Risk for cardiovascular (CV) events is higher for patients treated with immune checkpoint inhibitors (ICIs), but International Classification of Diseases (ICD) codes do not always capture all the information necessary to create a complete picture of the incidence of cardiovascular events related to ICI therapy.
Researchers in Colorado collaborated to learn more about CV event occurrence in these patients and assess the accuracy of diagnosis. Their findings were published in JACC: CardioOncology.
The researchers used data from a cohort of 1813 ICI-treated patients in the University of Colorado health system between January 2011 and April 2019. The data identifying potential CV events based on ICD codes were pulled from the electronic medical record system; 2 cardiologists reviewed the records and adjudicated the diagnoses using established definitions. Results of the 2 methods were compared.
Among a real-world data set of patients, venous thromboembolic events (VTEs), myocardial infarction (MI), heart failure, and stroke occurred much more frequently among ICI-treated patients than myocarditis. However, VTEs, MI, heart failure, and stroke occurred both before and after ICI treatment, whereas myocarditis was primarily detected posttreatment.
“Our observation that myocarditis was observed in 1 patient before ICI and 6 patients after ICI is consistent with reports of ICI-associated inflammation,” the researchers noted.
“The relative rarity of myocarditis relative to other CV events underscores the importance of appropriate evaluation and management of patients presenting with cardiac symptoms, particularly as ICI therapy evolves to earlier and broader use,” they added.
VTEs were the most common CV event in this patient population, occurring in 11.4% of the patients before ICI therapy and 11.3% after ICI therapy. In addition, coding and adjudication correlated well for VTE and MI, but not as well for myocarditis and heart failure.
“This work shows that ICD codes can be used to determine the incidence of MI and VTE; however, this method lacks the fidelity needed to accurately identify other CV events,” the researchers wrote, adding that adjudication with standardized definitions was helpful to better understand the incidence of CV events in these patients.
Future studies need to look at identifying predictors of CV events in patients undergoing ICI therapy so effective strategies could be developed to reduce their risk, suggested the researchers.
With regard to limitations, the institution attracts patients who may only interact with the health system during cancer treatment so it wasn’t feasible in the data set to determine if patients were responding to ICI therapy and correlate that to CV events. “Because the EMR reflects an incomplete health record, we are cautious about inferring CV rates within our cohort,” the researchers wrote.
Additionally, the study did not include time-to-event analysis, and the data set did not include cardiac biomarker data. ICD data also were dependent on the entry of billing codes.
Disclosures: Some authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.
Kondapalli L, Hsia J, Miller R, Flaig TW, Bonaca MP. Burden of cardiovascular disease in immune checkpoint inhibitor–treated patients: reconciling adjudicated and coded outcomes. JACC CardioOncol. 2022;4(5):649-656. doi:10.1016/j.jaccao.2022.09.003