All Publications

  • A New Type 2 Diabetes Microsimulation Model to Estimate Long-term Health Outcomes, Costs, and Cost-Effectiveness. Value in health : the journal of the International Society for Pharmacoeconomics and Outcomes Research Hoerger, T. J., Hilscher, R., Neuwahl, S., Kaufmann, M. B., Shao, H., Laxy, M., Cheng, Y. J., Benoit, S., Chen, H., Anderson, A., Craven, T., Yang, W., Cintina, I., Staimez, L., Zhang, P. 2023


    To develop a microsimulation model to estimate the health effects, costs, and cost-effectiveness of public health and clinical interventions for preventing/managing type 2 diabetes.We combined newly developed equations for complications, mortality, risk factor progression, patient utility, and cost-all based on U.S. studies-in a microsimulation model. We performed internal and external validation of the model. To demonstrate the model's utility, we predicted remaining life-years, quality-adjusted life-years (QALYs), and lifetime medical cost for a representative cohort of 10,000 U.S. adults with type 2 diabetes. We then estimated the cost-effectiveness of reducing HbA1c from 9% to 7% among adults with type 2 diabetes, using low-cost, generic, oral medications.The model performed well in internal validation; the average absolute difference between simulated and observed incidence for 17 complications was less than 8%. In external validation, the model was better at predicting outcomes in clinical trials than in observational studies. The cohort of U.S. adults with type 2 diabetes was projected to have an average of 19.95 remaining life-years (from mean age 61), incur $187,729 in discounted medical costs, and accrue 8.79 discounted QALYs. The intervention to reduce HbA1c increased medical costs by $1,256 and QALYs by 0.39, yielding an incremental cost-effectiveness ratio of $9,103 per QALY.Using equations exclusively derived from U.S. studies, this new microsimulation model achieves good prediction accuracy in U.S.The model can be used to estimate the long-term health impact, costs, and cost-effectiveness of interventions for type 2 diabetes in the United States.

    View details for DOI 10.1016/j.jval.2023.05.013

    View details for PubMedID 37236396

  • Deceased Donor Kidney Transplantation for Older Transplant Candidates: A New Microsimulation Model for Determining Risks and Benefits. Medical decision making : an international journal of the Society for Medical Decision Making Kaufmann, M. B., Tan, J. C., Chertow, G. M., Goldhaber-Fiebert, J. D. 2023: 272989X231172169


    Under the current US kidney allocation system, older candidates receive a disproportionately small share of deceased donor kidneys despite a reserve of potentially usable kidneys that could shorten their wait times. To consider potential health gains from increasing access to kidneys for these candidates, we developed and calibrated a microsimulation model of the transplantation process and long-term outcomes for older deceased donor kidney transplant candidates.We estimated risk equations for transplant outcomes using the Scientific Registry of Transplant Recipients (SRTR), which contains data on all US transplants (2010-2019). A microsimulation model combined these equations to account for competing events. We calibrated the model to key transplant outcomes and used acceptance sampling, retaining the best-fitting 100 parameter sets. We then examined life expectancy gains from allocating kidneys even of lower quality across patient subgroups defined by age and designated race/ethnicity.The best-fitting 100 parameter sets (among 4,000,000 sampled) enabled our model to closely match key transplant outcomes. The model demonstrated clear survival benefits for those who receive a deceased donor kidney, even a lower quality one, compared with remaining on the waitlist where there is a risk of removal. The expected gain in survival from receiving a lower quality donor kidney was consistent gains across age and race/ethnic subgroups.Limited available data on socioeconomic factors.Our microsimulation model accurately replicates a range of key kidney transplant outcomes among older candidates and demonstrates that older candidates may derive substantial benefits from transplantation with lower quality kidneys. This model can be used to evaluate policies that have been proposed to address concerns that the current system disincentivizes deceased donor transplants for older patients.The microsimulation model was consistent with the data after calibration and accurately simulated the transplantation process for older deceased donor kidney transplant candidates.There are clear survival benefits for older transplant candidates who receive deceased donor kidneys, even lower quality ones, compared with remaining on the waitlist.This model can be used to evaluate policies aimed at increasing transplantation among older candidates.

    View details for DOI 10.1177/0272989X231172169

    View details for PubMedID 37170943

  • Racial Disparities in Pediatric Kidney Transplantation under the New Kidney Allocation System in the United States. Clinical journal of the American Society of Nephrology : CJASN Krissberg, J., Kaufmann, M., Gupta, A., Bendavid, E., Stedman, M., Cheng, X., Tan, J., Grimm, P., Chaudhuri, A. 2021


    Background and Objectives: In December 2014, the Kidney Allocation System (KAS) was implemented to improve equity in access to transplantation, but preliminary studies in children show mixed results. Thus, we aimed to assess how the 2014 KAS policy change affected racial/ethnic disparities in pediatric kidney transplantation access and related outcomes. Design, setting, participants, and measurements: A retrospective cohort study of children <18 years of age active on the kidney transplant list from 2008 to 2019 using the Scientific Registry of Transplant Recipients. Log-logistic accelerated failure time models were used to determine time from first activation on the transplant list and time on dialysis to deceased-donor transplant, each with KAS era or race/ethnicity as the exposure of interest. We used logistic regression to assess odds of delayed graft function. Log-rank tests assessed time to graft loss within racial/ethnic groups across KAS eras. Results: All children experienced longer wait times from activation to transplantation post-KAS. In univariable analysis, Black or Hispanic children or other children of color experienced longer times from activation to transplant compared to White children in the both eras; this finding was largely attenuated after multivariable analysis (time ratio 1.16, (95% CI 1.01-1.32); 1.13 (1.00-1.28); 1.17 (0.96-1.41) post-KAS, respectively). Multivariable analysis also showed that racial/ethnic disparities in time from dialysis initiation to transplantation in the pre-KAS era was mitigated in the post-KAS era. There were no disparities in odds of delayed graft function. Black or Hispanic children experienced longer times with a functioning graft in the post-KAS era. Conclusions: No racial/ethnic disparities from activation to deceased donor transplantation were seen before or after implementation of KAS in multivariable analysis, while time on dialysis to transplantation and odds of short-term graft loss improved in equity after KAS, without compromising disparities in delayed graft function.

    View details for DOI 10.2215/CJN.06740521

    View details for PubMedID 34670797

  • Immunosuppression Considerations for Older Kidney Transplant Recipients. Current transplantation reports Cheungpasitporn, W., Lentine, K. L., Tan, J. C., Kaufmann, M., Caliskan, Y., Bunnapradist, S., Lam, N. N., Schnitzler, M., Axelrod, D. A. 2021; 8 (2): 100-110


    While kidney transplantation improves the long-term survival of the majority of patients with end-stage kidney disease (ESKD), age-related immune dysfunction and associated comorbidities make older transplant recipients more susceptible to complications related to immunosuppression. In this review, we discuss appropriate management of immunosuppressive agents in older adults to minimize adverse events, avoid acute rejection, and maximize patient and graft survival.Physiological changes associated with senescence can impact drug metabolism and increase the risk of posttransplant infection and malignancy. Clinical trials assessing the safety and efficacy of immunosuppressive agents in older adults are lacking. Recent findings from U.S. transplant registry-based studies suggest that risk-adjusted death-censored graft failure is higher among older patients who received antimetabolite avoidance, mammalian target of rapamycin inhibitor (mTORi)-based, and cyclosporine-based regimens. Observational data suggest that risk-adjusted mortality may be increased in older patients who receive mTORi-based and cyclosporine-based regimens but lower in those managed with T-cell induction and maintenance steroid avoidance/withdrawal.Tailored immunosuppression management to improve patient and graft survival in older transplant recipients is an important goal of personalized medicine. Lower intensity immunosuppression, such as steroid-sparing regimens, appear beneficial whereas mTORi- and cyclosporine-based maintenance are associated with greater potential for adverse effects. Prospective clinical trials to assess the safety and efficacy of immunosuppression agents in older recipients are urgently needed.

    View details for DOI 10.1007/s40472-021-00321-6

    View details for PubMedID 34211822

    View details for PubMedCentralID PMC8244945

  • Immunosuppression Considerations for Older Kidney Transplant Recipients CURRENT TRANSPLANTATION REPORTS Cheungpasitporn, W., Lentine, K. L., Tan, J. C., Kaufmann, M., Caliskan, Y., Bunnapradist, S., Lam, N. N., Schnitzler, M., Axelrod, D. A. 2021