Industry estimates suggest total costs of unnecessary medical expenditures resulting from medication non-adherence to be approximately $300 billion, which represents more than 30% of the total waste (excluding fraud and abuse) in the healthcare system. Failure to take prescribed medications costs over $100 billion a year in excess hospitalizations. It is estimated that nearly one-third of patients never fill their prescriptions, and three out of four Americans do not take their medications as directed.

http://healthworkscollective.com/ashish-varshneya/300471/medication-non-adherence-290-billion-unnecessary-expenditure