Anna Siefkas

Ms. Anna Siefkas

orcid

Research Focus & Metrics

Academic Career Length

10Years (2017-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 September 2020 in Computers in Biology and Medicine
Verified
Journal Article
Open access
HBHoyt Burdick
Hoyt Burdick
CLCarson Lam
Carson Lam
SMSamson Mataraso
Samson Mataraso
ASAnna Siefkas
Anna Siefkas
GBGregory Braden
Gregory Braden
RDRitankar Das
Ritankar Das
Currently, physicians are limited in their ability to provide an accurate prognosis for COVID-19 positive patients. Existing scoring systems have been ineffective for identifying patient decompensation. Machine learning (ML) may offer an alternative strategy. A prospectively validated method to predict the need for ventilation in COVID-19 patients is essential to help triage patients, allocate resources, and prevent emergency intubations and their associated risks. In a multicenter clinical trial, we evaluated the performance of a machine learning algorithm for prediction of invasive mechanical ventilation of COVID-19 patients within 24 h of an initial encounter. We enrolled patients with a COVID-19 diagnosis who were admitted to five United States health systems between March 24 and May 4, 2020. 197 patients were enrolled in the REspirAtory Decompensation and model for the triage of covid-19 patients: a prospective studY (READY) clinical trial. The algorithm had a higher diagnostic odds ratio (DOR, 12.58) for predicting ventilation than a comparator early warning system, the Modified Early Warning Score (MEWS). The algorithm also achieved significantly higher sensitivity (0.90) than MEWS, which achieved a sensitivity of 0.78, while maintaining a higher specificity (p < 0.05). In the first clinical trial of a machine learning algorithm for ventilation needs among COVID-19 patients, the algorithm demonstrated accurate prediction of the need for mechanical ventilation within 24 h. This algorithm may help care teams effectively triage patients and allocate resources. Further, the algorithm is capable of accurately identifying 16% more patients than a widely used scoring system while minimizing false positive results.

1 January 2021 in Clinical and Applied Thrombosis/Hemostasis
Verified
Journal Article
Open access
PDF file
LRLogan Ryan
Logan Ryan
SMSamson Mataraso
Samson Mataraso
ASAnna Siefkas
Anna Siefkas
EPEmily Pellegrini
Emily Pellegrini
GBGina Barnes
Gina Barnes
RDRitankar Das
Ritankar Das
Deep venous thrombosis (DVT) is associated with significant morbidity, mortality, and increased healthcare costs. Standard scoring systems for DVT risk stratification often provide insufficient stratification of hospitalized patients and are unable to accurately predict which inpatients are most likely to present with DVT. There is a continued need for tools which can predict DVT in hospitalized patients. We performed a retrospective study on a database collected from a large academic hospital, comprised of 99,237 total general ward or ICU patients, 2,378 of whom experienced a DVT during their hospital stay. Gradient boosted machine learning algorithms were developed to predict a patient’s risk of developing DVT at 12- and 24-hour windows prior to onset. The primary outcome of interest was diagnosis of in-hospital DVT. The machine learning predictors obtained AUROCs of 0.83 and 0.85 for DVT risk prediction on hospitalized patients at 12- and 24-hour windows, respectively. At both 12 and 24 hours before DVT onset, the most important features for prediction of DVT were cancer history, VTE history, and internal normalized ratio (INR). Improved risk stratification may prevent unnecessary invasive testing in patients for whom DVT cannot be ruled out using existing methods. Improved risk stratification may also allow for more targeted use of prophylactic anticoagulants, as well as earlier diagnosis and treatment, preventing the development of pulmonary emboli and other sequelae of DVT.

11 June 2021 in Medicine
Verified
Journal Article
Open access
CGChristine Giang
Christine Giang
JCJacob Calvert
Jacob Calvert
KRKeyvan Rahmani
Keyvan Rahmani
GBGina Barnes
Gina Barnes
ASAnna Siefkas
Anna Siefkas
RDRitankar Das
Ritankar Das
Ventilator-associated pneumonia (VAP) is the most common and fatal nosocomial infection in intensive care units (ICUs). Existing methods for identifying VAP display low accuracy, and their use may delay antimicrobial therapy. VAP diagnostics derived from machine learning (ML) methods that utilize electronic health record (EHR) data have not yet been explored. The objective of this study is to compare the performance of a variety of ML models trained to predict whether VAP will be diagnosed during the patient stay. A retrospective study examined data from 6126 adult ICU encounters lasting at least 48 hours following the initiation of mechanical ventilation. The gold standard was the presence of a diagnostic code for VAP. Five different ML models were trained to predict VAP 48 hours after initiation of mechanical ventilation. Model performance was evaluated with regard to the area under the receiver operating characteristic (AUROC) curve on a 20% hold-out test set. Feature importance was measured in terms of Shapley values. The highest performing model achieved an AUROC value of 0.854. The most important features for the best-performing model were the length of time on mechanical ventilation, the presence of antibiotics, sputum test frequency, and the most recent Glasgow Coma Scale assessment. Supervised ML using patient EHR data is promising for VAP diagnosis and warrants further validation. This tool has the potential to aid the timely diagnosis of VAP.

22 October 2020 in JMIR Public Health and Surveillance
Verified
Journal Article
Open access
AAAngier Allen
Angier Allen
SMSamson Mataraso
Samson Mataraso
ASAnna Siefkas
Anna Siefkas
HBHoyt Burdick
Hoyt Burdick
GBGregory Braden
Gregory Braden
RDRitankar Das
Ritankar Das
Background: Racial disparities in health care are well documented in the United States. As machine learning methods become more common in health care settings, it is important to ensure that these methods do not contribute to racial disparities through biased predictions or differential accuracy across racial groups. Objective: The goal of the research was to assess a machine learning algorithm intentionally developed to minimize bias in in-hospital mortality predictions between white and nonwhite patient groups. Methods: Bias was minimized through preprocessing of algorithm training data. We performed a retrospective analysis of electronic health record data from patients admitted to the intensive care unit (ICU) at a large academic health center between 2001 and 2012, drawing data from the Medical Information Mart for Intensive Care–III database. Patients were included if they had at least 10 hours of available measurements after ICU admission, had at least one of every measurement used for model prediction, and had recorded race/ethnicity data. Bias was assessed through the equal opportunity difference. Model performance in terms of bias and accuracy was compared with the Modified Early Warning Score (MEWS), the Simplified Acute Physiology Score II (SAPS II), and the Acute Physiologic Assessment and Chronic Health Evaluation (APACHE). Results: The machine learning algorithm was found to be more accurate than all comparators, with a higher sensitivity, specificity, and area under the receiver operating characteristic. The machine learning algorithm was found to be unbiased (equal opportunity difference 0.016, P=.20). APACHE was also found to be unbiased (equal opportunity difference 0.019, P=.11), while SAPS II and MEWS were found to have significant bias (equal opportunity difference 0.038, P=.006 and equal opportunity difference 0.074, P<.001, respectively). Conclusions: This study indicates there may be significant racial bias in commonly used severity scoring systems and that machine learning algorithms may reduce bias while improving on the accuracy of these methods.

1 September 2021 in Health Policy and Technology
Verified
Journal Article
Open access
CLCarson Lam
Carson Lam
JCJacob Calvert
Jacob Calvert
ASAnna Siefkas
Anna Siefkas
GBGina Barnes
Gina Barnes
EPEmily Pellegrini
Emily Pellegrini
RDRitankar Das
Ritankar Das
Objective: In the wake of COVID-19, the United States (U.S.) developed a three stage plan to outline the parameters to determine when states may reopen businesses and ease travel restrictions. The guidelines also identify subpopulations of Americans deemed to be at high risk for severe disease should they contract COVID-19. These guidelines were based on population level demographics, rather than individual-level risk factors. As such, they may misidentify individuals at high risk for severe illness, and may therefore be of limited use in decisions surrounding resource allocation to vulnerable populations. The objective of this study was to evaluate a machine learning algorithm for prediction of serious illness due to COVID-19 using inpatient data collected from electronic health records.

29 December 2021 in Journal of Applied Gerontology
Verified
Journal Article
Open access
PDF file
ASAnna Siefkas
Anna Siefkas
EMEllen P. McCarthy
Ellen P. McCarthy
BLBruce Leff
Bruce Leff
ADAlyssa B. Dufour
Alyssa B. Dufour
MHMarian T. Hannan
Marian T. Hannan
Fall prevention strategies exist, but little is known about factors that influence whether they are used. We assessed whether social isolation modifies the association between fear of falling (FOF) and bathroom environmental modification. Data were included from 2858 Medicare beneficiaries in the National Health and Aging Trends Study. FOF and social isolation were assessed at baseline (2011); new bathroom modifications were assessed 1-year post-baseline. Social network size was dichotomized as any versus no social contacts. Logistic regression assessed associations between FOF and bathroom modification. Effect modification between FOF and social isolation was assessed with multiplicative interaction terms. FOF was associated with increased odds of bathroom modification. We observed a statistically significant interaction between FOF and social isolation (p = 0.03). Among those with no social contacts, FOF was associated with reduced odds bathroom modification that did not reach statistical significance (OR 0.5, 95% CI 0.2–1.3).