Some analytical characteristics of a mixed system can be easily described, useful for introducing the effectiveness of risk-sharing methods to improve the performance of a health payment system. The most important observation is that a low-proportional sharing of risks can significantly improve the adjustment between payment and costs. To make this concrete, look at the risk adjustment model used for future Payments to Medicare Advantage Plans in the United States (described in Chapter 19: Medicare Advantage: Regulated Competition in the Shadow of a Public Option), which contains approximately 100 variables and decades of development. The R-square statistic, which describes the adjustment of planned spending to actual expenditures at the personal level, is about 0.11. A proportional risk sharing of only 6% combined with a simple lump sum prospective payment, which corresponds to the average of the population without the risk adjustment taking place at all, can achieve the same adjustment at the individual level. In particular, a mixed system in which a health plan is paid 94% of the average population, then 6% of a participant`s actual cost, provides a cost-based adjustment of payments with a square R equivalent of 0.11.8 This level of adaptation can be calculated and applies to all underlying data. In other words, the R-square equivalent of a proportional risk-sharing plan can be calculated without data analysis (see Box 4.4). There is a long tradition of financial agreements between manufacturers and health systems. However, agreements based on health outcomes have been adopted more recently; the first such agreement was adopted in 2007 in the United Kingdom for the drug Bortezomib. The pharmaceutical company agreed to pay back if the patient did not earn the agreed efficacy rate . In Spain, at the local level, risk-sharing agreements (mainly price volume) have only been used for hospital medicines and have traditionally been managed by hospital pharmacists responsible for the hospital drug budget. New performance agreements have also recently been concluded between hospitals and manufacturers, as well as between regional and national health authorities and pharmaceutical companies.
Spain did not enter into results-based agreements until 2011. The first at the hospital level was in Granada, for Volibris (ambrisentan) . Subsequently, other contracts mainly for cancers were signed between regional health authorities and manufacturers. Barros PP. The simple cost-effectiveness of risk-sharing agreements between the NHS and the pharmaceutical industry. Econ Health. 2011;20:461–70. Our last theoretical comments concern Guvenen (2005).
It starts from a perspective that can be seen as an alternative macro-interpretation of the variable risk-sharing function of this model. Instead of considering workers and shareholders interacting in an uncertain negotiating environment, Guvenen (2005) believes that the population is divided into two groups of unequal access to financial markets.25 Shareholders participate in both equity and bond markets, while non-shareholders act only on bonds. Both groups provide non-elastic labour to the company and non-shareholders are modelled as less risky26 Since borrowing is their only consumer smoothing mechanism, non-shareholders offer bond prices, resulting in a low risk-free interest rate.