Approximately how much medical harm occurs annually in the US?
Using our definition of medical harm (see question below: “What is ‘medical harm’?”), IHI research, corroborated by academic colleagues, suggests that there are between 40 to 50 incidents of medical harm to patients for every 100 admissions (for the purposes of this calculation, we use a conservative estimate of 40 harm incidents per 100 admissions). With roughly 37 million hospital admissions per year in the United States (AHA National Hospital Survey for 2005), this leads us to conclude that there are (37 million admissions x 40 harm incidents / 100 admissions =) approximately 15 million incidents of medical harm per year in the US.
