Brett et al recently described a randomised trial of cardiovascular disease (CVD) risk reduction in three general practices.1 Suboptimal trial design may be a substantial contributor of concern about the efficacy and cost-effectiveness of such primary prevention interventions by health professionals.2 We are concerned that such shortcomings also feature in their study.
The study aimed to measure the effect on CVD risk of more frequent GP visits. The number of study visits actually received was not specified, and is crucially important. Based on a small sample, opportunistic group participants received clinically significantly more ‘non-study’ GP visits, ostensibly unrelated to the intervention but possibly not. Also, the study design did not allow an effect to occur between the final GP visit and data collection. Therefore, we estimate that they potentially compared a mean of 9.6 intervention group visits with a control group mean of 7.8 visits (and not 5 versus 2 visits, as claimed). Similar levels of care may explain a lack of between-group differences for the primary outcome.
Counselling provided was unclear. Apart from risk measurement and target specification, GP-counselling was simply deemed ‘individualised’ and ‘offered as appropriate’ — further details would be welcomed. No framework for behavioural change is specified, nor is any protocol for initiation or intensification of drug treatment, despite potential influence on outcomes.2 A substantial practice nurse role is hinted at in the discussion section but never described.
We are also concerned by the authors' conclusion that ‘the study demonstrates that absolute cardiovascular risk can be improved by primary prevention strategies’. This misinterprets minor (and occasionally significant) improvements to individual risk factors — there was no significant between-group reduction in overall CVD risk. The authors also conclude that a ‘targeted approach using absolute risk calculators can be used in primary care to modify global CVD risk assessment’ — given that risk calculators were employed for both study arms, it should not be implied that this was evaluated.
- © British Journal of General Practice 2012