Table 6.

Arguments and counterarguments around co-payments for cost-equivalence

Arguments against cost-equivalence co-payment	Counter-arguments (in favour of cost-equivalence co-payment)
Egalitarian Co-payments are unfair. They mean that wealthier patients are able to access treatments that less-well-off patients cannot afford [5]. Public health care should provide the same treatment to all	Inequality already exists. Patients can access treatments in the private system (if they can afford it). Co-payments reduce inequality by reducing the cost burden of such choices. Levelling down equality benefits no patients [10], but restricts choices for some
Cost-burden It is objectionable that patients might end up accruing very large medical bills in order to access treatment	Patients would not need to pay anything for the most effective available treatment. Some patients already accrue large bills (for private treatment or complementary medicine) Co-payments would reduce the bills for patients who would choose suboptimal treatments
Market effects PHS that apply strict cost-thresholds to medicines are able to negotiate with pharmaceutical companies to reduce their prices (below the ICER threshold). Co-payments would reduce the incentive for companies to drop prices, and potentially deprive other patients of treatment [21]	The number of patients choosing suboptimal treatments is likely to be low (compared to the size of the PHS)—therefore having little impact on market negotiations of the PHS [46]. On the other hand, if there were a large number of patients choosing co-payments for desired (but suboptimal) treatment, this would suggest that (a) many individuals judged the level of copayment acceptable, and (b) the PHS should reconsider its decision not to provide it
Slippery Slope Permitting co-payments (for sub-optimal treatment) would lead to wider use of co-payments within the PHS, and to progressive reduction in the funding and effectiveness of the PHS	Co-payments already exist in many PHS for some elements of healthcare (e.g. in the UK for dentistry/opticians). They have not led to a progressive decline in PHS. Co-payments for optimal treatment can be distinguished from co-payment for sub-optimal treatment. Permitting one, does not necessarily mean permitting the other