Several studies have clearly demonstrated the increased risk for CVD in women with a history of preeclampsia [
1,
3]. Especially women after early and severe preeclampsia are at higher risk for future CVD [
1,
10]. The 2011 American Heart Association guidelines on cardiovascular disease prevention in women recognise pregnancy as a unique chance to predict women’s lifetime cardiovascular risk, as pregnancy-related complications may unmask premature vascular or metabolic diseases. Therefore, appropriate monitoring of CVD risk factors in these high-risk women is recommended [
5]. The 2012 European Society of Cardiology guideline on CVD prevention also indicates that prevention of CVD in women ideally starts during pregnancy and lasts until end of life [
7]. However, in standard primary care obstetric history is not yet routinely incorporated in risk assessment [
27].
In this model-based analysis we assess the expected cost-effectiveness of a hypertension screening strategy in women after preeclampsia. We found that a relatively simple preventive strategy, consisting of a yearly blood pressure measurement at the GP’s surgery after index pregnancy, gives an expected saving of € 1071 per person and a slight increment of 0.03 QALY (12 days living in perfect health) per screened person.
Strengths and limitations
The power of this Markov model is founded in the combination of the available evidence on CVD post preeclampsia. Our model could be of help in making evidence-based decisions on prevention post preeclampsia, without performing costly long-term follow-up studies.
However, our model has some limitations. To estimate risk of hypertension in women after preeclampsia, we used a cohort of women post early preeclampsia. As early preeclampsia confers the highest future CVD risk of all hypertensive pregnancy disorders [
1,
10], the results of our Markov model should not be extrapolated to all women post hypertensive pregnancy disorders. As future risk for hypertension and CVD are lower in women with late compared with early preeclampsia, the magnitude of screening effects will be smaller.
Secondly, as prospective data in women after early preeclampsia are relatively scarce, we also used CVD risk data of patients with less severe preeclampsia to estimate risk of future CVD after preeclampsia. This may have underestimated the net effect of hypertension screening on CVD risk in women post early preeclampsia in our model. Nonetheless, the presented data are convincing and underline the need for preventive measures in women post early preeclampsia.
In our model we used mainly Dutch costs. As costs in other jurisdictions will be different from the Dutch situation, our results could be less generalisable to other health systems. However, in general costs in the US tend to be higher than in the Dutch healthcare system, so savings in the US will probably be larger. On the other hand, the Dutch well-structured GP system can adopt our intervention strategy easily, whereas this might be more difficult in other countries.
To perform our model we made some assumptions. First, we assumed that women with non-treated hypertension in the non-intervention strategy had a 20 mmHg higher SBP than women with adequately treated hypertension in the intervention strategy, based on our PREVFEM data. This seems reliable if women in the intervention strategy are directly well controlled and treated, but in current daily practice this is disappointing 28 s, in our model participants were all compliant in taking their antihypertensive medication, in real practice a quarter of women on blood pressure medication do not take their medication regularly, which will reduce the calculated preventive effects [
29]. However, sensitivity analysis shows that screening remains cost-effective with an adherence rate of 75 %.
To estimate the increase in CVD risk in the presence of increased blood pressure we used a meta-analysis and two cohort studies; these studies consisted of men and women with an age distribution between 35 and 65 years. Use of data based on both men and women might have overrated over effects as men have higher CVD rates at younger ages [
30].
Clinical implications and future perspective
In our model we demonstrated that a yearly blood pressure measurement at the GP’s office in women after early preeclampsia is cost-effective in preventing CVD. However, in a time horizon of 20 years we found only a slight gain in QALYs (12 days living in perfect health). Although this gain is associated with cost savings, the clinical relevance of this small gain in QALYs can be debated. Besides this, we also need to consider the willingness of young, healthy women to use blood pressure medication, with potential side effects, for a 12-day longer life in perfect health. Also, it is unclear what the effects of routine screening are on quality of life in healthy young women. We expect a small negative effect on quality of life; however, because of a lack of data on the magnitude of these effects this was not incorporated in our model. A pilot study on screening might give more insight into these effects.
Further, before considering incorporation of a screening strategy into new primary care guidelines, it should be investigated if the strategy used is attainable for GPs. The potential burden for GPs may be decreased by starting screening at 10-year postpartum or by reducing the frequency of the screening. More research is needed to establish the best time schedule for hypertension screening. For the future, there might be an interesting role for e-health medicine in prevention of CVD in young high-risk women after preeclampsia.