Discussion
Using the comprehensive Vektis databases, we were able to estimate the real-world age group-specific incidence of heart valve implantations, subsequent survival and complications as well as the associated healthcare costs of all patients in the Netherlands who had undergone a heart valve implantation during our study period. Although the estimates are specific to the Dutch healthcare system, the results regarding differences between age groups, distribution of costs over types of healthcare and associations between patient and intervention characteristics and healthcare costs are also relevant for other countries. Our results can help raise awareness of the costs associated with heart valve implantations among clinicians and healthcare policy makers, which is important in the current era of limited healthcare budgets. However, we want to emphasise that considerations about costs should not play a role in the treatment decision for individual patients. Instead the results can be used as a benchmark in cost-effectiveness analyses for new technologies that will be introduced in clinical practice in the future, such as tissue-engineered heart valves.5
This study has shown that Dutch health insurers spent over €120 million per year on procedure costs for heart valve implantations, of which 2% is spent on children, 17% on young adults, 26% on middle aged and 56% on elderly patients. Although there were no substantial differences in procedure costs between age groups, the costs of SVR were generally higher in older patients, while costs of TVI were lower for older patients. There was no trend in complication costs in relation to age groups. In addition to procedure costs, patients had excess healthcare costs after the heart valve implantation compared with controls in almost all types of healthcare. These excess healthcare costs were especially high in the year of heart valve implantation; 41 (children), 14 (young adults), 9 (middle aged) and 5 (elderly) fold higher in patients than controls. In the subsequent postintervention years, however, the excess healthcare costs decreased. This decrease may be explained by survival of the fittest patients.
In contrast to other types of healthcare, the costs of nursing homes were substantially lower for elderly patients than for controls. This may be caused by selection bias of relatively healthy elderly patients for SVR. Patients living in nursing homes may be less likely to undergo heart valve implantation due to other factors influencing someone’s health state, such as frailty or dementia. Since these factors could not be taken into account when defining the control sample, people living in nursing homes may be over-represented in the control group as compared with the patient group.
As expected, older age, female gender, comorbidities, low SES and/or experiencing complications (including death) were associated with higher annual healthcare costs. It should be noted that the aim of this study was to describe and predict costs and that it does not make casual claims. Nevertheless, some explanations for the associations can be considered. The association of lower SES and poor health has also been shown consistently in previous research.10 The association of gender and costs, even after adjusting for comorbidities and complications, is in line with previous research that found that women have higher healthcare costs than men.11 In cardiovascular diseases, this might be due to the different preoperative risks profiles of women compared with men,12 13 which may be caused by delayed presentation or diagnosis of valve problems and/or later referral to cardiothoracic surgery of women.12 If these different risk profiles result in slower or impaired recovery of women compared with men, this might result in more use of healthcare and thereby higher annual healthcare costs.
Strengths and limitations
An important strength of our study is the use of databases including the health insurance claims of 99% of Dutch residents. Therefore, almost all patients that have undergone heart valve implantations during our study period were included, and we presented outcomes in a diverse study population that reflects the range and distribution of patients in clinical practice instead of focusing on specific age or risk groups.14 This resulted in comprehensive analyses of the real-world healthcare costs associated with heart valve implantations with high external validity and generalisability. Since healthcare decision makers need information about the cost-effectiveness in the real world, our results provide valuable input for the costs in cost-effectiveness analyses based on data generated in routine care instead of under experimental conditions.14 Furthermore, this study provided a unique insight in the differences in incidence, health outcomes and associated healthcare costs of heart valve implantations of patients with all ages, divided over four informative age groups.
Our study also has some limitations. First, we could not separate our results for different types of valve prostheses (eg, mechanical and biological prostheses). However, although the type of prosthesis has impact on survival and complication rates, we do not expect that the type of prosthesis has a large impact on healthcare costs. Furthermore, since the DRG code for TVI was only available from 2013, the follow-up was too short to estimate annual healthcare costs in postintervention years for these patients. Additionally, since complications were identified using DRG codes, we could only determine the incidence and costs of complications for which patients were treated in the hospital (including outpatient treatment). Furthermore, not all inhospital complications could be identified because for some complications the costs may be included in the DRG of the initial heart valve implantation instead of a separate DRG. In addition, the exact date of the heart valve implantation was unknown; instead, the opening date of the DRG in the financial administrative system was used as a proxy. It is possible that the heart valve implantation took place a few days/weeks before or after the opening date of the DRG. Furthermore, we could not calculate annual healthcare costs from the exact date of the intervention onwards but only from the quarter in which the intervention took place. Finally, the reported costs are expenditures reimbursed by health insurers based on agreements between healthcare providers and insurers, not actual costs.