Jun 04 - Jun 04
2018
Mon - Mon

Help the Biostatistician! What You Need to Know About Estimating Power Calculations and Sample Size

Speaker

Amber Trickey
Casual - Non-Exempt, Stanford-Surgery Policy Improvement Research and Education Center
atrickey@stanford.edu

Bio

Amber W. Trickey, PhD, MS, CPH, is a health services biostatistician working with the S-SPIRE Center. She supports multidisciplinary teams in research design, implementation, and analysis. Dr. Trickey obtained degrees in epidemiology and biostatistics, and certifications in public health and SAS data analysis. She has evaluated data quality in surgical and trauma care, supported multiple clinical trials, and led data validation studies using the ACS-NSQIP surgical registry and administrative claims. Dr. Trickey has contributed to public and private grants on surgical safety, healthcare quality metrics, simulation-based training, team communication, error disclosure, and emergency services.

Publications

  • Disparities in Access, Quality, and Clinical Outcome for Latino Californians with Colon Cancer. Annals of surgery Dawes, A. J., Rajasekar, G., Arnow, K. D., Trickey, A. W., Harris, A. H., Morris, A. M., Wagner, T. H. 2024

    Abstract

    OBJECTIVE: To compare access, quality, and clinical outcomes between Latino and non-Latino White Californians with colon cancer.SUMMARY BACKGROUND DATA: Racial and ethnic disparities in cancer care remain understudied, particularly among patients who identify as Latino. Exploring potential mechanisms, including differential utilization of high-volume hospitals, is an essential first step to designing evidence-based policy solutions.METHODS: We identified all adults diagnosed with colon cancer between January 1, 2010 and December 31, 2020 from a statewide cancer registry linked to hospital administrative records. We compared survival, access (stage at diagnosis, receipt of surgical care, treatment at a high-volume hospital), and quality of care (receipt of adjuvant chemotherapy, adequacy of lymph node resection) between patients who identified as Latino and as non-Latino White.RESULTS: 75,543 patients met inclusion criteria, including 16,071 patients who identified as Latino (21.3%). Latino patients were significantly less likely to undergo definitive surgical resection (marginal difference [MD] -0.72 percentage points, 95% CI -1.19,-0.26), have an operation in a timely fashion (MD -3.24 percentage points, 95% CI -4.16,-2.32), or have an adequate lymphadenectomy (MD -2.85 percentage points, 95% CI -3.59,-2.12) even after adjustment for clinical and sociodemographic factors. Latino patients treated at high-volume hospitals were significantly less likely to die and more likely to meet access and quality metrics.CONCLUSIONS: Latino colon cancer patients experienced delays, segregation, and lower receipt of recommended care. Hospital-level colectomy volume appears to be strongly associated with access, quality, and survival--especially for patients who identify as Latino--suggesting that directing at-risk cancer patients to high-volume hospitals may improve health equity.

    View details for DOI 10.1097/SLA.0000000000006251

    View details for PubMedID 38407273

  • Disparities in access to high-volume parathyroid surgeons in the United States: A call to action. Surgery Wright, K., Squires, S., Cisco, R., Trickey, A., Kebebew, E., Suh, I., Seib, C. D. 2023

    Abstract

    Parathyroidectomy by a high-volume surgeon is associated with a reduced risk of perioperative complications and of failure to cure primary and secondary hyperparathyroidism. There are limited data on disparities in access to high-volume parathyroid surgeons in the United States.We used publicly available 2019 Medicare Provider Utilization and Payment data to identify all surgeons who performed >10 parathyroidectomies for Medicare fee-for-service beneficiaries, anticipating that fee-for-service beneficiaries likely represent only a subset of their high-volume practices. High-volume parathyroid surgeon characteristics and geographic distribution were evaluated. Inequality in the distribution of surgeons was measured by the Gini coefficient. The association between neighborhood disadvantage, based on the Area Deprivation Index, and proximity to high-volume parathyroid surgeons was evaluated using a one-way analysis of variance with Bonferroni-corrected pairwise comparisons. A sensitivity analysis was performed restricting to high-volume parathyroid surgeons within each hospital referral region, evidence-based regional markets for tertiary medical care.We identified 445 high-volume parathyroid surgeons who met inclusion criteria with >10 parathyroidectomies for Medicare fee-for-service beneficiaries. High-volume parathyroid surgeons were 71% male sex, and 59.8% were general surgeons. High-volume parathyroid surgeons were more likely to practice in a Metropolitan Statistical Area with a population >1 million than in less populous metropolitan or rural areas. The number of high-volume parathyroid surgeons per 100,000 fee-for-service Medicare beneficiaries in the 53 most populous Metropolitan Statistical Areas ranged from 0 to 4.94, with the highest density identified in Salt Lake City, Utah. In 2019, 50% of parathyroidectomies performed by high-volume parathyroid surgeons were performed by 20% of surgeons in this group, suggesting unequal distribution of surgical care (Gini coefficient 0.41). Patients in disadvantaged neighborhoods were farther from high-volume parathyroid surgeons than those in advantaged neighborhoods (median distance: disadvantaged 27.8 miles, partially disadvantaged 20.7 miles, partially advantaged 12.1 miles, advantaged 8.4 miles; P < .001). This association was also shown in the analysis of distance to high-volume parathyroid surgeons within the hospital referral region (P < .001).Older adults living in disadvantaged neighborhoods have less access to high-volume parathyroid surgeons, which may adversely affect treatment and outcomes for patients with primary and secondary hyperparathyroidism. This disparity highlights the need for actionable strategies to provide equitable access to care, including improved regionalization of high-volume parathyroid surgeon services and easing travel-related burdens for underserved patients.

    View details for DOI 10.1016/j.surg.2023.03.028

    View details for PubMedID 37940435

  • Usability of ENTRUST as an Assessment Tool for Entrustable Professional Activities (EPAs): A Mixed Methods Analysis. Journal of surgical education Lee, M. C., Melcer, E. F., Merrell, S. B., Wong, L. Y., Shields, S., Eddington, H., Trickey, A. W., Tsai, J., Korndorffer, J. R., Lin, D. T., Liebert, C. A. 2023

    Abstract

    As the American Board of Surgery transitions to a competency-based model of surgical education centered upon entrustable professional activities (EPAs), there is a growing need for objective tools to determine readiness for entrustment. This study evaluates the usability of ENTRUST, an innovative virtual patient simulation platform to assess surgical trainees' decision-making skills in preoperative, intra-operative, and post-operative settings.This is a mixed-methods analysis of the usability of the ENTRUST platform. Quantitative data was collected using the system usability scale (SUS) and Likert responses. Analysis was performed with descriptive statistics, bivariate analysis, and multivariable linear regression. Qualitative analysis of open-ended responses was performed using the Nielsen-Shneiderman Heuristics framework.This study was conducted at an academic institution in a proctored exam setting.The analysis includes n = 47 (PGY 1-5) surgical residents who completed an online usability survey following the ENTRUST Inguinal Hernia EPA Assessment.The ENTRUST platform had a median SUS score of 82.5. On bivariate and multivariate analyses, there were no significant differences between usability based on demographic characteristics (all p > 0.05), and SUS score was independent of ENTRUST performance (r = 0.198, p = 0.18). Most participants agreed that the clinical workup of the patient was engaging (91.5%) and felt realistic (85.1%). The most frequent heuristics represented in the qualitative analysis included feedback, visibility, match, and control. Additional themes of educational value, enjoyment, and ease-of-use highlighted participants' perspectives on the usability of ENTRUST.ENTRUST demonstrates high usability in this population. Usability was independent of ENTRUST score performance and there were no differences in usability identified in this analysis based on demographic subgroups. Qualitative analysis highlighted the acceptability of ENTRUST and will inform ongoing development of the platform. The ENTRUST platform holds potential as a tool for the assessment of EPAs in surgical residency programs.

    View details for DOI 10.1016/j.jsurg.2023.09.001

    View details for PubMedID 37821350

  • Does tranexamic acid increase venous thromboembolism risk among trauma patients? A prospective multicenter analysis across 17 level I trauma centers. Injury Knowlton, L. M., Arnow, K., Trickey, A. W., Sauaia, A., Knudson, M. M. 2023: 111008

    Abstract

    IMPORTANCE: The early use of tranexamic acid (TXA) has demonstrated benefit among some trauma patients in hemorrhagic shock. The association between TXA administration and thromboembolic events (including deep vein thrombosis (DVT), pulmonary embolism (PE) and pulmonary thrombosis (PT)) remains unclear. We aimed to characterize the risk of venous thromboembolism (VTE) subtypes among trauma patients receiving TXA and to determine whether TXA is associated with VTE risk and mortality.METHODS: We analyzed a prospective, observational, multicenter cohort data from the Consortium of Leaders in the Study of Traumatic Thromboembolism (CLOTT) study group. The study was conducted across 17 US level I trauma centers between January 1, 2018, and December 31,2020. We studied trauma patients ages 18-40 years, admitted for at least 48h with a minimum of 1 VTE risk factor and followed until hospital discharge or 30 days. We compared TXA recipients to non-recipients for VTE and mortality using inverse probability weighted Cox models. The primary outcome was the presence of documented venous thromboembolism (VTE). The secondary outcome was mortality. VTE was defined as DVT, PE, or PT.RESULTS: Among the 7,331 trauma patients analyzed, 466 (6.4%) received TXA. Patients in the TXA group were more severely injured than patients in the non-TXA group (ISS 16+: 69.1%vs. 48.5%, p<0.001) and a higher percentage underwent a major surgical procedure (85.8%vs. 73.6%, p<0.001). Among TXA recipients, 12.5% developed VTE(1.3% PT, 2.4% PE, 8.8% DVT) with 5.6% mortality. In the non-TXA group, 4.6% developed VTE (1.1% PT, 0.5% PE, 3.0% DVT) with 1.7% mortality. In analyses adjusting for patient demographic and clinical characteristics, TXA administration was not significantly associated with VTE (aHR 1.00, 95%CI: 0.69-1.46, p=0.99) but was significantly associated with increased mortality (aHR 2.01, 95%CI: 1.46-2.77, p<0.001).CONCLUSION: TXA was not clearly identified as an independent risk factor for VTE in adjusted analyses, but the risk of VTE among trauma patients receiving TXA remains high (12.5%). This supports the judicious use of TXA in resuscitation, with consideration of early initiation of DVT prophylaxis in this high-risk group.

    View details for DOI 10.1016/j.injury.2023.111008

    View details for PubMedID 37669883

  • Addressing knowledge gaps in Surgical Safety Checklist use: statistical process control analysis of a surgical quality improvement programme in Ethiopia. The British journal of surgery Nofal, M. R., Starr, N., Negussie Mammo, T., Trickey, A. W., Gebeyehu, N., Koritsanszky, L., Alemu, M., Tara, M., Alemu, S. B., Evans, F., Kahsay, S., Weiser, T. G. 2023

    Abstract

    BACKGROUND: The WHO Surgical Safety Checklist reduces morbidity and mortality after surgery, but uptake remains challenging. In particular, low-income countries have been found to have lower rates of checklist use compared with high-income countries. The aim of this study was to determine the impact of educational workshops on Surgical Safety Checklist use implemented as part of a quality improvement initiative in five hospitals in Ethiopia that had variable experience with the Surgical Safety Checklist.METHODS: From April 2019 to September 2020, each hospital implemented a 6-month surgical quality improvement programme, which included a Surgical Safety Checklist workshop. Statistical process control methodology was used to understand the variation in Surgical Safety Checklist compliance before and after workshops and a time-series analysis was performed using population-averaged generalized estimating equation Poisson regression. Checklist compliance was defined as correctly completing a sign in, timeout, and sign out. Incidence rate ratios of correct checklist use pre- and post-intervention were calculated and the change in mean weekly compliance was predicted.RESULTS: Checklist compliance data were obtained from 2767 operations (1940 (70 per cent) pre-intervention and 827 (30 per cent) post-intervention). Mean weekly checklist compliance improved from 27.3 to 41.2 per cent (mean difference 13.9 per cent, P = 0.001; incidence rate ratio 1.51, P = 0.001). Hospitals with higher checklist compliance at baseline had the greatest overall improvements in compliance, more than 50 per cent over pre-intervention, while low-performing hospitals showed no improvement.CONCLUSION: Surgical Safety Checklist workshops improved checklist compliance in hospitals with some experience with its use. Workshops had little effect in hospitals unfamiliar with the Surgical Safety Checklist, emphasizing the importance of multifactorial interventions and culture-change approaches. In receptive facilities, short workshops can accelerate behaviour change.

    View details for DOI 10.1093/bjs/znad234

    View details for PubMedID 37551706

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Li Ka Shing Learning and Knowledge Center
291 Campus Drive, Room LK120
Stanford, CA 94305
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