Discordances between predicted and actual risk in obese patients with suspected cardiac ischaemia

Abstract

ObjectivesTo test the relationship between increasing severity of obesity, calculated risk and observed outcomes.MethodsPatients with symptoms suggestive of coronary artery disease (CAD) (n=10 003) were stratified according to body mass index (BMI). We compared risk factors, pooled risk scores and physicians’ perception of risk. Cox regression tested the association between BMI and (1) presence of obstructive CAD and (2) composite clinical endpoints (death, cardiovascular death, unstable angina hospitalisation and myocardial infarction).ResultsBMI was ≥30 kg/m2 in 48% of patients and ≥35 in 20%. Increasingly obese patients were younger, female and non-smoking but with higher prevalence of hypertension, diabetes, black race and sedentary lifestyle. Pooled risk estimates of CAD were highest in those with mid-range BMI. In contrast, physicians’ estimation of the likelihood of significant CAD based on clinical impression increased progressively with BMI. For a 10% increase in the Diamond-Forrester probability of CAD, the adjusted OR for obstructive CAD was 1.5 (95% CI 1.4 to 1.5) in patients with BMI <35, but only 1.2 (95% CI 1.1 to 1.3) in those with BMI ≥35 (interaction p<0.001). Framingham Risk Score increased across increasing BMI categories. However, there was a strong and consistent inverse relationship between degree of obesity and all three composite clinical endpoints over a median 25 months of follow-up.ConclusionsDespite perceptions of higher risk and higher risk scores, increasingly obese patients had obstructive CAD less frequently than predicted and had fewer adverse clinical outcomes. There is a need for risk assessment tools and guidelines that account for obesity.Trial registration numberNCT01174550.

The aging human body shape

“…"Paradoxically," previous studies reported differences in short-, medium-, and long-term mortality showing partly better survival for overweight compared with normal and underweight individuals 29 . Moreover, despite perceptions of higher risk, increasingly obese patients can have fewer adverse clinical outcomes than expected 30 . Hence, there is a need for better risk assessment for obesity.…”

Relationship of Body Fat and Left ventricular hypertrophy with the Risk of All-cause Death in Patients with Coronary Artery Disease

“…For patients whose left ventricular is hypertrophic due to diverse causes, it seemed that higher body fat was correlated with lower risk of mortality. Intuitively, physicians would expect the likelihood of CAD to increase with BMI, but in fact is not the case, and the severity of obesity may be inversely correlated with poor outcomes in patients with suspected myocardial ischemia [10]. In an observational study of median follow-up duration of 68 months, obesity was associated with a decreased risk of mortality in patients with dipyridamole induced ischemic regional wall motion abnormalities or abnormal coronary ow velocity reserve (HR 0.58, 95% CI 0.40-0.84; p = 0.003) [11].…”

Association of Metabolic Phenotypes With Coronary Artery Disease and Cardiovascular Events in Patients With Stable Chest Pain

“…We previously reported in the PROM-ISE cohort that the level of obesity had an impact on the physicians' preferred functional test and that the diagnostic yield of CTA was less adversely affected by obesity compared with nuclear myocardial perfusion imaging (24). Also, increasingly obese patients had obstructive CAD less frequently than predicted by their health care providers and a better clinical outcome (25). Among patients with diabetes, a CTA strategy resulted in fewer MACE compared with those without diabetes (26).…”