[Quality and shortages of patient safety--how big is the problem?].

Patient safety is essential to quality health care, to ensure patients are not harmed, but also to ensure that resources are not wasted. More research evidence is becoming available about deficiencies in health care quality and safety. This evidence is reviewed in three consecutive articles in Läkartidningen. Research has discovered high rates of "adverse events" in health care services. The actual rate varies depending on definition, methods of measurement, and type of service. Rates as high as 46% of patients admitted to hospital have been reported. Sometimes high reported rates indicate that a service is serious about collecting data, rather than being an unsafe service. Generally, half of the events can be classified as "avoidable", and a significant proportion as "serious" causing death, disability or a longer hospital stay. Adverse drug events account for a high proportion and are probably the most well studied of patient safety problems. Although most of the current research has been done in the US, there is some evidence which suggests that problems within Swedish health care are of a similar magnitude and type. This article summarises the main studies and focuses on evidence of the economic consequences of deficiencies in patient safety and quality.