Search

Your search keyword '"Kelz, Rachel R."' showing total 1,396 results
Start Over Author "Kelz, Rachel R."
1,396 results on '"Kelz, Rachel R."'

4. The Blue Ribbon Committee II Report and Recommendations on Surgical Education and Training in the United States: 2024

Author

Stain, Steven C., Ellison, E. Christopher, Farmer, Diana L., Flynn, Timothy C., Freischlag, Julie A., Matthews, Jeffrey B., Newman, Rachel Williams, Chen, Xiaodong, Stefanidis, Dimitrios, Britt, L.D., Buyske, Jo, Fisher, Karen, Sachdeva, Ajit K., Turner, Patricia L., Flynn, Timothy C., Bass, Barbara L., Brennan, Murray F., Debas, Haile T., Freischlag, Julie A., Jones, R. Scott, Malangoni, Mark A., Pellegrini, Carlos A., Sachdeva, Ajit K., Turner, Patricia L., Warshaw, Andrew L., Welling, Richard E., Zinner, Michael J., Alseidi, Adnan A., Ford, Henri R., Craver, H. William, Dennis, Andrew J., Fingeret, Abbey, Fried, Gerald M., Mason, Bonnie Simpson, Sudan, Ranjan, Yang, Stephen C., Conrad-Schnetz, Kristen, Terhune, Kyla P., Johnson, Wali R., Jenkins Turner, Megan E., Prabhu, Ajita S., Mason, Bonnie Simpson, Brasel, Karen J., Mellinger, John D., Elster, Eric A., Fried, Gerald M., Hashimoto, Daniel A., Jarman, Benjamin T., Joshi, Amit R. T., Kelz, Rachel R., Lindeman, Brenessa M., Pugh, Carla M., Reznick, Richard K., Freischlag, Julie A., Klingensmith, Mary E., Berry, Cherisse D., Cooke, David T., Fisher, Karen, Minter, Rebecca M., Phillips, Linda G., Sidawy, Anton N., Farmer, Diana L., Damewood, Richard B., Freischlag, Julie A., Mansour, M. Ashraf, Michelassi, Fabrizio, Shabahang, Mohsen M., Sharp, Kenneth, Hawn, Mary T., Matthews, Jeffrey B., Bumgardner, Ginny L., Economou, James S., Itani, Kamal M. F., Kelz, Rachel R., Tracy, Thomas F., Jr, Zeiger, Martha A., Fried, Gerald M., Pugh, Carla M., Greenberg, Caprice C., Hashimoto, Daniel A., Paige, John T., Telem, Dana A., Varas, Julian E., Chen, Xiaodong, Stefanidis, Dimitrios, Ellison, E. Christopher, Stain, Steven C., Britt, L.D., Buyske, Jo, Karen Fisher, JD, Sachdeva, Ajit K., Turner, Patricia L., Blair, Patrice Gabler, Bura, Connie, Lupi, Linda K., McGory, Deirdre M., Newman, Rachel Williams, and Schmitt, Peter J.

Published
2024
Full Text
View/download PDF

14. Profiling Compliers in Instrumental Variables Designs

Author

Hangartner, Dominik, Marbach, Moritz, Henckel, Leonard, Maathuis, Marloes H., Kelz, Rachel R., and Keele, Luke

Subjects
Statistics - Methodology
Abstract

Instrumental variable (IV) analyses are becoming common in health services research and epidemiology. IV analyses can be used both to analyze randomized trials with noncompliance and as a form of natural experiment. In these analyses, investigators often adopt a monotonicity assumption, which implies that the relevant effect only applies to a subset of the study population known as compliers. Since the estimated effect is not the average treatment effect of the study population, it is important to compare the characteristics of compliers and non-compliers. Profiling compliers and non-compliers is necessary to understand what subpopulation the researcher is making inferences about, and an important first step in evaluating the external validity (or lack thereof) of the IV estimate for compliers. Here, we discuss the assumptions necessary for profiling, which are weaker than the assumptions necessary for identifying the local average treatment effect if the instrument is randomly assigned. We then outline a simple and general method to characterize compliers and noncompliers using baseline covariates. Next, we extend current methods by deriving standard errors for these estimates. We demonstrate these methods using an IV known as tendency to operate (TTO) from health services research.

Published
2021

31. A National Comparison of Operative Outcomes of New and Experienced Surgeons.

Author

Kelz, Rachel R, Sellers, Morgan M, Niknam, Bijan A, Sharpe, James E, Rosenbaum, Paul R, Hill, Alexander S, Zhou, Hong, Hochman, Lauren L, Bilimoria, Karl Y, Itani, Kamal, Romano, Patrick S, and Silber, Jeffrey H

Subjects
Biomedical and Clinical Sciences, Clinical Sciences, Health Services, Aging, Clinical Research, 6.4 Surgery, Evaluation of treatments and therapeutic interventions, Good Health and Well Being, Aged, Clinical Competence, Female, Humans, Length of Stay, Male, Medicare, Outcome Assessment, Health Care, Postoperative Complications, Surgical Procedures, Operative, United States, new surgeon outcomes, surgeon experience, surgical outcomes, Medical and Health Sciences, Surgery, Clinical sciences
Abstract

ObjectiveTo determine whether outcomes achieved by new surgeons are attributable to inexperience or to differences in the context in which care is delivered and patient complexity.BackgroundAlthough prior studies suggest that new surgeon outcomes are worse than those of experienced surgeons, factors that underlie these phenomena are poorly understood.MethodsA nationwide observational tapered matching study of outcomes of Medicare patients treated by new and experienced surgeons in 1221 US hospitals (2009-2013). The primary outcome studied is 30-day mortality. Secondary outcomes were examined.ResultsIn total, 694,165 patients treated by 8503 experienced surgeons were matched to 68,036 patients treated by 2119 new surgeons working in the same hospitals. New surgeons' patients were older (25.8% aged ≥85 vs 16.3%,P

Published
2021

36. Biased Encouragements and Heterogeneous Effects in an Instrumental Variable Study of Emergency General Surgical Outcomes

Author

Fogarty, Colin B., Lee, Kwonsang, Kelz, Rachel R., and Keele, Luke J.

Subjects
Statistics - Applications
Abstract

We investigate the efficacy of surgical versus non-surgical management for two gastrointestinal conditions, colitis and diverticulitis, using observational data. We deploy an instrumental variable design with surgeons' tendencies to operate as an instrument. Assuming instrument validity, we find that non-surgical alternatives can reduce both hospital length of stay and the risk of complications, with estimated effects larger for septic patients than for non-septic patients. The validity of our instrument is plausible but not ironclad, necessitating a sensitivity analysis. Existing sensitivity analyses for IV designs assume effect homogeneity, unlikely to hold here because of patient-specific physiology. We develop a new sensitivity analysis that accommodates arbitrary effect heterogeneity and exploits components explainable by observed features. We find that the results for non-septic patients prove more robust to hidden bias despite having smaller estimated effects. For non-septic patients, two individuals with identical observed characteristics would have to differ in their odds of assignment to a high tendency to operate surgeon by a factor of 2.34 to overturn our finding of a benefit for non-surgical management in reducing length of stay. For septic patients, this value is only 1.64. Simulations illustrate that this phenomenon may be explained by differences in within-group heterogeneity.

Published
2019

37. Optimal Tradeoffs in Matched Designs Comparing US-Trained and Internationally Trained Surgeons

Author

Pimentel, Samuel D and Kelz, Rachel R

Subjects
Statistics, Econometrics, Demography, Statistics & Probability
Abstract

Does receiving a medical education outside the United States impact a surgeon’s performance? We study this question by matching operations performed by internationally trained surgeons to those performed by US-trained surgeons in reanalysis of a large health outcomes study. An effective matched design must achieve several goals, including balancing covariate distributions marginally, ensuring units within individual pairs have similar values on key covariates, and using a sufficiently large sample from the raw data. Yet in our study, optimizing some of these goals forces less desirable results on others. We address such tradeoffs from a multi-objective optimization perspective by creating matched designs that are Pareto optimal with respect to two goals. We provide general tools for generating representative subsets of Pareto optimal solution sets and articulate how they can be used to improve decision-making in observational study design. In the motivating surgical outcomes study, formulating a multi-objective version of the problem helps us balance an important variable without sacrificing two other design goals, average closeness of matched pairs on a multivariate distance and size of the final matched sample. Supplementary materials for this article, including a standardized description of the materials available for reproducing the work, are available as an online supplement.

Published
2020

38. Duty Hour Reform and the Outcomes of Patients Treated by New Surgeons.

Author

Kelz, Rachel R, Niknam, Bijan A, Sellers, Morgan M, Sharpe, James E, Rosenbaum, Paul R, Hill, Alexander S, Zhou, Hong, Hochman, Lauren L, Bilimoria, Karl Y, Itani, Kamal, Romano, Patrick S, and Silber, Jeffrey H

Subjects
Aging, Clinical Research, Good Health and Well Being, Algorithms, Clinical Competence, Education, Medical, Graduate, Female, Hospital Mortality, Humans, Internship and Residency, Male, Medicare, Personnel Staffing and Scheduling, Surgical Procedures, Operative, United States, Work Schedule Tolerance, duty hour reform, surgical education, surgical outcomes, Medical and Health Sciences, Surgery
Abstract

ObjectiveThe aim of the study was to address the controversy surrounding the effects of duty hour reform on new surgeon performance, we analyzed patients treated by new surgeons following the transition to independent practice.Summary background dataIn 2003, duty hour reform affected all US surgical training programs. Its impact on the performance of new surgeons remains unstudied.MethodsWe studied 30-day mortality among 1,483,074 Medicare beneficiaries undergoing general and orthopedic operations between 1999 and 2003 ("traditional" era) and 2009 and 2013 ("modern" era). The operations were performed by 2762 new surgeons trained before the reform, 2119 new surgeons trained following reform and 15,041 experienced surgeons. We used a difference-in-differences analysis comparing outcomes in matched patients treated by new versus experienced surgeons within each era, controlling for the hospital, operation, and patient risk factors.ResultsTraditional era odds of 30-day mortality among matched patients treated by new versus experienced surgeons were significantly elevated [odds ratio (OR) 1.13; 95% confidence interval (CI) (1.05, 1.22), P < 0.001). The modern era elevated odds of mortality were not significant [OR 1.06; 95% CI (0.97-1.16), P = 0.239]. Relative performance of new and experienced surgeons with respect to 30-day mortality did not appear to change from the traditional era to the modern era [OR 0.93; 95% CI (0.83-1.05), P = 0.233]. There were statistically significant adverse changes over time in relative performance to experienced surgeons in prolonged length of stay [OR 1.08; 95% CI (1.02-1.15), P = 0.015], anesthesia time [9 min; 95% CI (8-10), P < 0.001], and costs [255USD; 95% CI (2-508), P = 0.049].ConclusionsDuty hour reform showed no significant effect on 30-day mortality achieved by new surgeons compared to their more experienced colleagues. Patients of new surgeons, however, trained after duty hour reform displayed some increases in the resources needed for their care.

Published
2020

40. Contributors

Author

Aggarwal, Geeta, primary, Andukuri, Venkata, additional, Arnold, Susan LaFollette, additional, Arriaga, Alexander F., additional, Bader, Angela M., additional, Balfour, Angie, additional, Berger, Elizabeth R., additional, Berlin, Nicholas L., additional, Blitz, Jeanna D., additional, Booth, Alexander, additional, Botwinick, Laura K., additional, Bozic, Kevin, additional, Buehler, Kate, additional, Chappell, Desiree, additional, Chen, Yun-Yun K., additional, Chereshneva, Maria, additional, Clapp, Justin T., additional, Cloyd, Benjamin H., additional, Cruikshanks, Claire, additional, Dauw, Casey A., additional, Dhesi, Jugdeep, additional, DiBianco, John Michael, additional, Dixon-Woods, Mary, additional, Duffy, Caoimhe C., additional, Edwards, Angela F., additional, Edwards, Kylie-Ellen, additional, El-Ghazali, Sally, additional, Englesbe, Michael, additional, Esper, Stephen A., additional, Falk, Scott, additional, Fischer, Chelsea P., additional, Fleisher, Lee A., additional, Fogerty, Robert L., additional, Fowler, Aidan, additional, Franz, Amber, additional, Ghani, Khurshid R., additional, Grocott, Michael P.W., additional, Gulotta, Lawrence V., additional, Hallway, Alexander, additional, Harpe-Bates, Jennifer, additional, Healey, Frances, additional, Azad, Kaveh Houshmand, additional, Howard, Ryan, additional, Incorvia, Joseph, additional, Jackiewicz, Thomas E., additional, Janda, Allison, additional, Johnson, Emily H., additional, Johnston, Carolyn, additional, Jordan, Lesley, additional, Kelz, Rachel R., additional, Khan, Maria, additional, Kheterpal, Sachin, additional, King, Christopher J., additional, Ko, Clifford Y., additional, Lane-Fall, Meghan B., additional, Lee, Thomas H., additional, Levett, Denny Z.H., additional, Lin, Della M., additional, Lloyd, Robert, additional, Lockett, Mark, additional, Low, Daniel, additional, Mahajan, Aman, additional, Mainey, Chris, additional, Manning, Michael W., additional, Martin, Graham P., additional, Martin, Lynn D., additional, Mathis, Michael, additional, McCulloch, Peter, additional, Moonesinghe, S. Ramani, additional, Murray, Dave, additional, Myles, Paul S., additional, Mythen, Monty G., additional, Odell, Wendy, additional, Offodile, Anaeze C., additional, Parry, Gareth, additional, Partridge, Judith, additional, Peden, Carol J., additional, Quiney, Nial, additional, Ragheb, Jacqueline W., additional, Raper, Steven E., additional, Rogerson, Andrew, additional, Rooney, Kevin, additional, Roper, Madeleine, additional, Santhirapala, Ramai, additional, Scott, Michael, additional, Shah, Nirav, additional, Singleton, Georgina F., additional, Soar, Harry, additional, Spencer, Paula, additional, Stephens, Timothy J., additional, Stevens, Emma, additional, Sweitzer, BobbieJean, additional, Tong, Jason, additional, Tung, Alan, additional, Vetter, Thomas R., additional, Vlisides, Phillip E., additional, Wain, Hester, additional, Wick, Elizabeth C., additional, Wu, Christopher L., additional, Wyatt, Ronald, additional, and YaDeau, Jacques T., additional

Published
2023
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results