Disparities In Probability Research Articles

Structural Estimation of Kidney Transplant Candidates' Quality of Life Scores: Improving National Kidney Allocation Policy Under Endogenous Patient Choice and Geographical Sharing

We develop a data-driven framework for assessing the impact of changes to the deceased-donor kidney allocation policy taking into account the transplant candidates' (endogenous) organ acceptance behavior and sharing among different locations under UNOS' geographically tiered allocation structure. To be specific, we develop a dynamic structural model of the transplant candidates' accept/reject decisions for organ offers. Our model of the national list (and its geographic structure) can be incorporated into the Kidney Pancreas Simulation Allocation Model (KPSAM) that is used to inform policy makers. Moreover, it allows important features of the transplant system such as the degree of tissue matching, changes in the health status of the transplant candidates as they wait on the list, organ quality, geographical sharing and cold-ischemia time of the organs as well as the heterogeneity in transplant candidates' quality of life scores. Using United Network of Organ Sharing (UNOS) data on transplant candidates, donors, organ offers, and follow up results on transplant outcomes, we estimate the transplant candidates' quality of life scores on dialysis versus post transplant. Our estimates yield similar results on average to what is typically assumed in the medical literature. However, they differ significantly when patient and donor characteristics are considered. We then consider policy proposals that have been considered by UNOS. This counterfactual analysis helps assess the (unintended) consequences of such policies. We find that although the current policy increases the total number of transplants by 2.63% and total life years by 4.45%, it decreases total quality adjusted life years by 1.68%. Moreover, it increases the disparity in probability of getting a transplant for patients of different health scores by 69.3% whereas it decreases disparity across patients with different sensitization (CPRA) scores. These happen due to the current prioritization of healthier patients for kidneys of better quality. Our results reveal that geographical redistricting of the transplant system, as done for the liver allocation system, does not change the system performance significantly. Hence, it should not be implemented. However, the brevity matching policy, currently being considered by UNOS, can further increase the total number of transplants by 1.50%, and is worth considering further.

Employment and Job Benefits Among Those With Spinal Cord Dysfunction: A Comparison of People With Spinal Cord Injury and Multiple Sclerosis

Objective(1) Identify the proportion of participants with spinal cord dysfunction (SCD) reporting each of 10 job benefits and compare the proportions between participants with spinal cord injury (SCI) and multiple sclerosis (MS); and (2) examine if diagnostic criteria, demographics, education level, and functional limitations are associated with the number of job benefits received. DesignEconometric modeling of cross-sectional data using a 2-step data analytic model of employment and job benefits. SettingMedical university in the southeastern United States. ParticipantsParticipants (N=2624) were identified from the southeastern United States. After eliminating those age 65 and older, there were 2624 adult participants with SCD; 1234 had MS and 1390 had SCI. InterventionsNot applicable. Main Outcome MeasuresCurrent employment status; number of benefits received and specific benefits received. ResultsA greater proportion of participants with MS received benefits, with significant differences observed on all but 1 type of benefit. Among those who were employed, a greater number of benefits was associated with having MS, greater education, younger age, married or in an unmarried couple, and not having functional restrictions with cognition, doing errands, or shopping alone in the community, and walking. ConclusionsEmployed participants with MS were more likely to receive job benefits, indicative of a higher quality of employment, compared to participants with SCI. Employment without benefits is a form of underemployment that disproportionately affects individuals with many of the same characteristics that initially lead to disparities in probability of gainful employment.

Disparity in Neurotransmitter Release Probability among Competing Inputs during Neuromuscular Synapse Elimination

Competition among the several motor axons transiently innervating neonatal muscle fibers results in an increasing disparity in the quantal content and synaptic territory of each competitor, culminating in the permanent loss of all but one axon from neuromuscular junctions. We asked whether differences in the probability of neurotransmitter release also contribute to the increasing disparity in quantal content among competing inputs, and when in the process of competition changes in release probability become apparent. To address these questions, intracellular recordings were made from dually innervated neonatal mouse soleus muscle fibers, and quantal content and paired-pulse facilitation were evaluated for each input. At short interpulse intervals, paired-pulse facilitation was significantly higher for the weaker input with the smaller quantal content than the stronger input with the larger quantal content. Because neurotransmitter release probability across all release sites is inversely related to the extent of facilitation observed after paired-pulse stimulation, this result suggests that release probability is lower for weak compared with strong inputs innervating the same junction. A disparity in the probability of neurotransmitter release thus contributes to the disparity in quantal content that occurs during synaptic competition. Together, this work suggests that an input incapable of sustaining a high release probability may be at a competitive disadvantage for synaptic maintenance.