MedicalResearch.com Interview with: Dr Christopher Michael Cook MBBS Bsc(Hons) MRCP MRC Clinical Research Fellow NHLI, Cardiovascular Medicine, Imperial College London MedicalResearch.com: What is the background for this study? Response: FFR-CT is a novel non-invasive technique for estimating the functional significance of a coronary stenosis from CT coronary angiography images. A number of meta-analyses already exist for determining the...
Dr. Jinhui Zhao[/caption]
Dr. Jinhui Zhao PhD
Scientist, Centre for Addictions Research of BC
University of Victoria
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: There are now many studies questioning the validity of the theory that moderate alcohol consumption protects against heart disease. We provided an up to date and comprehensive review of the evidence from ‘cohort’ studies i.e. those that assess health risk behaviours of people then follow them up for a number of years to see what characteristics predict death from a particular condition. We wished to test the theory that the appearance of health benefits in relation to heart disease is due to biases that accumulate and become more severe when cohorts are recruited at older ages (e.g. over 55 years). We found evidence to support this hypothesis. Moderate drinkers recruited before 55 years of age did not show any evidence of reduced risk of heart disease even when followed up into old age. Moderate drinkers from the older cohorts, however, did appear to have significant benefits – a finding we attribute to selection biases that accumulate across the life-course.
Several published meta-analyses showed inconsistent findings about how alcohol consumption affects the risk of coronary heart disease (CHD). Most systematic reviews find associations between low-volume alcohol consumption and reduced CHD risk, while some also find increased CHD risk for higher levels of consumption (Maclure 1993, Corrao, Rubbiati et al. 2000, Corrao, Bagnardi et al. 2004, Ronksley, Brien et al. 2011, Roerecke and Rehm 2012). More recent evidence has accumulated to suggest that the case for cardio-protection may be less straightforward. The association of alcohol consumption with CHD may be confounded or modified by other factors such as age and sex and / or biased by those factors which have not been investigated or controlled for in these previously published studies.
Dr. Peter Ganz[/caption]
Peter Ganz, MD
Chief, Division of Cardiology
Director, Center of Excellence in Vascular Research
Zuckerberg San Francisco General Hospital
Maurice Eliaser Distinguished Professor of Medicine
University of California, San Francisco
MedicalResearch.com: What is the background for this study? What are the main findings?
Dr. Ganz: The research described in the JAMA paper involved measuring 1,130 different proteins in nearly 2000 individuals with apparently stable coronary heart disease, who were followed up to 11 years. Initially, two hundred different proteins were identified whose blood levels could be related to the risk of heart attacks, strokes, heart failure and death, and ultimately a combination of nine proteins was selected for a risk prediction model, based on their combined accuracy and sensitivity.
Application of these findings to samples of patients with stable coronary heart disease demonstrated that some of those who were deemed clinically stable instead had a high risk of adverse cardiovascular outcomes, while other patients with the same clinical diagnosis had a very low risk. Thus, individuals who all carried the same clinical diagnosis of stable coronary heart disease had a risk of an adverse cardiovascular event that varied by as much as 10-fold, as revealed by analysis of the levels of the nine proteins in their blood. Given such large differences in risk and outcomes, patients could reasonably opt to be treated differently, depending on their level of risk. We hope that in the future, management of patients with stable angina will at least in part rely on risk assessment based on levels of blood proteins.