Clarification on blood pressure study
Following the publication of your article, ARBs are the 'best BP drug' in the real world1 we would like to clarify a few points regarding this study.
This study explored the BP lowering effect by different drug classes in UK primary care using the THIN database. The THIN dataset consists of anonymised patients' records from over 300 practices and 5 million patients in UK primary care. The analysis was performed by Cardiff Research Consortium (CRC) in collaboration with members of the medical team at sanofi-aventis and Bristol-Myers Squibb
The study demonstrated that in a real world setting patients receiving ARBs are observed to achieve greater blood pressure lowering effects compared to patients on other antihypertensive classes, whether as a single agent (monotherapy) or when considered in the context of ARB against non ARB-containing treatment pathways.
The validity of observational studies has been gaining recognition and it has previously been shown by Concato et al2 that well conducted observational studies do not systematically overestimate the magnitude of the effects of treatment as compared with those in randomised, controlled trials on the same topic.
Dr. McCormack's comment that 'more patients may get to target BP because of other reasons, such as compliance and tolerability' is a topical one. Our study was not designed to explore reasons such as these behind the differences in BP seen. We believe the pharmaceutical effectiveness of any agent is balanced by its safety and tolerability profile, and agree that the greatest benefit to the patient is the combination of maximum efficacy and tolerability.
It is important to note that this study did not intend to challenge any current guidelines (NICE-BHS3) and had the objective of exploring the BP lowering effect, in a real world setting, of commonly used antihypertensive drugs.
Epidemiological studies have previously demonstrated that even a small reduction in blood pressure can reduce the risk of stroke and deaths from ischaemic heart disease. According to Lewington et al4 a 2mmHg SBP reduction reduces fatal stroke by 10% and ischaemic heart disease mortality by seven per cent. However, our study did not aim to explore the association between BP reduction and clinical outcomes but merely focused on observing the BP lowering effect of different antihypertensive therapies alone or in combination in UK primary care.
Peter Sharplin, Cardiff Research Consortium
Dr Nicolas Wisniacki, sanofi-aventis