Absolute risk assessment for guiding cardiovascular risk management in a chest pain clinic (Letter)

Abstract

To the Editor: We read with interest the study by Black and colleagues1 on the effectiveness of a pro-active risk factor management strategy based on absolute cardiovascular disease risk score compared with usual care, in a rapid access chest pain clinic setting. The study suggested that such a strategy significantly improved 5-year cardiovascular risk scores; however, we would consider some caution before reaching such a conclusion. Although the authors point out several potential sources for bias in their study, there is an additional one that has not been highlighted. In the results, the authors state that “the increase in use of guideline-based therapies was similar in the two groups,” yet do not go on to explain the differential effect as to why the blood pressure and lipid profiles decreased in the interventional group only. We suggest that the reason for this lies in a fundamental difference between the groups selected. The interventional group at baseline was receiving proportionately greater amounts of lipid-lowering and anti-hypertensive therapy: 56% and 30% higher, respectively, than in the control arm. These higher treatment rates may explain the lower blood pressure, the lipid profiles observed and, consequently, the improved final risk scores in the interventional arm. Also, as the authors pointed out, almost a third of eligible patients approached declined to participate and is therefore an important source of potential selection bias. We also note that the offer of referral to a public smoking cessation service was limited to those in the intervention group. National guidelines recommend this strategy as part of standard care,2 and hence we question whether this intervention should truly be considered to deviate from best practice or usual care.