Date of Award
Summer 8-25-2023
Document Type
Open Access Thesis
Degree Name
Master of Medical Science (MMSc)
First Advisor
Brita Roy MD, MPH, MHS
Second Advisor
Lou Hart, MD
Abstract
Abstract/Summary:
Background: “The Society of Thoracic Surgeons mortality risk calculator”, which includes a race variable, is recommended for estimating Short- term (30 day) predicted risk of mortality after isolated coronary artery bypass graft, with a risk estimate of 3-4% stratifying patients into intermediate risk, a risk estimate above 5% stratifying patients into high risk for surgery and a risk estimate above 8% stratifying patients into the very high-risk category. We compared differences between Black and White individuals in Society of Thoracic Surgeons-predicted risk of mortality across various plausible risk factor combinations with the aim of evaluating if using the predictive calculator might result in different surgical decisions in Black versus White individuals with identical risk profiles.
Methods: We generated in silico patient risk profiles by combining numerical risk factors (age {10 year intervals 60-70}, ejection fraction {5% intervals 30-40}, weight {50 kg, 80kg 130kg, hematocrit {25%,40%}, creatinine {0.8, 1, 1.3, 1.7, 2}) and binary risk factors (gender, insurance status, peripheral arterial disease, diabetes on insulin, lung disease, and number of diseased vessels). We compared Society of Thoracic Surgeons predicted risk of mortality in Black and White individuals with identical risk profiles. Secondary outcomes measured included total morbidity/mortality, risk of stroke, risk of renal failure, risk of prolonged ventilation, and risk of long stay >14days.
Findings: For our in-silico analysis, we evaluated 5,041 risk profiles for men and 4,768 risk profiles for women after excluding risk profiles that generated risk of mortality below 2% or above 10%. There were 703 risk profiles associated with Society of Thoracic Surgeon Predicted risk of mortality (PROM) above 5% for Black men but not for White men (median risk difference [RD] .827%, range 0.32-2.83; median relative risk [RR] 1.18, range 1.06-1.89). There were 189 risk profiles associated with a predicted risk of mortality (PROM) above 8% for Black men but not for White men (median risk difference [RD] .81% , range 0.77-3.24; median relative risk [RR] 1.11, range 1.10-1.54). There were 616 risk profiles associated with a predicted risk of mortality (PROM) above 5% for Black women but not for White women (median risk difference [RD] 0.80%, range 0.49%-0.91%; median relative risk [RR] 1.18, range 1.11-1.18). Lastly, there were 347 risk profiles associated with a predicted risk of mortality (PROM) above 8% for Black women but not for White women (median risk difference [RD] 0.81% , range 0.77%-2.81%; median relative risk [RR] 1.11, range 1.10-1.50). There were no risk profiles using the Society of Thoracic Surgeons short term calculator in which predicted risk of mortality for White individuals was above 5% risk and PROM for Black individuals was below 5%, nor any risk profiles which PROM for White individuals was above 8% risk and PROM for Black individuals was below 8%.
Interpretation: The STS calculator might produce divergent risk of mortality estimates for Black and White individuals with identical risk profiles, leading to a difference in treatment plans, timing of surgery, or long-term outcomes.
Recommended Citation
Marmolejos, Kiara, "Differences in Predicted Risk of Mortality after Coronary Artery Bypass Graft Between Black and White Patients with Identical Clinical Profiles Using the Society of Thoracic Surgeons Calculator: an in-silico Cohort Study" (2023). Yale School of Medicine Physician Associate Program Theses. 195.
https://elischolar.library.yale.edu/ysmpa_theses/195
