Cardiovascular diseases

iMTA used observational data to assess the hospital costs for acute myocardial infarct, most notably the cost of the first myocardial infarct. Also the costs of stroke. For stroke, the inpatient days are the most important cost-driver, around two-thirds of total costs.

In addition, In an international study, iMTA has studied the burden of providing informal care for patients with atrial fibrillation. Caregiving for a patient with atrial fibrillation showed to be associated with a substantial objective and subjective burden for the caregiver. There were also considerable societal costs involved in providing informal care. The results of this study can be used in economic evaluations that comprehend the impact on caregivers.

iMTA used a bottom-up costing approach to compare the costs of two cardiac monitors for detecting atrial and ventricular arrythmias, in two different implantation settings. Data were collected in different hospitals in the Netherlands, France and the UK. Information was collected on various cost components in the study, including labour, materials, equipment and overhead costs.

iMTA has done CEAs of the real-world implementation of 9 integrated care programs for cardiovascular risk management.

iMTA performed early HTA studies into primary prevention in cardiovascular diseases, as well as biomarker tests. iMTA is also working on stroke, estimating the cost-effectiveness of non-invasive imaging technologies that are currently being developed to improve future stroke prediction to identify patients with a recent TIA or minor ischemic stroke for surgery. iMTA estimated the minimum performance (i.e., sensitivity and specificity) that a new test must have in order for it to be cost-effective versus currently available test strategies. Stroke, estimating cost-effectiveness of biomarkers which can predict the probability of a stroke event.

A good example of a high impact study was our early HTA model for a biomarker to assess if patients at intermediate risk for a cardiovascular incident would benefit from statins. While an important improvement, the biomarker test was not cost-effective for two reasons. First, statins have a high budget impact, but not a high price per unit. Second, statins do not have many negative side-effects that could be prevented by a better selection of patients caused by the biomarker.

A particular challenge in estimating cost-effectiveness of medical devices is that the economic evaluation is often performed right before or after market access, while newer devices become available during, or right after the HTA study. This issue requires timely as well as fast assessments, without losing quality. iMTA worked on several high quality economic evaluations, some for NICE, some for industry. In most instances, open surgery was compared to endovascular procedures, for example for TAVI, EVAR, FEVAR and BEVAR procedures. QALY estimates as well as costs were often modelled from intermediate outcomes using Markov models. We also published a key article on modelling issues in cardiovascular diseases and potential solutions.

To populate cost-effectiveness models, iMTA performed systematic reviews of CEAs for Stents, ICDs, TAVI, EVAR and lifestyle interventions. Our main conclusion from these reviews: effectiveness is often well demonstrated but divergent methods for estimating cost-effectiveness cause a wide range of cost per QALY outcomes.

As we often work with biomarker tests, we often make a decision-tree to identify false-positive and true-positive patient responders to the test, followed by a Markov model to assess costs and effects. A great example is our decision analytic model for CT scans versus heart catheterization. Both methods were used to identify heart problems in patients. While heart catheterization is more costly, invasive and involves an increased stroke risk, a CT scan involves radiation exposure. All these elements could be modelled at iMTA to identify the optimal strategy.

All economic valuations require information on patient health status. For cardiovascular conditions, we investigated patients who enter the hospital for Angina Pectoris (chest pain). For these patients, quality of life was assessed. It turned out that the most important factors predicting quality of life scores where the type of angina pectoris (stable/instable), comorbidities such as renal failure and diabetes as well as age. These factors were used to help doctors decide which disease elements should be given most attention during hospital visits.