SMA), an autosomal neuromuscular disorder, is one of the leading genetic contributors of infant mortality. Infantile onset SMA is the most severe type of SMA and the median survival time for children with this condition is typically less than 2 years of age. Currently, only a handful of states screen for SMA as part of their universal newborn screening program. However, with introduction of new treatment options, SMA is under consideration for the Recommended Uniform Screening Panel’s (RUSP) list of disorders to be screened at birth. This study estimates the cost-effectiveness of universal newborn screening and treatment of infantile onset SMA.

Methods: We developed a decision analytic Markov model to estimate the expected costs and health benefits of infantile onset SMA with a time horizon of 2.5 years and a hypothetical population of 100,000 live births. Model inputs were derived from the literature with the main treatment related parameters derived from the recently published ENDEAR trial that compared the outcomes of SMA treatment with Nusinersen versus a sham control. Primary outcomes were costs per event-free life years saved with universal newborn screening and drug therapy as compared to drug therapy without screening and no treatment nor screening.

Results: The estimated Incremental Cost-effectiveness Ratio (ICER) for Nusinersen drug therapy without screening was $508,481 per event-free LY saved and $522,118 per event-free QALY saved. ICERs for Screening newborns along with treatment was $193,867 per event-free LY saved and $199,510 per event-free QALY saved. Our estimates are greater than standard willingness-to-pay (WTP) thresholds. However, we find that at a per dose price of $32,250, Screening and treatment is a cost-effective strategy given a WTP threshold of $50,000.

Conclusion: This study provides the first estimates for the cost-effectiveness of SMA drug therapy treatment with universal newborn screening. We find that the current per dose price of drug therapy is too high for screening and treatment to be cost-effective, but recommend multiple price points for different WTP thresholds in which drug therapy and screening will be cost-effective.


Cost effectiveness of current and potential serum based colorectal screening strategies: can a serum based test do better?

Background:Despite efficacy of colorectal cancer (CRC) screening, recent trends in screening rates have not improved. Furthermore, national society recommendations have not prioritized a single screening modality. Both flexible sigmoidoscopy (Flex-Sig) and guaiac fecal occult blood test (gFOBT)) have been recommended. Studies suggest that noninvasive tests may improve screening rates, however, compliance remains modest for such tests. A recent study found that health system transition from gFOBT to a fecal immunochemical test (FIT) moderately improved test compliance rates. However, FIT is an expensive substitute for gFOBT and sensitivity of fecal based tests for precursor lesions in the colon remain inferior to structural examinations. Serum-based blood tests (SBT) may provide higher compliance rates, but necessary accuracy for such a test to be a dominant or cost-effective screening strategy over current recommendations have not been determined. This study analyzed the cost-effectiveness of multiple CRC screening strategies and estimated minimum test characteristics of a hypothetical SBT to be a preferred screening strategy over current modalities.

Methods:A Markov microsimulation model was developed to analyze the costs and effects, (quality-adjusted life-years, QALYs) of CRC screening following a hypothetical cohort of 10,000 individuals at age 50 until death. Our model considered three strategies: 1) initial colonoscopy followed by Flex-Sig every 5 years, 2) initial colonoscopy with yearly gFOBT, and 3) initial colonoscopy with yearly FIT. An initial colonoscopy with a hypothetical yearly SBT was also examined at a range of test sensitivities. A long-term payer perspective was assumed for professional and facility costs and lifetime costs of cancer treatment. Model probabilities and utility values were obtained from the literature or calculated from National Vital Statistics Reports. 

Results:Annual gFOBT was the least costly strategy ($3,242) while annual FIT was eliminated through extended dominance. Flex-Sig was the costliest strategy at $4,667 but had the highest expected QALYs at 19.68. The incremental cost-effectiveness ratio (ICER) of Flex-Sig relative to gFOBT was $35,615. Our secondary analysis demonstrated that a minimum joint sensitivity of 70% and 60% is required for an SBT at 80% and 100% compliance rates, respectively, to achieve extended dominance of both Flex-Sig and FIT by SBT and gFOBT. ICER’s of SBT ranged from $12,984 to $4,779 in these sensitivity ranges compared to gFOBT with expected QALYs as high as 19.96. Total individual costs in the model varied from $365 to $111,535.

Conclusion:With improved sensitivity and high compliance rates, annual screening for CRC via a non-invasive SBT is a cost-effective approach compared to structural examinations and currently recommended gFOBT and FIT.