Prescription cost sharing: economic and health impacts, and implications for health policy.

Cost sharing for prescription pharmaceuticals--in the form of copayments, coinsurance, or deductibles--is now common in healthcare systems throughout the world. Although there are no studies that directly or convincingly measure the effects of prescription cost sharing on health status or treatment outcomes, cost sharing does appear to reduce utilisation of pharmaceuticals; however, more information is required concerning the relationship between cost sharing and prescription-filling behaviour. Additionally, outcomes studies are needed to define appropriate and inappropriate cost-sharing levels for particular groups of patients, based on income, disease, employment status, and other factors. Cost sharing for pharmaceuticals and other medical services is likely to increase in the near future. As a result, consumers will have a greater role in treatment decisions and will also become more interested in knowing the value of the medicines they are asked to purchase. They are therefore likely to demand pharmaceutical products that are more cost-effective and products that improve quality of life. The increased implementation of cost-sharing programmes necessitates the adoption of appropriate cost-sharing policies, which incorporate the following general principles: 1. Consumers must be provided with the information required to make informed decisions, including the value of the medication, its importance in the treatment plan, and the consequences of not having the prescription filled. 2. Aggressive or abusive cost-sharing features that deny access to optimal pharmaceutical therapy must be avoided. 3. Inappropriate cost sharing, either fixed level or percentage of the prescription cost, may affect disease control and ultimately health or functional status. 4. Cost sharing restricted to pharmaceuticals may encourage replacement of drug therapy with more expensive forms of treatment; therefore, cost sharing should apply to the full range of medical services to prevent service substitution.