Comparison of self-perceived cardiovascular disease risk among smokers with Framingham and PROCAM scores: a cross-sectional analysis of baseline data from a randomised controlled trial

Abstract

Objectives: Previous studies suggest that smokers have a misperception of their 10-year cardiovascular risk. We aimed to compare 10-year cardiovascular risk self-perception and calculated risk among smokers willing to quit and assess the determinants of a possible misperception.

Design: Cross-sectional secondary analysis of baseline data from a randomised controlled trial of smoking cessation.

Participants: 514 participants, mean age 51.1 years, 46% women, 98% Caucasian. Eligible participants were regular smokers, aged between 40 and 70 years, with a consumption of at least 10 cigarettes per day for at least a year. None of them had experienced cardiovascular disease before. Exclusion criteria comprised a history of myocardial infarction, coronary heart disease, stroke, heart failure, peripheral vascular disease, carotid atherosclerosis or cardiac arrhythmia. Participants with renal or liver failure, psychiatric disorders, substance and alcohol abuse and with smoking cessation therapies were excluded.

Interventions: Participants were asked to estimate their 10-year cardiovascular risk using a 3-item scale corresponding to high-risk, moderate-risk and low-risk categories. We compared their risk perception with Framingham and Prospective Cardiovascular Munster Study (PROCAM) scores. We used multivariable-adjusted logistic regression models to determine characteristics of participants who underestimate their risk versus those who correctly estimate or overestimate it.

Results: Between 38% and 42% of smokers correctly perceived their 10-year cardiovascular risk, and 39-50% overestimated their 10-year cardiovascular risk while 12-19% underestimated it compared with their calculated 10-year cardiovascular risk depending on the score used. Underestimation of 10-year cardiovascular risk was associated with male gender (OR 8.16; CI 3.83 to 17.36), older age (OR 1.06; CI 1.02 to 1.09), and the presence of hyperlipidaemia (OR 2.71; CI 1.47 to 5.01) and diabetes mellitus (OR 13.93; CI 3.83 to 50.66).

Conclusions: Among smokers, misperception of their 10-year cardiovascular risk is common, with one-fifth underestimating it. These findings may help physicians target patients with such characteristics to help them change their health behaviour and adherence to risk-reduction therapy.

Trial registration number: NCT00548665; Post-results.

Keywords: EPIDEMIOLOGY; PREVENTIVE MEDICINE; PRIMARY CARE.

Conflict of interest statement

Conflicts of Interest: None declared.

Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Figures

Figure 1

Determinants of underestimation (Framingham). ‘The ORs and respective 95% CIs are presented on a log scale. Values above 1.0 (right of the dashed vertical line) present an increased risk of underestimating cardiovascular risk according to Framingham risk score, while values below 1.0 (left of the dashed line) present a decreased risk of underestimating cardiovascular risk. All characteristics were analysed as categorical variables, except for age in years as a continuous variable. The presence of hypertension was defined as a blood pressure ≥140/90 mm Hg in patients without diabetes and ≥130/80 mm Hg in patients with diabetes. The presence of hyperlipidaemia was defined according to the level of cardiovascular risk: the threshold for patients with high, intermediate and low cardiovascular risk was ≥2.6 mmol/L, ≥3.4 mmol/L and ≥4.1 mmol/L, respectively. The presence of diabetes was defined by levels of fasting glucose ≥7 mmol/L or glucose at any time ≥11.1 mmol/L. Obesity was defined as a body mass index ≥30 kg/m2 (weight in kilograms divided by height in meters squared)’.