Most health insurers offer voluntary packages in combination with the basic benefit package. Unlike with basic health insurance, health insurers are free to set premium levels and use risk selection (for example, based on medical criteria or other risks) for complementary VHI. They are also free to define which risks are covered. Most insurers make it unattractive to have VHI without basic insurance by making VHI more expensive if it is not purchased in combination with basic insurance. As a result of risk selection for VHI and the large share of citizens who have VHI, insurers thus have a potentially effective tool to influence access to basic health insurance. A 2010 study revealed, however, that this appeared not to be the case (Roos & Schut, 2010). An interim report of a study by the NZa into the subject concluded that there are indications of risk selection. They found that health insurers tend to attract persons with a favourable risk profile rather than holding off persons with unfavourable risks. It is not yet clear to what extent health insurers deliberately use risk selection (Dutch Healthcare Authority, 2015f).
In the Netherlands VHI can be characterized as complementary as it provides cover for services that are excluded or not fully covered by the Zvw. Health insurers offer a variety of complementary VHI that may cover all kinds of extra care or OOP payments. Re-insurance of the compulsory deductible is allowed via VHI, but in practice this is only offered to social security recipients, people with a minimum income, students and foreign seasonal workers (Ministry of Health, Welfare and Sport, 2014a). In 2015, 84% of the insured purchased complementary VHI. The number of people purchasing complementary VHI decreased gradually over the years: in 2006, 93% of the insured purchased VHI (Vektis, 2015). Most health insurers offer free complementary VHI for children. In practice the child is covered for the same complementary VHI as the parent.
Complementary VHI may include health care that is not evidence-based or that is not considered medically necessary, and/or care that can reasonably be afforded by an individual. VHI covers, for instance, dental care for adults, glasses and physiotherapy (for persons without a chronic indication) since these are considered to be affordable by individuals. An example of non-evidence-based medicine is homoeopathic therapy. Complementary VHI packages vary considerably among insurers, and individual insurers can offer several different packages. The average yearly premium for VHI was €314 in 2013. The average reimbursement per insured was €260 in 2013, the largest share accounted for by reimbursements for dental care (€112 per year in 2013) and allied health care (€71 in 2013). About 78% of the insured have complementary insurance for dental care (Vektis, 2015).