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Principal Investigator
Martin Tammemagi
Brock University
Position Title
About this CDAS Project
NLST (Learn more about this study)
Project ID
Initial CDAS Request Approval
Sep 21, 2015
NLST screen detected cardiovascular disease - impact on mortality and lung cancer screening
This study plans to evaluate the number of incidental cardiac abnormalities identified on National Lung Screening Trial (NLST) low dose computed tomography (LDCT) screens and estimate the distributions of cardiovascular mortality risk factors present in these individuals, including body mass index (BMI), smoking status, and history of diabetes, hypertension, cardiovascular disease and stroke. These data will be obtained from baseline questionnaire and in addition smoking history data will be captured from annual summary updates. Overall and cardiovascular mortality will be compared between individuals with and without CT-identified cardiovascular disease and with and without elevated cardiovascular mortality risk factor scores. The potential impact of interventions to reduce the prevalence of cardiovascular mortality risk factors on cardiovascular mortality and on lung cancer screening program effectiveness will be evaluated. Sex differences in risk factor distributions, associations and impacts on screening effectiveness will be assessed. To the extent possible, subset analysis will be carried out on specific cardiovascular abnormality categories, which were entered in text format on the diagnosis form in the LSS part of the NLST.
The study design is prospective cohort and logistic and Cox proportional hazard regression will be used to carry out modeling. For external generalizability to lung cancer screening programs, the primary focus of the study is on findings in the NLST LDCT arm. However, data from the NLST CXR arm and from the PLCO will also be analyzed to obtain more valid and precise estimates of (1) frequencies of cardiac mortality risk factors in the general population and in high-risk individuals who would be eligible for lung cancer screening, and (2) effect estimates of the associations between risk factors and cardiac mortality.

The study aims/questions are:
1. What is the prevalence of cardiovascular abnormalities observed in the LDCT arm of the NLST?
2. What are the distributions of cardiovascular mortality risk factors in those with and without cardiovascular abnormalities observed on LDCT?
3. What is the incidence of cardiovascular-specific death in those with and without cardiovascular abnormalities observed on their LDCT screen?
4. If an association exists between LDCT-detected cardiovascular abnormalities and cardiovascular death, are they mediated by modifiable risk factors present at baseline, such as BMI, smoking, hypertension and diabetes? The latter two being controllable by medications and life-style modifications.
5. Evaluate the number of cardiovascular deaths that could be averted if effective interventions could be implemented following discovery of a cardiovascular abnormality on LDCT screening. A realistic range of effect for the interventions would be assessed.
6. Evaluate the impact on lung cancer screening effectiveness if the competing cause of death due to cardiovascular disease can be reduced, and evaluate such an impact separately for men and women.


To be determined. This will be completed at a later date.